Basic Hemodynamic Monitoring

Transcription

1 Notebook Basic Hemodynamic Monitoring Lesson 1: Basics of Hemodynamic Monitoring Systems Lesson 2: Arterial Pressure Monitoring Lesson 3: Central Venous Catheters Lesson 4: Pulmonary Artery Catheters Lesson 5: Cardiac Output Monitoring Lesson 6: Oxygenation and Transport Lesson 7: Pharmacological Management of Hemodynamics Inside: Module Outline Lesson Objectives Lesson Summary Lesson Resource Files Lesson Practice Pearls

2 Module Outline 2 Module 4 - Basic Hemodynamic Monitoring Lesson 1 - Basics of Hemodynamic Monitoring Systems Topic 1: Basic Components Of The Hemodynamic Pressure Monitoring Systems Topic 2: Obtaining Accurate Hemodynamic Values Lesson 2 - Arterial Pressure Monitoring Topic 1: Catheter Types And Insertion Techniques Topic 2: Complications Or Arterial Monitoring Topic 3: Waveforms And Clinical Applications Topic 4: Direct Vs. Indirect Measurement Of Arterial Pressure Topic 5: Obtaining Blood Samples Topic 6: Arterial Catheter Removal Lesson 3 - Central Venous Catheters Topic 1: Catheter Types Topic 2: Insertion Of Central Catheters Sites And Techniques Topic 3: Managing Central Venous Catheters Topic 4: Waveform Analysis And Clinical Applications Topic 5: Complications Topic 6: Water Vs. Pressure Transducer Monitoring Lesson 4 - Pulmonary Artery Catheters Topic 1: Indications For PA Catheter Topic 2: Catheter Types Topic 3: Insertion Topic 4: Managing And Troubleshooting PA Catheters Topic 5: Waveform Analysis Topic 6: Complications And Associated Problems Topic 7: Clinical Applications Lesson 5 - Cardiac Output Monitoring Lesson 1: Factors Affecting Cardiac Output Lesson 2: Methods Of Calculating CO Lesson 3: Clinical Application Of CO Lesson 4: Non-Invasive CO Monitoring Lesson 6 - Oxygenation And Transport Topic 1: Oxygen Supply And Demand Topic 2: Types Of Catheters (SVO2, Scvo2) Topic 3: Conditions Affecting Oxygen Monitoring Topic 4: Clinical Applications Lesson 7 - Pharmacological Management Of Hemodynamics Topic 1: Managing Preload Topic 2: Managing Afterload Topic 3: Managing Contractility

3 Lesson 1 Basic Components of Hemodynamic Systems Included in this Lesson: Basic Components Of The Hemodynamic Pressure Monitoring Systems Obtaining Accurate Hemodynamic Values

4 4 Lesson Objectives Module: Hemodynamic Monitoring Lesson: Basics of Hemodynamic Monitoring Systems Upon completion of this lesson you will be able to: Identify and describe the components of a hemodynamic monitoring system - Describe the basic elements of hemodynamic pressure monitoring equipment. - Identify mechanisms used to ensure accurate pressure measurements.

5 Page of 5 5 Lesson Takeaway - Basics of Hemodynamic Monitoring Systems Topic One: Basic Components of Hemodynamic Pressure Monitoring Systems Introduction In this lesson we look at the hemodynamic monitoring system itself which offers the clinician a relatively simple way of measuring the dynamic conditions of the cardiovascular system at the bedside. We learn how to set up a hemodynamic pressure monitoring system and explore the fact that with advances in electronics and computer systems, there have also been advances in the monitoring of cardiovascular hemodynamics. Blood Pressure Monitoring blood pressure is the most basic way to monitor a patient s hemodynamic status. Can be done noninvasively using a sphygmomanometer and stethoscope or invasively using an arterial catheter and electronic monitor If system is set up correctly, these BP values are highly reliable and valid: When measured noninvasively via a cuff, BP values depend on the detection of pulsations within the artery to determine the systolic and diastolic values. When measured directly via a catheter placed inside the artery, BP values are taken directly from pressures detected inside the vessel itself. Pressure Monitoring Systems 2 basic types: Fluid filled monitoring systems (most common) Have become obsolete in the critical care unit because are easily contaminated (because of their open nature) and only allow for intermittent readings Fiberoptic monitoring systems (newer) Closed Fluid Filled Monitoring System The most commonly used form of hemodynamic monitoring system Is coupled with a transducer and connected to an amplifier/monitor for continuous readout of pressures in mmhg Catheter for Pressure Monitoring Catheter is the device used to access the body cavity or vessel where pressures will be measured Different types are used based on hemodynamic parameter being measured. For measuring arterial pressure For measuring CVP While fluid filled pressure monitoring systems are usually used for measuring hemodynamic pressures, they can also measure pressures from other parts of the body American Association of Critical-Care Nurses (AACN). All rights reserved.

6 Page of 5 6 Note: Different standards exist for using the fluid filled pressure monitoring system to measure nonhemodynamic pressures. Hemodynamic Monitoring Kit Commercially available hemodynamic monitoring kits used by most facilities. Are an improvement from the non-disposable systems of the past Contain items needed for set-up: Low compliance tubing Transducer Flush device Stopcocks Flushing to Maintain Patency of the Catheter Purpose of flush system and solution: Maintain patency of the catheter to which the hemodynamic monitoring system is connected How accomplished: The flush solution bag is surrounded by an inflatable pressure bag maintained at 300 mmhg. Size of bag must match the size capacity of the inflatable pressure bag. All transducer flush systems are calibrated to deliver continuous flow at 3-5 ml/hr when pressure bag is properly maintained (at 300 mmhg.) This constant pressure: Maintains continuous rate of flow through catheter, preventing occlusion Provides means of intermittent, rapid manual flushing of the catheter Provides way to test the waveform s dynamic response (called square wave testing. ) Transducer Cable, Amplifier and Monitor The amplifier/monitor and cable transfer electrical signal from transducer to the over bed monitor display. The monitor can only interpret (and display) the signals it gets If proper setup/maintenance is absent, monitor s readings may be wrong. Strip Recorder Allows user to document the waveform on paper for further analysis Especially important when waveform has significant movement from baseline Most can record in single channel (one waveform per strip) or dual channel (2 waveforms per strip) - When analyzing hemodynamic waves, select dual channel when available American Association of Critical-Care Nurses (AACN). All rights reserved.

7 Page of 5 7 Topic Two: Obtaining Accurate Hemodynamic Values Introduction Here we explore how to ensure that the hemodynamic values you get are accurate and that your monitoring system is accurate. Obtaining Accurate Hemodynamic Values Fluid in motion exerts hydrodynamic pressure. Pressures within the cardiovascular system do as well, except that due to inertia, there is a lag between the actual force/pressure occurring and the recording of that force on the EKG. Therefore: Keep the tubing as short as possible. The shorter the tubing, the less the lag. Hydrodynamic Pressure and Principles of Fluid in Motion Hemodynamic pressure waves: Complex waves of differing amplitude and frequency which, when combined, produce the waveform ultimately viewed on the monitor. Essential to understand the factors affecting frequency response and to know how to correct it because when a hemodynamic monitoring system is not functioning optimally, the waveform s shape and amplitude will be distorted and end result could be inaccurate treatment of patient. Factor Affecting Frequency Response Factors that can have an effect on this frequency response: Excess tubing length Keep as short as possible. Never exceed 3-4 feet in length. An improperly-flushed transducer and monitoring system The transducer and monitoring system are fluid-filled and it is the fluid column within the tubing that transmits the signal from patient to transducer. If improperly-flushed, there will be excess dampening and inaccurate results. Preventing/avoiding bubbles and compliant loose/flabby tubing since both can result in excess harmonics and an overshoot or undershoot of hemodynamic values Do the priming of the tubing (to reduce bubbles) prior to inflating the pressure bag and examine stopcock intersections to ensure that all air has been removed from the stopcock. Keep in mind that patients with hyperdynamic circulation produce waveforms that are an overshoot of actual values. Keep in mind that patients with tachycardia also produce waveforms that overshoot values since tachycardia increases the number of signals per minute being transmitted to the monitor. Be sure monitoring system s dynamic response is accurate American Association of Critical-Care Nurses (AACN). All rights reserved.

8 Page of 5 Dynamic Response Testing Dynamic response test ( square wave test ) helps you evaluate whether your monitoring system s dynamic response is accurate. Should be done: Whenever assessing a patient Anytime you suspect your values are not accurate Easy to do. Done by activating the fast flush device on the transducer for 1-2 seconds. Evaluate the bounce back. Actions of an optimally-damped system Actions of an over-damped system Actions of an under-damped system Leveling the Transducer Required in order for hemodynamic measures to be accurate Transducer is leveled with patient s right atria to a point at the patient s fourth intercostal space, at the midaxillary point. (This point is called the phlebostatic axis.) Transducer Placement Using a leveling device, place transducer at a level horizontal with the phlebostatic axis. Any type of level fine, electric, laser or even simple carpenter s level Never eyeball or estimate. Can result in large variation in your numbers. Transducer placed by positioning the air-reference stopcock at the same horizontal level as the phlebostatic axis. Some institutions place transducers directly on bed or on patient s chest at phlebostatic axis. Many institutions mount transducer in a manifold on an IV pole at the bedside (instead of directly on bed or patient s chest.) In IV pole approach, important to relevel transducer whenever the head of the bed position is changed. Effects of Position Changes on Hemodynamic Monitoring Being only one inch off from the correct level can change pressure readings by 2 mmhg! This can be difference between treating and not treating a patient. A too-high transducer level produces too-low values. A too-low transducer level produces too-high values. Re-level the transducer every time you change a patient s position American Association of Critical-Care Nurses (AACN). All rights reserved.

9 Page of 5 9 Zero Referencing After leveling transducer, we zero the transducer. This is done to ensure that pressures being measured are result of patient s hemodynamic system and not of atmosphere or fluid. Zeroing basically tells transducer to ignore the effects of: Weight of the atmosphere Weight of the fluid in the system 5 basic steps for zeroing a transducer: Level transducer. Turn stopcock nearest transducer off to patient and open to the capped stopcock port. Remove cap to stopcock port, opening it to air. Activate zero function key on monitoring device. When monitor indicates that system is properly zeroed, replace cap to stopcock port. Then turn stopcock back so that it s off to the cap and open to the patient American Association of Critical-Care Nurses (AACN). All rights reserved.

10 10 Troubleshooting Fluid-Filled Lesson: Basics of Hemodynamic Monitoring Systems Monitory Systems Topic: Obtaining Accurate Hemodynamic Values Hemodynamic Monitoring Troubleshooting Guide Problem Cause Prevention Intervention No waveform on monitor Stop cocks not open to patient monitoring position. Check stop cocks for proper position. Correct stop cock position. Inappropriate zero. Zero the transducer periodically per hospital policy. Re-zero the transducer. Scale for pressure being measured incorrect. Set pressure monitoring scale to appropriate level for pressure being measured. Check monitor to assure appropriate level has been set. Clotted catheter. Keep flush bag inflated to 300mmHg Check flush bag to assure it is inflated properly. Aspirate catheter if possible. Follow hospital policy regarding clearing of clotted catheters. DO NOT ATTEMPT TO FLUSH FORWARD. Faulty transducer. Change transducer. No cable, cable not connected, monitor malfunction. Check cable connections. Change cable, refer to biomedical engineering. Dampened waveform (over damped) Air bubbles in tubing / stopcocks. Flush system with gravity only. Check tubing and stop cocks carefully for air bubbles prior to connecting. Flush bubbles from system. Improper scale selection Utilize appropriate scale for the pressure being measured. Place scale at appropriate level.

11 11 Problem Cause Prevention Intervention Partial occlusion of catheter &/or catheter tip. Maintain pressure bag at 300mmHg, maintain adequate flush solution, follow hospital policy regarding the use of anticoagulants in the flush solution. ASPIRATE catheter (NEVER FORWARD FLUSH before aspirating, could dislodge clot material into circulation). Reinflate pressure bag or replace flush solution. Have patient cough. Reposition catheter (follow hospital policy.) Leak in tubing / set. Tighten all connections. Check to assure all connections are tight. Readout values too high or too low. Transducer level too high (readouts too low). ALWAYS check level with leveling device. Confirm level at phlebostatic axis. Transducer level too low (readouts too high). ALWAYS check level with leveling device. Confirm level at phlebostatic axis. Improper zero. Periodically re zero the transducer. Check zero, rezero as necessary. Ringing / fling or whip in catheter. (under damped) Excess tubing length or use of compliant tubing. Use non compliant tubing. Make sure tubing is less than 4 feet from the catheter connection to the transducer. Change tubing, shorten length. Excess catheter movement. Catheter may require repositioning, follow hospital policy &/or consult MD. Excessive stop cocks in system Keep inline stop cocks to a minimum. Remove excess stop cocks. Change in waveform configuration. Catheter migration to a different location. Reposition the patient. Obtain a Chest x-ray. Follow hospital procedure to reposition the catheter if necessary. Loose connections in system. Tighten connections.

12 12 Problem Cause Prevention Intervention Electrical interference. Tighten all connections between the transducer and the monitoring system. Move electrical equipment with moving parts away from the transducer. Bleed back into tubing Loose connections in system. NOTE: If blood gets into the transducer, the transducer will need to be changed. Check & tighten all connections. Stop cock turned off to transducer (instead of to patient) when opening to air. Turn stop cocks off to patient when zeroing transducer. Pressure bag deflated Check pressure bag frequently to assure 300mmHg is maintained. High Risk for infection from invasive lines. Breaks in sterile technique ALWAYS maintain sterile technique. Keep stop cock ports sterile and always maintain sterility of stopcock ports. If infection is suspected, contact MD to review antibiotic coverage, When discontinuing catheter, culture catheter tip. Prolonged therapy Discontinue invasive catheters when no longer needed. Contaminated flush solution Change flush bags and solutions per hospital policy. Monitor for signs and symptoms of infection

13 13 The Essentials of Lesson: Basics of Hemodynamic Monitoring Systems Hemodynamic Monitoring Topic: Basic Components of Hemodynamic Pressure Monitoring Systems Practice Pearls Pressure Monitoring Systems We will discuss the water manometer system briefly in the section on central venous pressure monitoring. This system is used on occasion in areas where electronic hemodynamic monitors are not available. Catheter for Pressure Monitoring You are measuring the pressures where the line TERMINATES! For example, a central line may originate at the right internal jugular vein, but the catheter terminates at the superior vena cava. Thus, any hemodynamic pressures obtained from that catheter would be measuring the pressure in the superior vena cava or central veins (CVP). Flushing to Maintain Patency of the Catheter Once the tubing and all stopcock ports are flushed and fluid filled without air bubbles, replace all the vented stopcock caps with the nonvented stopcock caps. This will prevent any possibility of air entering the system.

