Student Notes Chapter 40: ALS Assist 1. Chapter 40. ALS Assist

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1 Student Notes Chapter 40: ALS Assist 1 Chapter 40 ALS Assist Unit Summary After students complete this chapter and the related course work, they will be able to maximize their skill sets in order to lend a