14 14 The Essentials of Lesson: Basics of Hemodynamic Monitoring Systems Hemodynamic Monitoring Topic: Obtaining Accurate Hemodynamic Values Dynamic Response Testing Remember, when flushing a catheter, if you in anyway suspect clotting of the catheter you must ALWAYS ASPIRATE the catheter prior to using the fast forward flush device. Transducer Placement Remember, the phlebostatic axis is on the patient s chest. Every time you raise or lower the head of the patient s bed, the transducer will need to be releveled. Zero Referencing When removing the cap from the stopcock, care must be taken not to contaminate the cap. You can do so by placing it on a piece of sterile gauze while zeroing, or you can replace the cap with a new sterile one.

15 Lesson 2 Arterial Pressure Monitoring Included in this Lesson: Catheter Types And Insertion Techniques Complications Or Arterial Monitoring Waveforms And Clinical Applications Direct Vs. Indirect Measurement Of Arterial Pressure Obtaining Blood Samples Arterial Catheter Removal

16 16 Lesson Objectives Module: Hemodynamic Monitoring Lesson: Arterial Pressure Monitoring Upon completion of this lesson you will be able to: Describe the elements of and nursing considerations for arterial pressure monitoring - Discuss indications and contraindications for Arterial Catheters - Identify arterial pressure catheter types and nursing considerations for insertion. - Identify arterial pressure catheter types and nursing considerations for insertion - Discuss nursing care of patients with an arterial pressure catheter - Describe complications and troubleshooting measures of arterial pressure catheters. - Identify the components of the arterial pressure waveform - Discuss difference between direct and indirect arterial pressure monitoring and nursing implications.

17 Page of 7 17 Lesson Take-away Arterial Pressure Monitoring Topic One: Catheter Types and Insertion Techniques Introduction In this lesson we explore arterial pressure monitoring, one of the most common forms of invasive pressure monitoring and a common invasive procedure among the critically ill. We learn about commonly used arterial catheter insertion sites and look at different arterial catheter types and the insertion techniques. We also explore the complications you may encounter with an arterial line. We analyze and discuss some different arterial waveforms and review arterial line blood sampling removal. We also briefly discuss the difference between direct and indirect blood pressure monitoring. Direct Arterial Pressure Measurement The type of blood pressure monitoring used when a procedure or the patient s condition requires that blood pressure be monitored with the greatest of accuracy. Following cardiac surgery or other high-risk surgeries When patient is hypotensive (systolic blood pressure less than 90 mmhg) and requires medications such as vasopressors to support and maintain the blood pressure When ready access to blood samples (for lab tests or for arterial blood gases) is needed Arterial Catheter Catheter inserted into an artery Arterial sites used Informed Consent must be obtained Informed consent must first be obtained. Physician/nurse needs to be experienced inserting catheter and familiar with catheter and associated equipment 90% of all arterial catheters inserted in either radial or femoral artery Radial Artery Placement Circulation of hand by radial and ulnar arteries Some have poor flow through ulnar artery If radial artery becomes cannulated, dramatic loss of blood flow, tissue ischemia, an loss of hand possible. If inserting catheter into the radial artery, use Allen s Test American Association of Critical-Care Nurses (AACN). All rights reserved.

18 Page of 7 18 Allen s Test Assesses the adequacy of blood flow and perfusion through ulnar artery Performed by compressing both the radial and ulnar arteries at wrist Use nondominant hand 2 Steps Pressure Monitoring System Setup Needs to be done prior to catheter insertion Includes setting up transducer system, flush solution and pressure bag should be set up at the bedside. Process of set-up Arterial Catheter Insertion Usually an arterial catheter kit is used but sometimes individual components are gathered at bedside. Steps of insertion same for both: Sterile gloves and catheter kit Locate artery and insert Connect to pressure monitoring system Suture catheter in place Sealing and applying sterile dressing Referencing Catheter to the Phlebostatic Axis Next step is to reference the catheter to the phlebostatic axis and zero the system according to the procedure for the bedside monitor. Verify integrity of waveform and print hard copy. Record the systolic, diastolic, and mean arterial pressures. Advantages vs. Disadvantages of Using the Radial Artery Advantages Easy to locate Accessible during most types of Cannulated surgery Immobilization of the site fairly easy and comfortable for patient 2008 American Association of Critical-Care Nurses (AACN). All rights reserved.

19 Page of 7 19 Disadvantages Complications can result from prolonged use Thrombus formation possible Cannulation of artery requires smaller catheter which can cause waveforms that over-shoot giving inaccurate/overly large results Potential injury to adjacent nerves with hematoma formation Femoral Artery Catheter Done when radial artery may not be accessible or if a large bore catheter needs to be used. Done most often in cardiac catheterization lab or in surgery. If done in ICU, the steps followed include: Site preparation by physician Catheter insertion into femoral artery Nurse immediately connects catheter to pressure monitoring system and flushes catheter. After catheter sutured into place and sterile dressings applied, nurse writes write date, time, and initials on dressing. Advantages vs. Disadvantages of Using the Femoral Artery Advantages: Pressure line remains patent longer with fewer complications. Less distortion of waveform Because larger than radial artery, can accommodate a larger catheter Disadvantages: Requires patient remain supine Difficult to immobilize if patient agitated or restless Cannot be used if intra-aortic balloon pump is to be used Brachial Artery an Alternative to the Radial Artery Larger than radial artery and easier to locate and cannulate May be artery of choice if radial artery cannot be cannulated Disadvantages: Creates difficulty immobilizing arm and discomfort for patient since it s located at elbow The possibility for thrombus material from the catheter to dislodge and impair blood flow to the lower arm/hand American Association of Critical-Care Nurses (AACN). All rights reserved.

20 Page of 7 20 Axillary Artery Catheter Arterial catheter inserted into the axillary artery only when/if: Other arterial access may cannot be used Severe peripheral vascular disease present Produces waveform similar to aortic waveform; pressure closely correlates with central aortic pressure. Must be careful to avoid introducing air or thrombus material into the system when flushing catheter or obtaining blood samples. Main disadvantage: Cannulation technically difficult; requires arm to be rotated, abducted, and extended upward to level of shoulder. Topic Two: Complications of Arterial Pressure Monitoring Introduction Here we look at the infrequent, but possible complications that can occur with arterial pressure monitoring. Arterial Pressure Monitoring Common complications of arterial pressure monitoring: Peripheral embolization Air embolus Bleeding around catheter insertion site In cases where femoral artery used, bleeding in surrounding tissues Retroperitoneal bleeding Thrombosis of effected artery Vascular insufficiency Patient Safety Patient safety issues related to arterial pressure monitoring: The chance for accidental administration of medication through arterial line Blood loss due to stopcock turned wrong way Topic Three: Waveforms and Clinical Applications Here we examine waveforms in detail. Systemic Arterial Waveform A rapid upstroke and rounded peak followed by a rapid downstroke Notch observed on the rapid downstroke is called the dicrotic notch American Association of Critical-Care Nurses (AACN). All rights reserved.

21 Page of 7 21 After dicrotic arch, the fall in waveform pressure is smooth and progressive (called the reflection wave) during diastole until the next systolic upstroke. Measuring the Systemic Arterial Waveform To measure the systemic arterial waveform, locate and measure the peak systolic and end-diastolic values using the measurement scale to the left of the waveform. Using the ECG as a Reference Arterial peak systole and end-diastole can be identified using the ECG. End-diastole occurs simultaneously with the end of the QRS complex. Peak systole occurs after the QRS. Then, as before, measure the systolic and diastolic pressure using the scale. Waveform Morphology Considerations The arterial pressure waveform shape and value changes depending on measurement site. The farther away the site from the aorta: The more peaked the systolic portion of waveform and the higher amplitude The less distinct the dicrotic notch (often absent in femoral artery waveforms) The greater the delay following the QRS complex Normal Variations in Pressure Waveform Contour and Value Radial artery pressure values are higher than aortic pressure values, and femoral artery values are higher than both radial and aortic. Therefore, getting a low pressure reading is more worrisome in some cases than in others. Example: A femoral artery pressure of 100/50 mmhg would be more worrisome than a radial artery pressure of the same amount American Association of Critical-Care Nurses (AACN). All rights reserved.

22 Page of 7 22 Pressure at the Tip of the Catheter Important to remember that the pressures recorded here (at tip of catheter) do not change based on site of monitoring. They (the mean arterial pressure) are actual and will remain same, regardless of site of monitoring. Atrial Fibrillation Often associated with variation in amplitude of the arterial systolic waveform The longer the R to R interval, the more time the ventricle has to fill, and therefore the larger stroke volume it ejects. Therefore, peak systolic pressure is higher in the beat terminating the longer R to R interval. Topic Four: Direct vs. Indirect Measurement of Arterial Pressure Introduction Here we explore the fact that noninvasive (cuff) blood pressure and direct arterial pressure are not the same. Indirect vs. Direct Arterial Pressure Measurement The two are often assumed to be the same, but they don t always match up. Reasons they are not the same Reasons why they don t always match up. The amount they differ: In normal patients, direct arterial pressure usually 2-8 mmhg higher than cuff pressure. In critically ill patients, direct arterial pressure is often mmhg higher than the cuff pressure, and differences of mmhg between the two have been reported. Variations in Configuration of Arterial Waveform Variation in the arterial waveform often due to changes in physiologic processes rather than to system error. However, if you question accuracy, be sure that: Blood can blood be drawn from the catheter The system can be zeroed There is a mechanism to keep the catheter clear between the pressure source and the transducer The waveform is dependable 2008 American Association of Critical-Care Nurses (AACN). All rights reserved.

23 Page of 7 23 Topic Five: Obtaining Blood Samples Introduction Here we look at both open and closed systems for drawing blood for lab tests. Ready Access to Draw Blood Provided by arterial catheter Two types of systems for blood sampling from an arterial line: Open Closed Procedure for using Open system Closed System Highly recommended because: Reduces likelihood of contamination or introduction of bacteria into system Contributes to blood conservation since no need to discard aspirated solution/blood Procedures for using closed system Topic Six: Arterial Catheter Removal Here we look at the timing and steps of removing the arterial catheter. Arterial Catheter Removal Done when it is no longer required for continuous arterial pressure monitoring or frequent blood gas samples Steps: Remove dressing Aspiration of blood Apply pressure Pressure dressing 2008 American Association of Critical-Care Nurses (AACN). All rights reserved.

24 24 Catheter Placement Lesson: Arterial Pressure Monitoring Topic: Catheter Types and Insertion Techniques Catheter Placement Advantages Disadvantages Radial Artery The artery is easy to locate and cannulated. The artery is accessible during most types of surgery. Immobilization of the site is fairly easy and comfortable for the patient. Femoral Artery Pressure line tends to remain patent longer with fewer complications. Waveform tends to be more reflective of the actual aortic waveform, i.e., less distortion. Femoral artery is larger accommodating a larger catheter. Prolonged use may lead to complications such as vascular occlusion. Thrombus formation may occur occluding the catheter. Cannulation of the artery requires a smaller catheter which can contribute to overshoot of the waveform giving an over estimation of the systolic pressure. Potential injury to the adjacent nerves with hematoma formation. Increased risk of bleeding (larger artery) and retroperitoneal bleeding. Requires the patient to remain supine to prevent bending the catheter. Difficult to immobilize if patient is agitated or restless. Cannot use if an intra-aortic balloon pump is to be used.

25 25 Brachial Artery The brachial arteries is larger than the radial artery and may be the artery of choice if the radial artery cannot be cannulated. Larger vessel and easier for the clinician to locate and cannulate. Axillary Artery Occurs infrequently in situations where other arterial access may not be accessible or severe peripheral vascular disease is present (example: Raynaud s Disease). The artery is large and closer to the aorta providing a waveform similar to the aortic waveform. The pressure closely correlates with the central aortic pressure. Location at the elbow creates difficulty with immobilization of the arm and discomfort for the patient. Thrombus material from the catheter could dislodge and impair blood flow to the lower arm and hand. Care must be taken when flushing the catheter or obtaining blood samples to avoid introducing air or thrombus material into the system. This could potentially travel to the cerebral circulation. Cannulation is technically difficult requiring the arm be rotated, abducted and extended upward to the level of the shoulder.

26 26 Arterial Pressure Measurement Lesson: Arterial Pressure Monitoring Topic: Direct vs. Indirect Measurement Many clinicians will compare the noninvasive (cuff) blood pressure with the direct arterial pressure assuming both are equal. A common practice is to state the arterial line pressure correlates with the cuff pressure. Of interest is which set of numbers to accept if they do not correlate.

27 27 The Essentials of Lesson: Arterial Pressure Monitoring Hemodynamic Monitoring Topic: Complications of Arterial Pressure Monitoring Practice Pearls Arterial Pressure Monitoring Factors Increasing the Risk for Complications Associated with Arterial Pressure Monitoring 1. Large bore catheters (greater than 20 gauge unless placed in a femoral artery) 2. Inserted via Cutdown 3. Multiple puncture attempts 4. Frequent non-invasive blood pressure measurements on the same arm as the arterial line 5. Flush system not working properly 6. Hypercoagulable states 7. Low cardiac output associated with markedly impaired peripheral blood flow 8. Failure to label the line as arterial

28 28 The Essentials of Lesson: Arterial Pressure Monitoring Hemodynamic Monitoring Topic: Direct vs. Indirect Measurement of Arterial Pressure Indirect vs. Direct Arterial Pressure Measurement The mean arterial pressure (MAP) will remain the same regardless of which technique is used. Variations in Configuration of Arterial Waveform Important thoughts: 1. If the system is questioned, we should fix it! 2. We are monitoring trends and not treating an absolute number!

29 29 The Essentials of Lesson: Arterial Pressure Monitoring Hemodynamic Monitoring Topic: Obtaining Blood Samples Ready Access to Draw Blood If an arterial blood gas blood sample is to be obtained, use a heparinized syringe. Pull back on the plunger of the syringe very slowly being sure that there are no air bubbles in the syringe. Air bubbles will distort the blood gas measurement. Fill the syringe with approximately 4 to 5 ml of blood. Turn the stopcock off to the patient and disconnect the syringe. Immediately cap off the syringe taking care to be sure no air has entered into the blood sample. Immediately place the syringe on ice. Placing the syringe on ice will extend the amount of time (up to 30 minutes) for the blood gas analysis to be obtained otherwise the gas analysis should be run within 10 minutes. Most recommend icing the sample.

30 Lesson 3 Central Venous Catheters Included in this Lesson: Catheter Types Insertion Of Central Catheters Sites And Techniques Managing Central Venous Catheters Waveform Analysis And Clinical Applications Complications Water Vs. Pressure Transducer Monitoring

31 31 Lesson Objectives Module: Hemodynamic Monitoring Lesson: Central Venous Catheters Upon completion of this lesson you will be able to: Discuss the indications for, contraindications of, and general management principles for central venous catheters. Identify the characteristics of normal and abnormal central venous pressure waveforms. - Identify Central Venous Catheter types - Identify Central venous catheter insertion sites and procedure - Describe management and nursing implications of central venous catheters - Identify complications of central venous catheters - Identify the components of the central venous pressure waveform - Discuss the possible causes and management of increased and decreased central venous pressures - Interpret and discuss the difference between central venous pressures obtained via water manometer and pressure transducer

32 Page of 8 32 Lesson Takeaway Central Venous Pressure Monitoring Topic One: Catheter Types Introduction In this lesson we learn about various different central venous catheter types, insertion techniques, and sites. We also explore how to manage CVP lines, analyze CVP waveforms, and handle some of the more common complications encountered with CVPs. We also briefly discuss the use of water manometers to obtain a CVP reading and compare that with values obtained using the pressure transducer. Central Venous Pressure Monitoring First Used Central Venous Pressure (CVP) an important indicator of cardiac preload (venous return) and the intravascular volume CVP monitoring: Hemodynamic monitoring using central venous catheters Not routinely accepted until 1960s Considered first step in bedside invasive cardiac monitoring Because CVP was discovered to be unreliable for use in measuring left heart function, pulmonary artery catheter was introduced Inflation of small balloon on tip of catheter allowed for indirect assessment of left heart pressures and function. Ultimately came to measure not just pulmonary artery pressure but CVP too Central Venous Term central venous generally considered to be within the thoracic cavity CV pressure often used interchangeably with right atrial pressure (RAP) since the difference between the two is generally insignificant clinically Indications: Fluid resuscitation Hemodynamic monitoring Medication administration Inability to access peripheral veins Dialysis Plasmapheresis Transvenous pacemaker placement Contraindications: Infection Trauma Venous thrombosis at the selected site 2008 American Association of Critical-Care Nurses (AACN). All rights reserved.

33 Page of 8 33 Types of Central Venous Catheters A large-gauge single lumen catheter For rapid administration (often 1 liter per minute) of large volumes of fluid A multilumen catheter Can have 2, 3, or 4 ports; most commonly 3 (called a triple lumen catheter) Allows for simultaneous medication/fluid infusions as well as one port to be used for continuous CVP monitoring Each lumen must be flushed and capped prior to insertion. Use distal port to guide catheter into blood vessel. Topic Two: Insertion of Central Catheters Sites and Techniques Introduction Here we discuss insertion points for a central venous catheter. Catheter Insertion Points 3 possibilities: Subclavian vein Internal jugular vein Femoral vein. Consider patient s individual circumstances to decide. Accessing a Vein Done by performing one or the other of these: Cutdown An incision directly over the target vein Used only if/when the vein is undetectable Percutaneous insertion Into the vessel, introducing a needle attached to a syringe Blood is aspirated into the syringe. Can use either of two access systems or insertion techniques: - Seldinger technique Catheter-Over-Needle technique 2008 American Association of Critical-Care Nurses (AACN). All rights reserved.

34 Page of 8 34 Venous Catheter Insertion Techniques Percutaneous insertion uses either of two access systems or insertion techniques: Seldinger technique (most common) or Catheter-Over-Needle Details of Seldinger technique Evidence Based Interventions When inserting a central venous catheter, use these evidence-based interventions for decreasing the possibility of catheter-related blood stream infection: Pay diligent attention to hand hygiene. Use chlorhexadine skin antiseptic prep solution on insertion site. Use a large drape over patient in sterile fashion. Practitioner inserting catheter wears hat, mask, sterile gown, and gloves. Assisting practitioner wears the same. All staff in the room wear mask during insertion. Select the most optimal insertion site. Preferred insertion site for nontunneled catheters is subclavian vein. Review line necessity daily and promptly remove unnecessary lines. Most Common Insertion Sites for Central Venous Catheters In the critically ill patient, most commonly used insertion sites for central venous catheters are: Subclavian vein Advantages Disadvantages Internal jugular vein Advantages Disadvantages Femoral vein Advantages Disadvantages 2008 American Association of Critical-Care Nurses (AACN). All rights reserved.

35 Page of 8 35 Topic Three: Managing Central Venous Catheters Introduction Here we look at the management of the central venous catheter once it has been inserted. After Insertion Catheter Procedures Management means taking steps to: Maintain catheter patency Aspirate Flush Secure catheter in place Verify catheter placement Prevent infection by daily assessing the need to continue using the catheter (since one way to prevent infection is to remove it as soon as possible.) Catheter Removal Proper technique crucial since during this procedure, patient at a very high risk for developing air embolus. Patient should remain in bed for at least 30 minutes following the removal of a central venous catheter from the internal jugular vein or the subclavian vein. Removal of a femoral vein catheter involves a different procedure and requires placing the patient at bed rest for a longer period time. Steps of removal Topic Four: Waveform Analysis and Clinical Applications Introduction Here we look at how to analyze the waveform and obtain values. CVP/RAP Waveform Components of a CVP/RAP waveform: Waveform A Wave C Wave V Wave X Descent Y Descent 2008 American Association of Critical-Care Nurses (AACN). All rights reserved.

36 Page of 8 36 Correlation of CVP/RAP Waveform with ECG Correct identification of the waves in the CVP/RAP waveform requires correlation with the patient's ECG. A wave (representing atrial systole) occurs approximately 0.08 seconds after the P wave of the ECG. C wave, if present, occurs at the end of the QRS complex and at the point where the QRS complex joins the STsegment. V wave occurs approximately 0.08 seconds after the T wave of the ECG. Practice CVP/RAP to ECG To do this comparison/correlation of the CVP/RAP waveform and the ECG complex, you will need to: Print a dual channel strip (a hard copy of the ECG and CVP/RAP waveform on the same strip of paper) Follow these steps to mark the respective areas: On ECG, find P wave and draw straight line down towards the waveform. The A wave will follow the P wave in about 0.08 seconds. On ECG, find the end of the QRS complex and, again, draw straight line down towards the waveform. That point on the waveform will mark the onset of the C wave. On the ECG, find T wave and draw straight line down towards waveform. The V wave will follow the T wave. Elevated and Decreased CVP/RAP Normal right atrial pressure: 2-6 mmhg Causes of elevated CVP/RAP: Right ventricular failure Tricuspid valve disease: Stenosis or insufficiency Right ventricular failure Increased preload/hypervolemia Pulmonary hypertension Cardiac tamponade Positive-pressure ventilatory support Adding positive end-expiratory pressure (PEEP) of 5 cm or more to the ventilator Causes of decreased CVP/RAP: Decreased preload/hypovolemia Mean Pressure of the A Wave The very final filling of the ventricle from the atrium occurs during atrial contraction (the A wave of the CVP/RAP waveform). Therefore, to measure the final ventricular filling pressure indirectly using the CVP/RAP waveform, it is best to use the mean pressure of the A wave American Association of Critical-Care Nurses (AACN). All rights reserved.

37 Page of 8 37 Measuring the Mean CVP/RAP Value Steps for measuring the mean CVP/RAP value: Locate the A wave within PR interval. Measure the top and bottom of the A wave, and average these two values. (Or draw horizontal line midway through the A wave and measure this value as done on the latter part of the waveform.) Topic Five: Complications Introduction Here we explore some of the complications associated with insertion of central venous catheters and with central venous pressure monitoring. Complication with Central Venous Catheters & Pressure Monitoring Bleeding Vascular erosions Arrhythmias Infections Fluid overload Thromboembolic complications Air embolism Perforation of right atrium or right ventricle Pneumothorax Bleeding Is usually occult (not visible) Instead blood is in either the tissue or a body cavity. The reason that a chest x-ray following insertion is so important. Vascular Erosion Rare but can occur any time after insertion of the catheter Patients at increased risk if hypertonic solutions being infused or if endothelial lining is friable. More common with Internal Jugular (IJ) or subclavian insertions 2008 American Association of Critical-Care Nurses (AACN). All rights reserved.

38 Page of 8 38 Arrhythmias Occur when catheter tip is introduced into the right atrium or right ventricle. A central venous catheter inserted into subclavian vein or IJ may spontaneously advance into the right ventricle. The arrhythmia occurs from the tip of the catheter touching the endocardial wall. Nosocomial Infection All central venous catheters increase patient s risk of developing a nosocomial infection and severe sepsis. Possible reasons for infection: Poor technique during catheter insertion Introduction/migration of the skin flora into the insertion site Contaminated tubing and pressure transducer/flush system. Use strict sterile technique when changing dressings, replacing tubing and flush solutions, or accessing the line for a blood sample. Thromboembolic Complications Occur with kink in catheter or when fluid flow through system is poor A blood clot can form at tip of the catheter. This blood clot could become dislodged during catheter repositioning or with flushing. Most thrombi clinically silent Risk Factors for thromboembolic complications Hypercoagulability associated with: Myocardial infarction Fever Polycythemia Vessel wall trauma (during insertion) Antithrombin Cancer Estrogen therapy Topic Six: Water vs. Pressure Transducer Monitoring Introduction Here we explore the taking of pressure measurements via different methods-pressure transducer and water manometer American Association of Critical-Care Nurses (AACN). All rights reserved.

39 Page of 8 39 Central Venous Pressure Measurement Using a Pressure Transducer Pressure transducer takes pressure measurements. CVP/RAP measurement may be taken from proximal port of any of these: Pulmonary artery catheter Single lumen catheter or multilumen catheter CVP/RAP Lumen will be attached to a transducer-pressure monitoring system. The pressure monitoring system is referenced to the phlebostatic axis (fourth intercostal space and midchest.) Pressure readings taken at end-expiration Water Manometer Before the advent of electronic pressure monitoring systems, water manometer systems were used to take pressure measurements. Today, rarely used in critical care but sometimes used outside ICU for patients experiencing fluid shifts. Measurements are taken in centimeters of water pressure (cm H 2 0). Zero Point of Water Manometer When using water manometer, the water manometer is placed level with the phlebostatic axis (fourth intercostal space and midchest.) Measurements are taken from the height of the water column in the manometer. Use this formula to convert a cm H 2 0 reading to mmhg: 1 cm H = mmhg 2008 American Association of Critical-Care Nurses (AACN). All rights reserved.

40 40 Page 1 of 3 Preventing Catheter Related Lesson: Central Venous Pressure Monitoring Bloodstream Infection Topic: Insertion of Central Catheters-Sites and Techniques Practice Alerts The goal of the practice alerts is to help nurses and other health care practitioners carry their bold voices to the bedside to directly impact patient care. Practice alerts are succinct, dynamic directives from AACN that are supported by authoritative evidence to ensure excellence in practice and a safe and humane work environment. Practice Alerts are short directives designed for easy reference. AACN will issue practice alerts to: Close research/practice gap Provide guidance Standardize practice Identify/inform about new advances/trends Recognizing that practice is dynamic, the Practice Alerts will be reviewed and updated as needed, and can be accessed by going to: Following is the current Practice Alert for Preventing Catheter Related Bloodstream Infection, but be sure to check the link for the most up-to-date information.

41 41 Page 2 of 3 PREVENTING CATHETER RELATED BLOODSTREAM INFECTION Expected Practice: Cleanse hands with waterless cleaning solution or, if visibly soiled, with soap and water before and after patient contact. Disinfect clean skin utilizing friction with an appropriate antiseptic (preferably 2% chlorhexadine) before catheter insertion and during site care. Utilize full barrier precautions when inserting central venous access devices. Educate all staff inserting and caring for intravascular catheters, assess competency of same at regular intervals, advocate adherence to standards of care. Replace peripheral IV sites in the adult patient population at least every 96 hours but no more frequently than every 72 hours. Leave peripheral venous catheters in children until IV therapy is completed, unless complications (e.g., phlebitis and infiltration) occur. Replace IV tubing at least every 96 hours but no more frequently than every 72 hours. When adherence to aseptic technique during intravascular catheter insertion cannot be ensured (i.e. prehospital, code situation), replace the catheter soon as possible, but within 48 hours. Supporting Evidence: A substantial proportion of hospital-acquired infections result from cross-contamination from the hands of healthcare workers. Alcohol-based hand rub, compared with traditional handwashing with unmedicated soap and water or medicated hand antiseptic agents, may offer better results because it requires less time, acts faster, and is less likely to irritate skin. Thus, the CDC recommends the use of alcohol-based hand rubs between patient contacts as an adjunct to traditional handwashing alone. Chlorhexidine gluconate solutions utilized for vascular catheter site care reduce catheter related bloodstream infections and catheter colonization more effectively than povidone-iodine solutions. Moreover, 80% of resident and transient skin flora are found in the first five epidermal layers of the skin. There is clinical evidence to support the efficacy of applying antiseptics with sufficient friction to assure that the solution reaches into the cracks and fissures of the skin. There is no evidence that supports use of traditional concentric prepping technique. Although a 2% chlorhexidine-based preparation is preferred, tincture of iodine, an iodophor, or 70% alcohol can be used. Allow any solution used to dry before the catheter is inserted. Compared with peripheral venous catheters, CVCs carry a substantially greater risk for infection; therefore, the level of barrier precautions needed to prevent infection during insertion of CVCs should be more stringent. Maximal sterile barrier precautions (e.g., cap, mask, sterile gown, sterile gloves, and full body sterile drapes) during the insertion of CVCs substantially reduce the incidence of CRBSI compared with standard precautions (e.g., sterile gloves and small drapes) 1,3,2,10 There are some studies that demonstrate infection rates are lower when the

42 42 Page 3 of 3 subclavian site is used. Selection of central line insertion site, however, is based on patient risk factors. Healthcare workers who insert and care for intravascular devices should receive formalized education and training in indications for intravascular catheterization, proper placement, maintenance, and infection control. Educational programs focusing on central venous catheter insertion and care have lead to a substantial decrease in cost, morbidity, and mortality attributable to central venous catheterization. Ongoing education and reinforcement of appropriate technique serve as a reminder of current best practices, and studies demonstrate that consistent reinforcement of aseptic technique leads to decreased CRBSI. Studies of peripheral intravenous catheters show that there is not a substantial difference in phleblitis rates between catheters left in place 72 hours and those left in place 96 hours. There is no evidence to support that routine replacement of central venous catheters is more effective in decreasing blood stream infections than replacing central venous catheters as needed. Studies show that IV tubing containing crystalloids can be replaced every hours. If monitoring using a transducer system, replace the transducer, tubing, flush device and flush solution every 96 hours. What You Should Do: Ensure that your units have written practice documents such as a policy, procedure or standard of care that include use sterile technique with full barrier precautions when central venous access devices are inserted. Ensure that your units have written practice documents such as policy, procedure or standard of care that address frequency of peripheral IV site rotation and tubing change. Establish a process for education and routine evaluation of all staff inserting and caring for intravascular devices. Review your unit s rate of catheter related blood stream infection rate and if needed establish an interdisciplinary team, including but not limited to staff nurse, advance practice nurse, infection control nurse (officer), and a physician. Develop a process for daily evaluation for need of any central venous catheters. Need More Information or Help? Talk with a clinical practice specialist for additional information / assistance at then select PRN.

43 43 Page 1 of 1 Rhythm Strip and ECG Lesson: Central Venous Pressure Monitoring Topic: Waveform Analysis and Clinical Applications

44 44 Checklist Sample Lesson: Central Venous Pressure Monitoring Topic: Complications Central Line Procedural Checklist

45 45 The Essentials of Lesson: Central Venous Pressure Monitoring Hemodynamic Monitoring Topic: Catheter Types Practice Pearls Types of Central Venous Catheters Central venous catheters can be used to obtain blood samples, administer different medications simultaneously, administer total parenteral nutrition (TPN) and obtain CVP measurements.

46 46 The Essentials of Lesson: Central Venous Pressure Monitoring Hemodynamic Monitoring Topic: Insertion of Central Catheters Sites and Techniques Evidence Based Interventions Prior to insertion of any central venous catheter, including a pulmonary artery catheter, collect all supplies including the sterile tray holding the catheter as well as sterile gown, gloves and mask for the person inserting the catheter. Usually the tray containing the catheter will contain a large sterile drape, the prep solution for cleansing the area as well as a local anesthetic, syringes, needles, gauze dressings, and other supplies. Most Common Insertion Sites for Central Venous Catheters The subclavian approach should be avoided in any patient with a coagulopathy or thrombocytopenia due to the inability to apply compression if the Subclavian artery is punctured. One should never allow the system to be open. If the patient inhales, a large amount of air could be sucked into the catheter and the vein resulting in an air embolus. The left IJ and left subclavian are often avoided because of the risk of puncturing the thoracic duct, located at the junction of the left IJ and left subclavian vein. Puncturing the duct can result in lymph fluid leaking into the pleural space causing a hydrothorax.

47 47 The Essentials of Lesson: Central Venous Pressure Monitoring Hemodynamic Monitoring Topic: Managing Central Venous Catheters After Insertion Catheter Procedures In many multilumen central venous catheters the brown port is the distal port. The distal port should be used for CVP monitoring, blood administration, high-volume fluids and medication administration. The blue port is the medial port and should be used for TPN administration or medication administration. When inserting a central venous catheter, if TPN administration is anticipated, the distal port should be used for medication administration. The white port is the proximal port. This port should be used for blood sampling, medication administration and blood administration. You will need to validate these with the product used in your facility.

48 48 The Essentials of Lesson: Central Venous Pressure Monitoring Hemodynamic Monitoring Topic: Waveform Analysis and Clinical Applications Elevated and Decreased CVP/RAP In the critically ill patient, a low CVP/RAP may indicate hypovolemia. The physician may order volume to be administered by IV to achieve a target CVP of 10 to 14 mmhg. The reliability of the CVP/RAP reading to accurately reflect the intravascular volume is limited by the compliance of the right ventricle. If the right ventricle becomes less compliant (occurs with right ventricular failure and ischemia), the CVP/RAP will be increased because more pressure is required to eject the RA volume into the RV. One must always assess the patient s entire clinical picture to determine the reliability of the pressure measurement and intravascular volume.

49 49 The Essentials of Lesson: Central Venous Pressure Monitoring Hemodynamic Monitoring Topic: Complications Bleeding Always assess the abdominal girth as well as the softness of the abdomen. If retroperitoneal bleeding is present, the abdomen will become very taught and the girth will increase. Patients often will complain of severe back pain. Nosocomial Infection Most facilities have a central line bundle which consists of mandatory steps/processes to be used during insertion of a central line. The purpose is to prevent a central line infection. Ask about your hospital s central line bundle. Thromboembolic Complications Avoid forceful flushing with a syringe which may cause the thrombus to become dislodged.

50 Lesson 4 Pulmonary Artery Catheters Included in this Lesson: Indications For PA Catheter Catheter Types Insertion Managing And Troubleshooting PA Catheters Waveform Analysis Complications And Associated Problems Clinical Applications

51 51 Lesson Objectives Module: Hemodynamic Monitoring Lesson: Pulmonary Artery Catheters Upon completion of this lesson you will be able to: Discuss the indications for, contraindications of, and general management principles for pulmonary artery catheters. Identify the characteristics of normal and abnormal pulmonary artery pressure waveforms. - Identify various types of PA catheters, indications and contraindications - Describe PA catheter insertion procedure and nursing considerations - Describe PA catheter insertion procedure and nursing considerations - Describe management and nursing implications of PA catheters - Identify complications of PA catheters and how to troubleshoot them - Identify the components of the pulmonary arterial and pulmonary capillary wedge pressure waveform - Discuss the clinical applications of pulmonary artery pressure monitoring

52 Page of 9 52 Lesson Takeaway - Pulmonary Artery Catheters Topic One: Indications for PA Catheter Introduction In this lesson we focus on the pulmonary artery catheter (PA catheter) and discuss types, insertion responsibilities, and indications for use. For patients with a PA catheter, interpreting waveforms and documenting values, troubleshooting the system, and assessing for complications are priorities. Value of Pulmonary Artery Catheters The value of a PA catheter: A single catheter placed in the right heart can: Measure pressures directly in the right heart Measure pressures indirectly from the left heart. A continuous chamber is result of the opening of valves during diastole. In patients with normal pulmonary vasculature, mitral valve, and left ventricular function, the PAD and PAOP reflect the left ventricular end-diastolic pressure. Left ventricular end-diastolic pressure important for evaluating left ventricular function/prognosis. Challenges to Widespread Use History of pulmonary artery catheter Steady decline in use and a search for new methods of obtaining cardiac output have occurred since 1986 when a multisite study denounced their use. Some of these newer and minimally to noninvasive methods for obtaining information to assist in management of critically ill are looked at in next lesson. Assessment of Cardiovascular Status Today, PA catheter generally used: In patients not responding well to traditional therapy For assessing cardiovascular status and response to therapeutic interventions in complicated myocardial infarction cases like those where patient: Develops cardiogenic shock Develops congestive heart failure Has structural defects -Acute ventricular septal defect -Valvular abnormalities -A right ventricular infarction Use in Cardiovascular context Use in Pulmonary context Use in Obstetric context Use in Monitoring 2008 American Association of Critical-Care Nurses (AACN). All rights reserved.

53 Page of 9 53 Fluid Perioperative Use in preventing/treating Shock Topic Two: Catheter Types Introduction Here we explore different types of PA catheters. Triple-Lumen Thermodilution Catheter First type of PA catheter available Thermistor near its tip to measure changes in core temperature 3 Lumens: One is at level of the right atrium and measures RAP and CO Second one terminates in the pulmonary artery and measures PAP Third one is also in the pulmonary artery and measures PAOP or wedge PAOP obtained using the attached syringe to inflate balloon-tipped port with up to 1.5 ml of air. Other Types of PA Catheters Four-lumen Thermodilution Catheter Mixed Venous Oxygen Saturation Catheter Pacing Thermodilution Catheter Topic Three: Insertion Introduction Here we look at insertion methods for a PA catheter. Relative Contraindications No known absolute ones but relative ones are: Presence of fever, mechanical tricuspid valve, and anticoagulated state Patients with Wolff, Parkinson, White syndrome, and Ebstein malformation Have risk for tachydysrhythmias Closely monitor the ECG in patients with left bundle branch block. Have increased risk of complete heart block In case that heart block develops, emergent pacemaker insertion may be necessary American Association of Critical-Care Nurses (AACN). All rights reserved.

54 Page of 9 54 Equipment Preparation Nurse responsibility to prepare equipment including the pressure tubing system, transducer, and monitoring system To ensure accuracy, setting the scales for pressure tracing is important. Procedure for setting the scales PA Catheter Insertion Gather and prepare supplies and equipment (steps): Infection prevention Gather supplies Connect Calibrate fiberoptics Check balloon Also vital to determine patient s baseline cardiovascular, peripheral vascular and neurovascular status. Assisting With PA Catheter Insertion May be inserted through subclavian, internal jugular, femoral, external jugular, or antecubital vein. Subclavian (instead of jugular or femoral) best for infection prevention Validation of PA catheter placement Done by waveform analysis Correct if a PAOP tracing exists when balloon is inflated and a PA tracing exists when balloon is deflated. Verified by chest x-ray. PA Catheter Specs Procedure Saline IV Steps of PA catheter insertion: Advance Catheter Inflate Balloon Distinct Waveforms Pressure Monitored Dual-channel Strip 2008 American Association of Critical-Care Nurses (AACN). All rights reserved.

55 Page of 9 55 Advance Catheter Continuous PAP Waveform Monitoring PAP waveform requires continuous monitoring because catheter may become wedged in pulmonary artery or slip back into right ventricle, leaving patient at risk for pulmonary infarction or ventricular dysrhythmias. Procedure for attempting a dislodge Bedside nurse should not advance a PA catheter. Daily Inspection of the Catheter Insertion Site Catheter insertion site needs daily inspecting erythema, drainage, or swelling. Clean insertion site and apply an occlusive dressing. Fluoroscopy or Chest x-ray to Confirm Catheter Position Catheter position requires confirmation by fluoroscopy or chest x-ray. (Chest x-ray also rules out pneumothorax and kinking of the catheter.) Use a lateral chest film. Topic Four: Managing and Troubleshooting PA Catheters Introduction Here we look at ways to get accurate readings, manage the PA catheter, and troubleshoot it when it s not accurate or functioning properly. Patient Positioning Helps get accurate PA pressure measurements Position patient in supine position with the head of bed elevated from 0 to 60 degrees. Ensure air/fluid interface is level with phlebostatic axis. Reposition transducer. When patient in a side-lying or prone position, phlebostatic axis is not at the fourth ICS, midclavicular. For patient in right lateral position, reference point is intersection of the fourth intercostal space and the midsternum American Association of Critical-Care Nurses (AACN). All rights reserved.

56 Page of 9 56 For patient in left lateral position, reference point is intersection of the fourth intercostal space and the left parasternal border. Inaccurate Pressure Interpretations Factors that can cause distortion: Catheter obstruction (clots, air or blood, catheter bending) Excessive tubing or connectors Loose connections Transducer damage To ensure accuracy, perform the dynamic response testing (square wave test) on regular basis. End-expiration Hemodynamic Values Hemodynamic values taken end-expiration since that is when: Atmospheric and alveolar pressures are approximately equal Pulmonary pressures have minimal effect on intracardiac pressures (thereby allowing for a more accurate value) In a patient breathing spontaneously, pleural pressure decreases during inspiration. The pressure waveform elevates during expiratory phase. Readings should be documented at the peak pressure. Pressure Readings in the Mechanically Ventilated Patient In a mechanically ventilated patient, pleural pressure increases as the breath is delivered by the ventilator. Therefore, in this case, it is the intracardiac pressures that are more consistent and accurate. Readings should be documented at the lowest point in the tracing. PA Pressure Accuracy vs. Location of Catheter Tip Properly locating the catheter tip also helps accuracy. Place catheter tip below left atrium in lung zone 3. Aspects of proper catheter tip placement: Pulmonary Zone Tip Migration Tip Placement Validation by Waveform 2008 American Association of Critical-Care Nurses (AACN). All rights reserved.

57 Page of 9 57 Positive End Expiratory Pressure (PEEP) Greater than 10 cm H 2 O A PEEP greater than 10 cm H 2 O increases alveolar and intrathoracic pressure, compresses pulmonary vasculature, and affects PAOP measurement accuracy. Question accuracy of PA measurements if/when: Significant respiratory variation present with the PAOP waveform PAOP > PAD Gradient between PAD and PAOP is greater than 4 mmhg Evidence-Based Practice: Pulmonary Artery Pressure Measurement: AACN s 2004 Practice Alert on PA pressure measurement provides guidelines for improving accuracy of PA catheter measurements: Perform square wave test at beginning of each shift. Position patient supine with HOB elevation from 0 to 60 degrees. Use phlebostatic axis as reference point for leveling. Obtain measurements from a graphic tracing at end-diastole. Troubleshooting Important for maintaining catheter patency, ensuring that data from PA catheter is accurate, and preventing occurrence of catheter-related and patient-related complications. Possible reasons why waveform may not be displaying on the monitor: Catheter has kink. Stopcock not correctly positioned. An incorrect scale size was chosen. Flush bag is empty or there is less than 300 mmhg of pressure on the pressure bag. Catheter is clotted. Cable may be fractured and need replacing. (rare) Other Issues Other possible reasons for an inaccurate or absent PA reading on the monitor: Artifact Blood back-up in line Inability to flush catheter Ruptured balloon Continuous wedge waveform (a medical emergency) 2008 American Association of Critical-Care Nurses (AACN). All rights reserved.

58 Page of 9 58 Topic Five: Waveform Analysis Introduction Here we explore the process of interpreting waveforms. Pressure Waveform Changes in Relation to Catheter Location Changes as catheter floats through right ventricle, across pulmonic valve, and out to pulmonary artery Obvious change in diastolic pressure Monitoring of systolic pressure values will not alert nurse if PA catheter is in the right ventricle. Monitoring of diastolic pressure values will alert nurse if PA catheter is in the right ventricle. Pulmonary Artery Pressure (PAP) Components: Peak systolic pressure, dicrotic notch, and end diastole. PAD (PA Diastolic) PAS (PA Systolic) Normal range: 15 to 25 mmhg Is generally equal to the right ventricular systolic pressure Dicrotic Notch PAOP (PA Occlusion Pressure) PVR (Pulmonary Vascular Resistance) LVEDP (Left Ventricular End-Diastolic Pressure) Identifying PA Peak Using the ECG Locate peak systole within the T wave and measure this value. Then locate end-diastole at the end of the QRS complex and measure this value. Pulmonary Artery Occlusion Pressure (PAOP) An indirect measure of left atrium pressure The waveform has characteristics similar to that of the RAP/CVP. Balloon Inflation Causes Waveform Change Causes waveform to change from a PA waveform to an atrial waveform with characteristic A and V waves American Association of Critical-Care Nurses (AACN). All rights reserved.

59 Page of 9 Components of the PA waveform: Mean Value PAOP A Wave V Wave Left Atrial Pressure Measuring Mean PAOP Locate the A wave near or after the QRS complex. Measure the top and bottom of the A wave and average the values. Topic Six: Complications and Associated Problems Introduction Here we explore some of the complications that can arise with PA catheters either during insertion or during maintenance. Complications Associated with PA Catheters Complications can occur during insertion or during maintenance. Potential complications: Arterial Puncture Air Embolus Pneumothorax Ventricular Ectopy Kinking or Knotting Complications of PA Catheter Monitoring Potential complications during maintenance: Pulmonary Rupture Pulmonary Infarction Infection Thrombosis Topic Seven: Clinical Applications Introduction Here we look at how monitoring the waveforms not only helps ensure that the catheter is still properly placed, but also aid in the diagnosis of cardiac and pulmonary diseases. We look at the implication of both PA pressures and elevations in certain wave types can mean to for diagnosing a patient. RAP, PAP, and PAOP Waveforms Some diseases cause abnormal waveform morphology American Association of Critical-Care Nurses (AACN). All rights reserved.

60 Page of 9 60 PA Pressure vs. Systemic Pressure PA pressures are critical for assessing whether there is adequate gas exchange in the lungs. PA pressures are low in comparison to systemic pressures. Normal pulmonary artery systolic pressure: mmhg Normal pulmonary artery diastolic pressure: 8-15 mmhg If pressure in pulmonary vasculature elevates, capillary hydrostatic pressure exceeds capillary osmotic pressure and forces fluid out of vessels. PAD vs PAOP For blood flow through lungs to occur, mean PA pressure must always be higher than left atrial pressure. PAD pressure should be higher than left atrial pressure (PAOP) and if it isn t, it usually means either a very low pulmonary blood flow state or the waveform has been misinterpreted. Reduce possible pulmonary complications by using the PAD to depict PAOP. Conditions that make PAD not equal to PAOP: Pulmonary diseases that increase the PVR Mitral valve diseases Rapid heart rates that decrease filling time causing PAD to elevate with no change in PAOP Analyzing Elevated PA Pressures Measuring PA pressures can help diagnose conditions. Elevated PA pressures occur in: Pulmonary hypertension Mitral valve disease Chronic pulmonary disease LV failure Waveform analysis, too, can help diagnose conditions. Large A waves seen in patients with: Mitral stenosis Severe LV failure Ventricular demand pacing PVCs Hypoxia Pulmonary emboli Large V waves seen in patients with mitral insufficiency. Elevated A and V waves seen in patients with: Cardiac tamponade Constrictive pericardial disease Hypervolemia 2008 American Association of Critical-Care Nurses (AACN). All rights reserved.

61 61 Supply Checklist Lesson: Pulmonary Artery Catheters Topic: Insertion As the critical care nurse, you will need to gather all the supplies and equipment for the insertion of the PA catheter. Below is a sample supply checklist. PA catheter (nonheparin-coated PA catheters are available) Percutaneous sheath introducer kit and sterile catheter sleeve Pressure modules and cables for interface with the monitor Cardiac output cable with a thermistor/injectate sensor Pressure transducer system, including flush solution recommended according to institution standard, a pressure bag or device, pressure tubing with flush device, and transducers Dual-channel recorder Sterile normal saline intravenous fluid for flushing the introducer and catheter infusion ports Antiseptic solution (e.g., 2% chlorhexidine-based preparation) Caps, fluid-shield masks, sterile gowns, sterile gloves, nonsterile gloves and sterile drapes 1% lidocaine without epinephrine Sterile basin or cup Sterile water or normal saline Sterile dressing supplies Stopcocks (may be included in some pressure tubing systems) Nonvented caps for stopcocks Additional equipment as needed includes the following: Fluoroscope Emergency equipment Temporary pacing equipment Indelible marker Transducer holder

62 62 Page 1 of 5 Pulmonary Artery Pressure Lesson: Pulmonary Artery Catheters Measurement Topic: Managing and Troubleshooting PA Catheters Practice Alerts The goal of the practice alerts is to help nurses and other health care practitioners carry their bold voices to the bedside to directly impact patient care. Practice alerts are succinct, dynamic directives from AACN that are supported by authoritative evidence to ensure excellence in practice and a safe and humane work environment. Practice Alerts are short directives designed for easy reference. AACN will issue practice alerts to: Close research/practice gap Provide guidance Standardize practice Identify/inform about new advances/trends Recognizing that practice is dynamic, the Practice Alerts will be reviewed and updated as needed, and can be accessed by going to: Following is the current Practice Alert for Pulmonary Artery Pressure Measurement, but be sure to check the link for the most up-to-date information.

63 63 Page 2 of 5 PULMONARY ARTERY PRESSURE MEASUREMENT Expected Practice: Verify the accuracy of the transducer-patient interface by performing a square waveform test at the beginning of each shift. Position the patient supine prior to PAP/RAP (CVP) measurements. Head of the bed (HOB) elevation can be at any angle from 0 (flat) to 60. th Level the transducer air-fluid interface to the phlebostatic axis (4 ICS/½ AP diameter of the chest) with the patient in a supine position prior to PAP/RAP measurements. Obtain PAP/RAP measurements from a graphic (analog) tracing at end-expiration. Use a simultaneous ECG tracing to assist with proper PAP/RAP waveform identification. PA catheters can be safely withdrawn and removed by competent registered nurses. Supporting Evidence: The square waveform test, or dynamic response test, determines the ability of the transducer system to correctly reflect pressures in the pulmonary artery. 1-5 This test can identify system problems, such as air bubbles in the tubing, excessive tubing length, loose fitting equipment, and/or patient problems, such as catheter patency. Any of these problems may affect accuracy of PAP/RAP measurements and should be corrected prior to pressure measurement. Experts recommend the following situations as appropriate to perform the square waveform test: on the initial system setup, at least once each shift, after opening the catheter system (e.g. for rezeroing, drawing blood, or changing tubing), and whenever the PAP waveform appears to be damped or distorted. 1-4,6 Consider the following changes in PA pressures as clinically significant (i.e., not reflective of the normal variability in PA pressures): PAS > 4-7 mm Hg; PAEDP > 4-7 mm Hg; PAWP > 4 mm HG. 7,8 Studies in a variety of patient populations have found that PAP/RAP measurements are accurate when the head of the bed is elevated to any angle between 0 o and 60 o, as long as the patient is in the supine position Two studies have also shown that PAP/RAP readings are accurate with the patient in a lateral position if the angle of rotation is exactly 30 or 90 with the head of the bed flat, and the location of the transducer air-fluid interface changed to the appropriate external landmarks for lateral positioning (30 o lateral: ½ distance from surface of bed to the left sternal border; 90 o right lateral: 4 th ICS/midsternum; 90 o left parasternal border). 1,12-14 When utilizing a 30 o side lying angle a method of ensuring an accurate angle is needed and should be readily available to the bedside practitioner. 13 Leveling the transducer air-fluid interface to the left atrium corrects for changes in hydrostatic pressure in vessels above and below the heart. 1,3 In the supine position, the external landmark for th 15,16 the left atrium is the phlebostatic axis (4 ICS/½ AP diameter of the chest). Studies have found that improper positioning of the air-fluid interface can lead to significantly different PAP/RAP reading. 17,18 Once the correct location for the phlebostatic axis is identified, a mark should be

64 64 Page 3 of 5 placed on the chest wall and a laser pointer level or a carpenter s level should be used to properly level the transducer air-fluid interface anytime the patient is repositioned. 1,2.,18 Changes in patient position, even slight HOB or, require releveling of the transducer air-fluid interface before obtaining PAP/RAP measurements. Changes in intrathoracic pressure during respiration significantly alter hemodynamic pressures. Obtaining accurate PAP/RAP measurements requires reading pressure waveforms during end expiration only. 1-4,9,19 Digital readouts on pressure monitors reflect pressures obtained throughout respiration and are significantly different from end expiratory pressures, requiring pressure to be read from graphic waveform tracings. 6,20,21 Levels of evidence supporting validation of PAP/RAP waveform measurement with simultaneous ECG tracings include clinical literature, expert opinion and sound theoretical principles of hemodynamic measurement. 1-4 Studies and surveys show that after education and clinical monitoring to assess competency, registered nurses can safely withdraw and/or remove PA catheters. 22,23,24 Before incorporating withdrawing and/or removing PA catheters into nursing practice, verify that it is within your state s scope of practice for registered nurses. What You Should Do: Always identify and mark the phlebostatic axis, obtain PAP/RAP with the patient in the supine position and the head of the bed elevated between 0 and 60 degrees, read pressures from a graphic (analog) recording at end expiration, and periodically perform a square waveform test. Assure that your critical care unit has written practice documents such as a policy, procedure or standard of care, that include these expected practice alert standards. Determine your unit s rate of compliance with these Practice Alert standards. 13 If compliance is < 90%, develop a plan to improve compliance : Consider forming a unit task force to address the need for changes in PAP/RAP measurement practices. Educate staff about the inaccuracies which can occur in PAP/RAP measurements with improper techniques (Education Toolbox) Incorporate content into orientation programs, initial and annual competency verifications. Develop a variety of communication strategies to alert and remind staff of the importance of these PAP/RAP practices. Create an audit tool for measuring compliance with PAP/RAP expected practice standards Need More Information or Help? A web based educational program on pulmonary artery pressure measurement is available at PAP/RAP Practice Alert information at Test of PA catheter knowledge Square waveform test information Identifying correct PAP/RAP waveforms from simultaneous pressure and ECG tracings Identifying correct phlebostatic axis location for leveling transducers in the supine position Power Point slide program for PAP/RAP measurement education sessions Talk with a clinical practice specialist for additional information / assistance ( then select PRN.

65 65 Page 4 of 5 REFERENCES: 1. Keckeisen M, Chulay M, Gawlinski A, eds. Pulmonary and artery pressure monitoring. In AACN s Protocols for Practice: Hemodynamic Monitoring Series. Aliso Viejo, Calif: AACN; Quaal S. Quality assurance in hemodynamic monitoring. AACN Clin Issues. 1993;4: Daily E, Schroeder J. Techniques in Bedside Hemodynamic Monitoring. St Louis, Mo: Mosby- Year Book; Quaal S. Ask the experts. Crit Care Nurse. 1995;10: Gardner R. Direct blood pressure measurement: Dynamic response requirements. Anesthesiology. 1981;54: Ahrens T, Penick J, Tucker M. Frequency requirements for zeroing transducers in hemodynamic monitoring. Am J Crit Care. 1995;4: Moser D, Woo M. Normal fluctuation in pulmonary artery pressure and cardiac output in patients with severe left ventricular dysfunction abstract. Am J Crit Care. 1996;5: Nemens EJ, Woods SL. Normal fluctuations in pulmonary artery and pulmonary capillary wedge pressure in acutely ill patients. Heart Lung. 1982;11: Dobbin K, Wallace S, Ahlberg J, et al. Pulmonary artery pressure measurement in patients with elevated pressures: effect of backrest elevation and method of measurement. Am J Crit Care. 1992;1: Wilson A, Bermingham-Mitchell K, Wells N, et al. Effect of back position on hemodynamic and right ventricular measurements in critically ill adults. Am J Crit Care. 1996;5: Woods S, Mansfield L. Effect of body position upon pulmonary artery and pulmonary capillary wedge pressures in noncritically ill patients. Heart Lung. 1976;5: VanEtta D, Gibbons E, Woods S. Estimation of left atrial location in supine and 30 lateral position abstract. Am J Crit Care. 1993;2: Bridges EJ, Woods SL, Brengelmann GL, et al. Effect of the 30 degree lateral recumbent position on pulmonary artery and pulmonary artery wedge pressures in critically ill adult cardiac surgery patients. Am J Crit Care. 2000;9: Kennedy GT, Bryant A, Crawford MK. The effects of lateral body positioning on measurements of pulmonary artery and pulmonary wedge pressures. Heart Lung. 1984;13: Paolella L, Dortman G, Cronan J, et al. Topographic location of the left atrium by computed tomography: reducing pulmonary artery catheter calibration errors. Crit Care Med. 1988;16: Courtois M, Fattal P, Kovacs S, Tiefenbrunn A, Ludbrook P. Anatomically and physiologically based reference level for measurement of intracardiac pressures. Circulation. 1995;92: Kee L, Simonson J, Stotts N, Skov P, Schiller N. Echocardiographic determination of valid zero reference levels in supine and lateral positions. Am J Crit Care. 1993;2: Bartz B, Maroun C, Underhill S. Differences in midanteroposterior level and midaxillary level of patients with a range of chest configurations. Heart Lung. 1988;17: Ahrens T. The effects of mechanical ventilation on hemodynamic waveforms. Crit Care Clin North Am. 1991;3: Ahrens T, Schallom L. Comparison of pulmonary atery and central venous pressure waveform measurements via digital and graphic measurement methods. Heart Lung. 2001;30: Lipp-Ziff E, Kawanishi D. A technique for improving the accuracy of the pulmonary artery diastolic pressure as an estimate of left ventricular end-diastolic pressure. Heart Lung. 1991;20: Wadas TM. Pulmonary artery catheter removal. Crit Care Nurse. 1994;14;62-72.

66 66 Page 5 of Roundtree WD. Removal of pulmonary artery catheters by registered nurses: a study in safety and complications. Focus Crit Care. 1999;18: Zevola, DR, Maier B. Improving the care of cardiothoracic surgery patients through advanced nursing skills. Crit Care Nurse. 1999;19:34-44.

67 67 The Essentials of Lesson: Pulmonary Artery Catheters Hemodynamic Monitoring Topic: Insertion Practice Pearls Relative Contraindications When the decision to insert a PA catheter has been made, the physician will need to speak to the patient and family regarding the reason for insertion, overview of the procedure and possible complications. A signed informed consent is the ideal. In most instances the insertion is emergent and the preparation of the patient and family may be inadequate. It is important to take the time after the patient has stabilized to discuss the information with the family.

68 68 The Essentials of Lesson: Pulmonary Artery Catheters Hemodynamic Monitoring Topic: Managing and Troubleshooting PA Catheters Inaccurate Pressure Interpretations Check tubing from arterial line and PA catheter for extensions when the patient returns from OR. Anesthesia usually adds extension tubing allowing access during surgery. Remove any extensions, tighten connections and perform square wave test during postoperative assessment. Positive End Expiratory Pressure (PEEP) Greater than 10 cm H O 2 A corrected wedge should be calculated for all patients on PEEP greater than 10 cm H2O. Corrected PAOP = measured PAOP (PEEP)(.75)/2. If the measured PAOP = 22 mmhg and the PEEP = 25 cm H 2 O, what is corrected wedge? (25 x.75)/2 = 9; then 22 9 = 13 mmhg

69 69 The Essentials of Lesson: Pulmonary Artery Catheters Hemodynamic Monitoring Topic: Complications and Associated Problems Complications of PA Catheter Monitoring The pressure waveform from the distal tip should be monitored continuously and promptly withdrawn if a spontaneous PAOP waveform appears. Overinflation of the balloon should be avoided by carefully observing the PA waveform and only inflating the balloon with enough air to change the PA waveform to the PAOP waveform. If a PAOP waveform is seen with inflation of <1.25 ml of air, withdraw the catheter tip slightly. Limit inflation time to 10 to 15 seconds. Prolonged inflation and excessive balloon volume put too much tension on the vessel wall.

70 Lesson 5 Cardiac Output Monitoring Included in this Lesson: Factors Affecting Cardiac Output Methods Of Calculating CO Clinical Application Of CO Non-Invasive CO Monitoring

71 Page of 9 71 Lesson Takeaway - Cardiac Output Monitoring Topic One: Factors Affecting Cardiac Output Introduction In this lesson we learn that the most widely utilized pieces of information from the PA catheter are cardiac output (CO) and stroke volume (SV.) We look at the factors affecting CO, methods of calculating CO, and the clinical application of this information. We also briefly discuss the several newer methods for assessing cardiac function which arose out of a desire for a method that was safer and less invasive. Cardiac Output Cardiac Output (CO) one the two most widely utilized pieces of information from the PA catheter Understanding CO critical to assessing if cardiac function adequate CO is the amount of blood ejected by the ventricle each minute. Equals HR x SV Is measured in L/min. Normal CO: 4-8 L/min. Output Relative to Body Size The CO value should be assessed keeping body size in mind. Example: A CO of 4.0 L/min. might not be enough for an NFL football player to maintain tissue perfusion. Cardiac Index Cardiac Index (CI) is a better measure of cardiac function than CO and is the value that should be used to trend cardiac function. CI is CO adjusted to individual body size You divide CO by the individual s BSA (which you get from the Dubois Surface Area chart on the cardiac monitor.) CI is displayed on most monitors either continuously or at the time that CO is obtained. This value only accurate if person s height and weight were entered into the database to ensure accuracy of this value. Normal value for CI: L/min/m 2 Stroke Volume Stroke Volume (SV) one of the two most widely utilized pieces of information from the PA catheter Understanding SV critical to assessing if cardiac function adequate 2008 American Association of Critical-Care Nurses (AACN). All rights reserved.

72 Page of 9 72 SV is the amount of blood ejected with each contraction of the ventricle. Normal SV: ml/beat Is best to index it. Do so by dividing it by BSA. Normal SVI (SV indexed): ml/beat/m 2 SVI is another indexed parameter that will be displayed on the monitor. Possible causes for a low SV or SVI: Inadequate blood volume (hemorrhage) Impaired ventricular contractility (myocardial ischemia or infarction) Increased systemic vascular resistance or cardiac valve dysfunction (mitral insufficiency). Possible cause for an elevated SV or SVI: A low systemic vascular resistance Cardiac Output Represents Oxygen Delivery to Cells SV depends on preload, afterload, and contractility. Since CO is SV x HR, CO is determined by preload, afterload, contractility, and heart rate. CO offers a global representation of oxygen delivery to the cells. If CO abnormal, selecting the right intervention requires a look at each of its component parameters: Preload, afterload, contractility, and heart rate. Ventricular Filling vs. Ventricular Ejection Causes of low CO can be broken into 2 groups: Conditions causing inadequate ventricular filling Similar characteristic of all these conditions is diminished preload resulting in inadequate forward blood flow Rapid rate dysrhythmias Hypovolemia Mitral/tricuspid valve stenosis Conditions causing inadequate ventricular ejection Myocardial infarction Metabolic disorders Use of negative inotropic drugs Myocardial diseases such as myocarditis or cardiomyopathy Constrictive pericardial disease Cardiac tamponad Restrictive cardiomyopathy Mitral/ tricuspid insufficiency Conditions causing high resistance to ejection Increased Cardiac Output Causes of high CO (the two most likely) are increased heart rate and decreased afterload. Conditions that can cause higher CO are: Fever Sepsis Anemia Pregnancy Hyperthyroidism 2008 American Association of Critical-Care Nurses (AACN). All rights reserved.

73 Page of 9 73 Heart Rate and Rhythm Normal HR bpm. In a healthy individual, increased HR causes increased CO. In individuals with impaired cardiac function, the great reduction in atrial contribution to ventricular filling that comes with increased HR can have detrimental effects. Dysfunction Bradycardia Tachycardia Components of Cardiac Output Preload The force that stretches the ventricles during diastole The filling pressure of the ventricles at the end of diastole The amount of blood that fills the ventricles during diastole Afterload Vascular resistance; the resistance to ventricular emptying during systole The pressure/resistance that the ventricles must overcome in order for them to be able to open the aortic and pulmonic valves and pump blood into the systemic and pulmonary vasculature. Contractility The strength of the myocardial contraction The degree of myocardial fiber shortening Preload Clinical indicators for right and left ventricular preload Influences on preload Reasons for reduced preload Reasons for increased preload Afterload Influences on afterload Reasons for reduced afterload Reasons for increased afterload Calculating Afterload Afterload cannot be measured directly; it must be calculated using values from the PA catheter American Association of Critical-Care Nurses (AACN). All rights reserved.

74 74 Lesson Objectives Module: Hemodynamic Monitoring Lesson: Cardiac Output Monitoring Upon completion of this lesson you will be able to: Discuss the indications for, contraindications of, and general management principles for cardiac output testing - Describe factors affecting Cardiac Output - Describe the methods for obtaining and calculating cardiac output - Discuss the clinical application of cardiac output - Describe non-invasive means of obtaining cardiac output

75 Page of 9 75 Clinical indicator of RV afterload is the PVR Both PAM and PAOP affect (correlate positively with both) PVR CO affects (correlates negatively with PVR Besides PAM, PAOP, and CO, another factor influencing afterload is hypoxia. Contractility Affected by many factors including: Preload and afterload Vasodilators, vasoconstrictors, and intropes Electrolyte levels Functioning of myocardium Myocardial oxygenation Factors increasing contractility: Fluid resuscitation Positive inotropic drugs Tachycardia Decreased afterload Factors decreasing contractility: Hypovolemia Negative inotropic drugs Myocardial ischemia Hypoxemia PEEP Electrolyte and acid base imbalances Intraabdominal hypertension Cardiac diseases Another method for identifying altered contractility in each ventricle: Right Ventricular Stroke Work Index (RVSWI) RVSWI = (PAD-RAP/CVP) SV/BSA (0.0136) Normal range: 7-12 g/m 2 /beat Left Ventricular Stroke Work Index (LVSWI) LVSWI = (MAP-PAD) SV/BSA (0.0136) Normal range: g/m 2 /beat 2008 American Association of Critical-Care Nurses (AACN). All rights reserved.

76 Page of 9 76 Topic Two: Methods of Calculating Cardiac Output Introduction Here we explore the different clinical methods for measuring cardiac output including Direct Fick, Dye Dilution, and Thermodilution. Clinical Methods for Measurement of Cardiac Output Different methods, each with strengths/weaknesses Direct Fick Dye Dilution Thermodilution (most commonly used) Direct Fick Method Requires calculating the oxygen consumed over a given period and measuring the oxygen concentration in venous and arterial blood. Most accurate method for CO measurement but not practical for routine use Use in situations where the thermodilution CO method cannot be used or when values obtained are suspect. Downsides: Invasive Accurate samples are sometimes difficult to obtain. Requires time for sample analysis Usually performed in cardiac catheterization suite Dye Dilution Method Involves injection of known quantity and concentration of indocyanine green or lithium into bloodstream then measuring the dye concentration at selected time intervals in order to calculate flow and volume CO is equal to the area under the indicator dilution curve. Though less cumbersome than Fick, has the problem that dye may recirculate and cause inaccuracies in subsequent measurements. Thermodilution Method At bedside, CO measurements obtained through PA catheter via one of these methods: Intermittent Bolus Thermodilution (TDCO) Continuous CO (C CO) Steps: TDCO injection Thermistor detects temperature change CO curve interpreted 2008 American Association of Critical-Care Nurses (AACN). All rights reserved.

77 Page of 9 77 If area under curve is large, indicates a low CO If area under curve is small, indicates a high CO. Controlling Variables Alleviates Erroneous Measurements In thermodilution method, you will want to take these measures in order to avoid erroneous results: Ensure forward flow of blood and adequate mixing of blood and injectate. Ensure that catheter is properly placed with the proximal port in the right atrium and the distal port in the pulmonary artery. TDCO Technique Xx A closed injectate delivery system is most often used for reasons of reducing multiple entries into the system and controlling infections. Iced injectate verses room temperature injectate A 10+ degree gradient between temperature of injectate and of patient s blood Cardiac output computer Proper Technique Use of proper technique and observing of CO curve will bolster accuracy. End-expiration Rapid injection Interpretation Abnormal curves Factors that can cause irregular cardiac output curves: Poor injectate mixing Changes in heart rate or blood Thermistor-vessel wall contact pressure Faulty technique Abnormal respiratory patterns Continuous Cardiac Output (CCO) Some PA catheters have continuous CCO capability (the ability to measure cardiac output continuously.) 2008 American Association of Critical-Care Nurses (AACN). All rights reserved.

78 Page of 9 78 Catheters with continuous CCO capability have a 10 cm thermal filament that emits a pulsed, low heat energy signal in a 30 to 60 second sequence. Proper placement: The thermal filament section of catheter is located in RV Bedside computer constructs thermodilution curves and measures CO automatically. Factors Affecting Accuracy of CO Values Adequate mixing Hyperthermia Infusions Ten-minute delay Topic Three: Clinical Application of Cardiac Output Introduction Here we look at the clinical application of CO and other values in assessing the hemodynamic status of the critically ill patient. Keys to Hemodynamic Assessment CO and CI: Assess blood flow SV and SVI: Help in assessment of pump performance RAP/CVP and PAOP: Assess cardiac filling pressures and give estimates of ventricular volume prior to preload or systolic ejection Hemodynamic Instability Presents as either a high blood flow state or a low blood flow state Body s efforts to compensate work only for a while. Low CO states occur due to hypovolemia or left ventricular dysfunction. Early warning of decreasing CO is a drop in the SV/SVI. CO will still appear normal even if this is dropped, so paying attention to this can help you anticipate and ward off a low CO or low-flow state. Low-flow State To treat a low CO state you must first determine whether it s hypovolemia or a problem of LV dysfunction. This is done by a combination of clinical and hemodynamic assessments: Patient s physical assessment 2008 American Association of Critical-Care Nurses (AACN). All rights reserved.

79 Page of 9 Patient s history Use of intracardiac pressures such as RAP, PAP and PAOP Abnormal PAOP Values Should be assessed with SV/SVI values to determine the clinical significance of the abnormality PAOP > 18 mmhg, especially if SV/SVI are low, usually reflects left ventricular impairment (and therefore something like congestive heart failure, myocardial infarction, cardiac tamponade, or cardiomyopathy) Elevated CO Values In healthy people, CO values elevate in response to increased oxygen demand. In critically ill patients, an elevated CO is always an indicator of some other problem. Elevated CO values can mean systemic inflammation, anaphylaxis, or neurogenic-mediated vasodilation, all of which result in a decreased SVR (afterload.) The increase in CO might be minimal or marked. The key to remember is that the CO elevation is a sign of a problem rather than the problem. Topic Four: Minimally Invasive and Noninvasive CO Monitoring Introduction Here we look at some of the more newly-developed and less invasive techniques for CO monitoring. However, despite these newer devices, CO monitoring using the PA catheter remains the standard, especially when data about cardiac filling pressures (RAP, PAP, PAOP) and mixed venous oxygen saturation are needed. Continuous Monitoring of the Central Circulation Can provide improved insights into normal physiology, pathophysiology and treatments for diseases. While invasive methods are well accepted, there is increasing evidence that these methods are neither accurate nor effective in guiding therapy. Hence the drive for other methods. Esophageal Doppler Cardiac Output The Esophageal Doppler uses sound to measure aortic blood flow velocity How it works (Doppler, transducer probe, and beam) 2008 American Association of Critical-Care Nurses (AACN). All rights reserved.

80 Page of 9 Contraindications: Coarctation of the aorta Esophageal pathology Coagulopathy IABP Pulse Contour Analysis SV is derived from the arterial pressure or the pulse waveform. Patients with poorly defined arterial waveforms or with arrhythmias that alter the waveform will not achieve reliable CO results with this method. Various types: PiCCO system LiDCO method Pulse Contour Wave Thoracic Bioimpedance Determines SV using a current that flows from an outer electrode to an inner sensor Thoracic bioimpedance: the relationship between impedance and SV The resistance of current flow (impedance) across the chest is inversely related to the thoracic fluid. A useful method for trend analysis, but not accurate enough for diagnostic interpretation Major application has been outside the critical care setting. Management of acutely ill patients in the outpatient setting may be the most important contribution of this technology. Gastric Tonometry Provides CO information based on adequacy of gastric mucosal perfusion. Gastric very sensitive to altered mucosal perfusion. Carbon dioxide partial pressure PCO 2 measured in the stomach or intestine. Sublingual Capnometry (PSLCO 2 ) An increase in PSLCO 2 directly and inversely correlates with a decrease in sublingual blood flow. Noninvasive method of identifying regional abnormalities in blood flow Only limitation: Its noncontinuous data collection Has been used to: Diagnose and quantify severity of circulatory shock, with predictive value of 100% Validate end-points of resuscitation. Predict hemodynamic stability: A PSLCO 2 measurement < 45 mmhg accurately predicts hemodynamic stability American Association of Critical-Care Nurses (AACN). All rights reserved.

81 81 The Essentials of Lesson: Cardiac Output Monitoring Hemodynamic Monitoring Topic: Methods of Calculating CO Practice Pearls Thermodilution Method The specific gravity of D5W is used in the formula to derive CO by the TDCO method. The use of saline can result in a 2% decrease in the TDCO measurement. Saline should be substituted if the patient s medical condition warrants it. TDCO Technique Iced injectate may be preferable to room temperature injectate in patients with poor forward blood flow, such as those with right ventricular failure, tricuspid stenosis or tricuspid insufficiency. These conditions make it difficult to get accurate cardiac output measurements, but the larger signal-to-noise ratio obtained with iced injectate may improve the estimates obtained with the thermodilution method. Hypothermic patients (cardiac surgery, trauma) may also require iced injectate to achieve greater accuracy and precision of measurement. The computation constant for the size and type of catheter used can be found in the package insert of the PA catheter. Factors Affecting Accuracy of CO Values Continuous CO monitoring does not reflect acute changes in the CO value since the updated value on the monitor display is an average of three to six minutes of data. Expect a delay of approximately 10 or more minutes to detect a change of 1 L/min in CO.

82 82 The Essentials of Lesson: Cardiac Output Monitoring Hemodynamic Monitoring Topic: Minimally Invasive and Noninvasive CO monitoring Esophageal Doppler Cardiac Output Sedation is required for the entire time the probe is in place.

83 83 Lesson 6 Oxygenation And Transport Included in this Lesson: Oxygen Supply And Demand Types Of Catheters (SVO2, Scvo2) Conditions Affecting Oxygen Monitoring Clinical Applications

84 84 Lesson Objectives Module: Hemodynamic Monitoring Lesson: Oxygen and Transportation Upon completion of this lesson you will be able to: Discuss the indications for, contraindications of, and general management principles for mixed venous oxygenation monitoring - Describe oxygen supply, demand and consumption - Identify the types of catheters and equipment required for monitoring systemic oxygenation - Discuss conditions that affect oxygenation and the body s compensatory mechanisms - Identify the clinical application of mixed venous oxygen monitoring - Describe the use of SVO2 and ScVO2 monitoring in the critically ill patient.

85 Page of 7 85 Lesson Take-away - Oxygen and Transport Topic One: Oxygen Supply and Demand Introduction In this lesson we learn that all the hemodynamic parameters we ve discussed are all part of a bigger picture-a balance, at the tissue level, between oxygen delivery and oxygen demand. We look here at types of catheters used to monitor mixed venous oxygen saturation, conditions affecting oxygen monitoring, and clinical applications of SVO 2 monitoring. Oxygen Delivery Goal of hemodynamic monitoring: Evaluate whether oxygen delivery to tissues is enough to meet their metabolic demands. If oxygen delivery not adequate, we must determine steps for enhancing this delivery. Adequate Oxygen Delivery Inadequate Oxygen Delivery Oxygen Demand Oxygen demand: Amount of oxygen cells require to meet their metabolic process Oxygen consumption: Amount of oxygen cells actually use Determinants of Oxygen Supply Diffused oxygen Blood oxygen content Oxygen transport Oxygen extraction Topic Two: Types of Catheters (SvO2, ScVo2) Introduction Here we review the clinical applications of SvO 2 and ScvO 2 monitoring. Oxygen Saturation of Blood Traditionally, a pulmonary artery catheter is used. Referred to as mixed venous oxygen saturation. A continuous measure possible by using a fiberoptic pulmonary artery catheter. An intermittent measure possible by obtaining mixed venous blood samples American Association of Critical-Care Nurses (AACN). All rights reserved.

86 Page of 7 86 More recently, central venous oxygen saturation has been reintroduced as a less invasive alternative to mixed venous oxygen saturation. Monitoring Mixed Venous Oxygen Saturation (SvO2) The oxygen saturation of the mixed venous blood (blood in the pulmonary artery) Varies as blood returns to right side of heart from various parts of body but gets mixed in the RV by the trabeculae so that the oxygen content uniform by time blood is ejected from the RV into the pulmonary artery. Tissue Oxygen Delivery vs. Oxygen Consumption Oxygen delivery/consumption similar to a train, the hemoglobin molecules as the boxcars that get loaded and offloaded over and over again. Venous oxygen: Amount of oxygen left after blood has passed through the tissues Oxygen Delivery (DO 2 ): Amount of oxygen delivered to tissues in 1 minute Important components -Hemoglobin (Hgb) -Arterial oxygen saturation (SaO 2 ) -Cardiac Output (CO) Formula is Hgb x 1.38 x SaO 2 x CO x 10 Venous oxygen transport: Amount of oxygen remaining after the blood has passed through the tissues Important components: -Hemoglobin (Hgb) -Venous oxygen saturation (SvO 2 ) -Cardiac Output (CO) Formula is Hgb x 1.38 x SvO 2 x CO x 10 Normal = 750 ml/min. Oxygen consumption (VO 2 ): Amount of oxygen extracted (consumed) at the tissue level. Is the difference between DO 2 and venous oxygen transport Formula is Hgb x 1.38 (SaO 2 -SvO 2 ) x CO x 10 Normal = 25% of DO 2 or 250 ml/min. VO 2 I is 125 ml/min/m 2 Mixed venous oxygen saturation (SvO 2 ): The difference between oxygen delivery and oxygen consumption. Provides information about the balance between oxygen delivery and consumption in tissue Represents the end result of tissue oxygen delivery and consumption Provides information about the oxygen reserve for the body Formula is DO 2 -VO American Association of Critical-Care Nurses (AACN). All rights reserved.

87 Page of 7 87 SvO 2 : Global Indicator of Oxygen Utilization SvO 2 a global indicator of oxygen utilization by body Rather than offering specific info about oxygen utilization by an organ, it tells the percentage of oxygen used by the body used and how much is left over. Changes in SvO 2 Can be due to changes in oxygen delivery or to changes in oxygen consumption Normal SvO 2 Range Is 60-80% Patient within normal range can still be in trouble. Better indicator: A 5-10% increase or decrease in the SvO 2 that lasts over 3-5 minutes. Body Compensation for Low Oxygen Supply In the event oxygen supply is inadequate to meet oxygen demands, body tries to compensate in these ways: Increasing cardiac output Autoregulation Anaerobic metabolism Monitoring Central Venous Oxygen Saturation (ScvO 2 ) ScvO 2 can be used as a surrogate for SvO 2 Is the incorporation of fiberoptics into continuous monitoring of the oxygen saturation of the superior vena cava ScvO 2 vs. SvO 2 : What is the difference between the two? SvO 2 measured using a pulmonary artery catheter ScvO 2 measured using a central venous catheter Normally the ScvO 2 and SvO 2 measures are the same, but in a critically ill patient with severe sepsis or shock, 2008 American Association of Critical-Care Nurses (AACN). All rights reserved.

88 Page of 7 88 ScvO 2 runs 5-13% (and an average of 7.5%) higher than SvO 2 ScvO 2 has been shown to track with SvO 2. ScvO 2 Tracks SvO 2 A ScvO 2 of 70% implies that SvO 2 is likely to be 60-65%. Fiberoptic Technology Used in both fiberoptic pulmonary artery catheter and fiberoptic central venous triple lumen catheter How the technology works: Fiberoptic network travels length of catheter. An optical module transmits light down length of the catheter. Hemoglobin absorbs a certain amount of light relative to oxygen saturation. The light is then reflected back to optical module where it is converted into an electrical signal and transmitted to the monitor. Insertion Guidelines Insertion guidelines for SvO 2 and ScvO 2 monitoring similar. In Vitro calibration Signal strength In Vivo calibration Transport considerations Topic Three: Causes of DO2/VO2 Imbalance Introduction Here we look at the conditions that can affect oxygen delivery and tissue oxygen demand, causing DO2/VO2 imbalances. DO 2 /VO 2 Imbalances Oxygen delivery can fall with any of these occurrences: Decreased hemoglobin Leftward shift of Decreased CO Oxyhemoglobin Saturation Decreased SaO 2 Curve Loss of autoregulation 2008 American Association of Critical-Care Nurses (AACN). All rights reserved.

89 Page of 7 89 Increased Tissue Oxygen Demand Tissue oxygen demand can increase with certain patient conditions: Surgical trauma (oxygen demand increases 10-30%) Multisystem organ dysfunction (oxygen demand increases 20-80%) Severe sepsis (oxygen demand increases %) Critically ill in the ED (oxygen demand increases 60%) Head injury-not sedated (oxygen demand increases 138%) Head injury-sedated (oxygen demand increases 89%) Large, full thickness burns (oxygen demand increases 100%) Oxygen Demand Factors Tissue oxygen demand can also increase with these general ICU factors: Dressing change (oxygen demand increases 10%) Bed bath (oxygen demand increases 23%) Each position change (oxygen demand increases 31%) Increased work of breathing (oxygen demand increases 40%) Shivering (oxygen demand increases %) Visitor (oxygen demand increases 22%) Chest X-ray (oxygen demand increases 25%) ET suctioning (oxygen demand increases 27-70%) Getting out of bed (oxygen demand increases 39%) Weight on a sling scale (oxygen demand increases 36%) Rise in body temperature (For every 1 degree centigrade body temperature is elevated there is a 10-13% increase in oxygen demand.) Inotropic infusions (oxygen demand increases 6-20%) Causes of Increased or Decreased SvO 2 Decreased SvO 2 Indicates that more oxygen is being extracted Possible causes of the decrease: Decreased delivery - Falling hemoglobin - Falling cardiac output - Falling SaO 2 Increased demand - Seizures, shivering - Pain - Increased activity - Hyperthermia Increased SvO 2 Indicates that less oxygen is being extracted 2008 American Association of Critical-Care Nurses (AACN). All rights reserved.

90 Page of 7 90 Possible causes of the increase: Increased delivery -Increased CO -Administration of blood products -Increased FiO 2 Decreased demand -Hypothermia -Relief of pain -Anesthesia -Sepsis: Demand increased Oxygen extraction inhibited -Wedging a pulmonary artery catheter SvO 2 will increase by 10-20% Mixed venous blood no longer flowing by the catheter. The light source is now reflected off arterialized blood. When the balloon is deflated, SvO 2 value will return to previous setting. Effects of SvO 2 While Suctioning a Patient Very important to hyperoxygenate patient before and after suctioning (so that SvO 2 doesn t fall so low that patient becomes very high risk for developing a lethal arrhythmia.) Effects of SvO 2 While Turning Patient SvO 2 declines with turning. Patient s efforts to compensate (return to prior SvO 2 level within 3-5 minutes) may fail. Important to hyperoxygenate the patient prior to turning and again immediately after turning since with turning comes increased oxygen demand. Hyperoxygenating also helps promote better gas exchange. Topic Four: Clinical Applications Introduction Here we look at the impact of the components of oxygen delivery. Prompt Restoration of Tissue Oxygen Delivery Prompt restoration of tissue oxygen delivery is only factor that s enjoyed improved outcomes in last 30 years, so important to incorporate this info into our clinical practice American Association of Critical-Care Nurses (AACN). All rights reserved.

91 Page of 7 91 Normal Patient How to calculate oxygen delivery for a patient: Given: - CO = 5.0 l/min - SaO 2 = 98% - Hgb = 15 g/dl - SvO 2 = 75% Calculate these values: Oxygen Consumption (VO 2 ) Oxygen Delivery (DO 2 ) O 2 Extraction (the percentage of the oxygen being delivered that is being consumed) VO 2 = CO x Hgb x 13.8 (SaO 2 - SvO 2 ), so VO 2 = 5 x 15 x 13.8 x ( ) DO 2 = CO x Hgb x 13.8 x SaO 2, so DO 2 = 5 x 15 x 13.8 x.98 O 2 Extraction = VO 2 / DaO 2, so O 2 Extraction = 238 / 1014 Note, this is a normal patient since the components of oxygen delivery are within normal limits since All of the Given values are within normal range All of the calculated values are within normal range: VO 2 is 238 ml O 2 /min DO 2 is 1014 ml O 2 /min O 2 Extraction is 23% Oxygen Extraction Ratio We extract 22-30% of the oxygen delivered to the tissues. To get an actual estimate of this percentage, calculate the Oxygen Extraction Ratio (O 2 ER). O 2 ER = the difference between patient s SaO 2 or pulse oximetry (if a good reading present) and his/her SvO 2 value -SaO 2 represents the supply side. -SvO 2 represents the remaining amount of oxygen after blood passes through the tissues. Continuous SvO 2 Monitoring Critical care nurses must always be assessing patient for threats to oxygen delivery and cellular oxygen consumption. Continuous SvO 2 monitoring helpful in variety of situations: Management of patients with pulmonary disease Ventilator weaning Accidental disconnection from an oxygen source Development of a spontaneous pneumothorax Hypoxemia Suctioning Post cardiac surgery patients Trauma and high risk surgical patients American Association of Critical-Care Nurses (AACN). All rights reserved.

92 92 Obtaining a Mixed Venous Lesson: Oxygenation and Transport Blood Gas Sample Topic: Types of Catheters (SVO2, ScVo2) Steps for obtaining a mixed venous blood gas sample: 1. Attach a 5 ml syringe to the stopcock connected to the distal port of the PA catheter. 2. Turn the stopcock to off to the flush solution. 3. Begin withdrawing the blood sample very slowly. Aspirating quickly may result in arterialized blood being withdrawn into the catheter as well as air bubbles, causing an overestimation of the blood gas sample. 4. Once the discard volume is obtained and discarded, attach a heparinized syringe and withdraw 4-5 ml per hospital policy. 5. Turn the stopcock off to the sideport (open to the flush solution) and flush the catheter until free of blood. 6. Immediately cap the blood gas sample and place on ice. 7. Send to the laboratory.

93 93 Increased Tissue Oxygen Lesson: Oxygenation and Transport Demand Topic: Causes of DO 2/VO 2 Imbalance Situations That Cause an Increased Tissue Oxygen Demand Increased oxygen demand can be caused by specific patient conditions or by some general ICU factors. Patient conditions associated with an increased oxygen demand and the percent of increase include: 1. Surgical trauma 10-30% 2. Multisystem organ dysfunction 20-80% 3. Severe sepsis % 4. Critically ill in the Emergency Dept. 60% 5. Head injury-not sedated 138% 6. Head injury-sedated 89% 7. Large, full thickness burns 100% General ICU factors that increase oxygen demand and the percent of increase include: 1. Dressing change 10% 2. Bed bath 23% 3. Each position change 31% 4. Increased work of breathing 40% 5. Shivering % 6. Visitor 22% 7. Chest X-ray 25% 8. ET suctioning 27-70% 9. Getting out of bed 39% 10. Weight on a sling scale 36% 11. For every 1 degree centigrade the body temperature is elevated, there is a 10-13% increase in demand 12. Inotropic infusions 6-20%

94 94 Practice Exercise Lesson: Oxygenation and Transport Topic: Causes of DO /VO Imbalance 2 2 Calculate the total percent increase in oxygen demand for this patient: Consider that you are caring for an abdominal surgery patient. He is intubated and on a ventilator. You are preparing to bathe the patient at The following sequence of events occurs. 1. Bath is given and the patient is turned twice during the bath. 2. Three sets of dressings are changed. 3. Bed linens are changed and the patient is turned three times during the process. 4. The patient required suctioning after being turned and repositioned. 5. The patient s body temperature is 38 degrees centigrade. 6. At 5:30 am radiology is at the bedside to obtain the portable upright chest x-ray. In the process of positioning the plate behind the patient s back, his position is changed a total of three times. Upon completion of the x-ray, the plate is removed and the patient is repositioned. Event Percent Change Bed Bath 23% Position Change (x2) 31% Dressing Change (3 sets) 10% ET Suctioning 27-70% Body Temp. For every 1 degree centigrade the body temperature is elevated, there is a 10-13% increase in demand. Chest X-Ray 25% Getting Out of Bed 39% This patient s tissue oxygen demand increased by a total of 468%. General ICU nursing routines often follow this clinical scenario. The clinical issue that we must think about is related to the patient s ability to tolerate this increase in demand. Very often a patient will experience a cardiac arrest shortly after being turned, at change of shift in the morning after the bath has been given, or after the upright portable chest x-ray is taken and lab work drawn. The advantage of monitoring SvO 2 or ScvO2 continuously is that we have the ability to immediately see the impact of our nursing interventions on the patient.

95 95 Calculating Oxygen Delivery Lesson: Oxygenation and Transport Topic: Clinical Applications Let s take a look at how to calculate oxygen delivery for a patient. Note that the components of oxygen delivery are within normal limits. The SvO 2 is at 75%. Calculation of oxygen delivery reveals a DO 2 of 1000 ml O2/min and oxygen consumption (VO 2 ) of 250 ml/min. This individual is consuming 23% of the oxygen that is being delivered which is normal. CO = 5.0 l/min SaO 2 = 98% Hgb = 15 g/dl SvO 2 = 75% Oxygen Consumption VO 2 = CO x Hgb x 13.8 (SaO 2 - SvO ) 2 5 x 15 x 13.8 x ( ) = 238 ml O 2 /min Oxygen Delivery DaO = CO x Hgb x 13.8 x SaO x 15 x 13.8 x.98 = 1014ml O2/min O 2 Extraction VO 2 / DaO 2 = % of O2 extracted 238 / 1014 = 23%

96 96 The Essentials of Lesson: Oxygenation and Transport Hemodynamic Monitoring Topic: Oxygen Supply and Demand Practice Pearls Oxygen Demand Measuring oxygen consumption in the critically ill patient may be difficult unless the patient is on a ventilator. In this case a metabolic assessment" cart is used. In clinical practice, we can use indirect methods to assess the amount of oxygen that is extracted at the cellular level. We assume that oxygen extracted is actually consumed. Therefore, we often use the terms interchangeably. Determinants of Oxygen Supply The formula for arterial oxygen content (CaO 2) is: Oxyhemoglobin = Hgb x 1.38 x SaO 2 PLUS Dissolved Oxygen = PaO 2 x Hgb = hemoglobin 1.38 = 1 gram of hemoglobin when fully saturated carries 1.38 mls of oxygen SaO 2 = arterial oxygen saturation PaO 2 = partial pressure of oxygen in the arterial blood = conversion factor for measuring the dissolved oxygen

97 97 Oxygen Delivery It is important to remember the formula for cardiac output as well as the determinants of stroke volume. CO Cardiac Output CO HR x SV CaOa Arterial Oxygen Content CaO (Hgb x 1.38 x SaO ) + (PaO x ) 2 2 2

98 98 The Essentials of Lesson: Oxygenation and Transport Hemodynamic Monitoring Topic: Types of Catheters (SvO2, ScvO 2) Normal SvO Range 2 We always monitor trends rather than a single value. When monitoring SvO 2, we want to notice an upward or downward trend, as well as what the change in SvO 2 is in response to patient interventions. Insertion Guidelines If you do not have time to perform the in vitro calibration prior to insertion, you can perform a calibration once the catheter is inserted. The catheter will still provide necessary information to care for the patient. The optical signal may be impaired if the tip of the catheter is against the wall of the vein or artery, or if a small piece of fibrin covers the tip of the catheter. Kinking of the catheter can interrupt the light emission as well.

99 99 The Essentials of Hemodynamic Monitoring Lesson: Oxygenation and Transport Topic: Causes of DO2/VO 2 Imbalance Causes of Increased or Decreased SvO 2 If you note an abrupt increase in the SvO 2 value without any warning, check the pulmonary artery waveform to determine if the catheter has spontaneously wedged. If the value abruptly increased 10-20%, and nothing has changed with the patient, this is an early warning sign of a wedged catheter. Immediately follow your hospital protocol to withdraw the catheter slightly.

100 100 The Essentials of Lesson: Oxygenation and Transport Hemodynamic Monitoring Topic: Clinical Applications Practice Exercise If it is greater than 30%, the metabolic demands of the tissues are not being met indicating the tissues are trying to maximize oxygen extraction. On the other hand, if the O 2 ER is less than 22%, the metabolic demands are being met or the patient is unable to extract oxygen as in the case of severe sepsis.

101 Lesson 7 Pharmacological Management Of Hemodynamics Included in this Lesson: Managing Preload Managing Afterload Managing Contractility

102 102 Lesson Objectives Module: Hemodynamic Monitoring Lesson: Pharmocological Management of Hemodynamics Upon completion of this lesson you will be able to: Discuss the pharmacological management of hemodynamics - Identify the indications, contraindications, side effects and administration guidelines of interventions used to effect preload - Identify the indications, contraindications, side effects and administration guidelines of interventions used to effect afterload - Identify the indications, contraindications, side effects and administration guidelines of interventions used to effect contractility

103 Page of Lesson Take-away - Pharmaceutical Management of Hemodynamics Topic One: Managing Preload Introduction In this lesson we discuss the pharmacological management of hemodynamics and explore the different drugs that can increase or decrease preload, afterload, and contractility, thereby improving cardiac output and improving the body s ability to perfuse vital organs. Preload The force that stretches ventricles during diastole The amount of blood that fills ventricles during diastole Is measured on the right side by RAP/CVP and on the left by the PAOP. Increasing Preload Low PAOP (PAOP <8 mmhg) may be due to: Dehydration Excessive diuresis Third-spacing Bleeding Preload increased by increasing circulating blood volume. Done by administering crystalloid or colloid Crystalloids Crystalloids commonly used to enhance preload: Normal saline (NS) Lactated ringers (LR) Hypotonic solutions (D5W, 0.45 NS) are not for use in rapid fluid resuscitation. Possible contraindications of LR Possible complications of normal saline in large volumes Monitor electrolytes closely in patients receiving aggressive fluid resuscitation. Colloids Expand Intravascular Volume Colloids also used to increase preload and expand intravascular volume Colloid infusions Colloids should be used with caution when patient has altered capillary permeability (cardiopulmonary bypass patients and patients with septic shock.) Dextran and Hetastarch may be counterproductive in hypovolemic patients. Guidelines for use of blood products 2008 American Association of Critical-Care Nurses (AACN). All rights reserved.

104 Page of Fluid Challenge to Assess and Guide Therapy Assessing the response of the PAOP to a fluid challenge can help guide therapy. Administer fluid rapidly (over 10 to 15 minutes) in predetermined increments ( ml) and monitor the change in PAOP. Patient s individual ventricular compliance curve determines the magnitude of the change in PAOP. Implication of: Large (>7 mmhg) increase in PAOP Moderate increases in PAOP No increase in PAOP What to do when fluid ineffective Pulmonary Dysfunction A fluid challenge in patients with severe pulmonary dysfunction often results in increased CO and left ventricular stroke work index without a significant increase in PAOP Indicates that further fluid administration may be beneficial. A PAOP of mmhg generally indicates adequate preload and warrants consideration for an afterload reduction with a vasodilator (for purposes of improving SVI and CI.) Preload Reducers Diuretics (Furosemide) Nitroglycerin Morphine sulfate Milrinone (a phosphodiesterase inhibitor, Type III) Nitroprusside (Nipride) Classification for Estimating Short-term Mortality A classification for estimating short-term mortality in patients with acute myocardial infarction was developed to help provide guidance in medical and nursing decisions about therapy and in providing patient/family support. The underlying pathophysiology of subsets II, III, and IV: Increasing severity of left ventricular failure 4 Clinical subsets: Subset I: CI and PAOP within normal range (PAOP <18 mmhg and CI >2.2 L/min/m2) Subset II: CI is maintained >2.2 L/min/m2 but PAOP >18 mmhg Subset III: Classic hypovolemia; PAOP <18 mmhg and CI <2.2 L/min/m2 Subset IV: Cardiogenic shock 2008 American Association of Critical-Care Nurses (AACN). All rights reserved.

105 Page of Topic Two: Managing Afterload Introduction Here we explore techniques for managing afterload. Afterload The resistance ventricle must overcome to eject blood in the forward direction. Two determinants of afterload: Volume and mass of blood ejected from ventricle Compliance of vascular space into which the blood is ejected. Right ventricular afterload measured by PVR; left ventricular afterload measured by SVR. Pulmonary hypertension reflects in an elevated PVR. Cardiac diseases that may cause elevated PVR. Pulmonary diseases that may cause an elevated PVR. Reducing PVR Developing an effective therapy for pulmonary hypertension is difficult since pulmonary vasculature reacts less to neural and pharmacologic stimulation than systemic vasculature does. Ways to manage pulmonary hypertension (lower PVR): First ensure adequate oxygenation If PVR not improving and patient shows signs of right-sided failure, a more aggressive therapy is warranted. SVR Indications High SVR (>1200 dynes/sec/cm5) may reflect physiologic stress or left ventricular failure Medications that decrease SVR: nitroprusside, hydralazine, captopril, and to a lesser extent nitroglycerin Low SVR (<800 dynes/sec/cm5) may reflect septic shock or excessive administration of afterload reduction medications. Medications that increase SVR: dopamine, epinephrine, norepinephrine, phenylephrine, and vasopressin High PAOP and Low CO In patients with high PAOP and low cardiac output, vasodilators such as nitroprusside can improve ventricular function and reduce abnormally high SVR. In patients with a failing heart, either dobutamine or dopamine and nitroprusside can improve cardiac output The rationale for combining dopamine/dobutamine and nitroprusside 2008 American Association of Critical-Care Nurses (AACN). All rights reserved.

106 Page of Increasing SVR Drugs most commonly used to increase SVR: Dopamine Norepinephrine Epinephrine Phenylephrine Vasopressin Topic Three: Managing Contractility Introduction Here we look at the different factors influencing contractility and explore methods for managing contractility. Contractility The ability to shorten and develop tension within the myocardial cells Not possible to directly measure; instead use these indirect measures of contractility: SVI RVSWI LVSWI Patients with poor contractility may also have decreased CI, elevated filling pressures (RAP and PAOP,) and a low SvO 2. Blood pressure not a reliable indicator of low contractility. Conditions generally present with low contractility: Myocardial ischemia or infarction Congestive heart failure Cardiomyopathy Early stages of septic shock Increasing the Strength of Cardiac Contractions Inotropic Agents Dobutamine (Dobutrex) Dopamine Milrinone (Primacor) Negative Inotropic Effect Seen with hypoxia, acidosis, and hypercapnia so it is important to monitor patient for these conditions and correct promptly. A negative inotropic action can be produced by drugs. Closely monitor for hemodynamic stability patients taking these drugs: Beta blockers Calcium channel inhibitors Class I Antidysrhythmics Barbiturates 2008 American Association of Critical-Care Nurses (AACN). All rights reserved.

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108 108 Medication Calculation Pocket Card Lesson: Pharmacological Management of Hemodynamics Topic: Managing Preload IV Drip Rate: gtts/min = Volume to be infused (ml) x drip factor of tubing Time (min) to be infused Drug Concentration: Amount of drug in solution (g, mg, mcg) Amount of solution (ml) Information required to calculate IV infusion rates to deliver specific medication doses: 1. Dose to be infused (e.g. mcg/kg/min, mg/min, mg/h) 2. Concentration of solution (Ex: Dopamine 400 mg/250 D5W = 1.6 mg/ml) 3. Patient s weight in kilograms

109 109 Calculation of mcg/kg/min: Examples: dopamine, dobutamine, nitroprusside To calculate dose with infusion already in progress: mcg/ml x ml/h 60min/h kg = mcg/kg/min concentration pump setting pt weight dosage To calculate pump setting in ml/h if a given dose is ordered: mcg/kg/min x kg x 60 min/h mcg/ml = ml/h dosage pt weight concentration pump setting Example: Answer: Calculate the intravenous infusion rate in ml/h for a 70-kg patient requiring dobutamine, 5 mcg/kg /min, using a dobutamine drip of 500 mg in 25 ml D W. 5 Dosage to be administered: Dobutamine concentration: Patient weight: 5 mcg/kg/min 500 mg/250 ml = 2 mcg/ml or 2000 mcg/ml 70 kg Calculation: 5 mg/kg/min x 70 kg x 60 min/h 2000 mcg/ml = 10.5 ml/h Setting infusion pump at 10 ml/h will deliver approximately 5 mcg/kg/min of dobutamine.

110 Calculation of mcg/min: Examples: Nitroglycerine, norepinephrine, isoproterenol, epinephrine To calculate dose with infusion in progress: mcg/ml x ml/h 60 min/h = mcg/min concentration pump setting dosage To calculate pump setting in ml/h if a given dose is ordered: mcg/min x 60 min/h mcg/ml = ml/h dosage concentration pump setting Example: Answer: Calculate the IV infusion rate in ml/hour for a 70-kg patient requiring nitroglycerine, 50 mcg/min, using a nitroglycerine admixture of 50 mg in 250 ml D 5 W. Dosage to be administered: 50 mcg/min Nitroglycerine concentration: 50mg/250mL = 0.2 mg/ml or 200 mcg/ml Calculation: 50mcg/min x 60 min/h 200 mcg/ml = 15 ml/h Setting the infusion pump at 15mL/h results in the delivery of nitroglycerine at a dose of 50 mcg/min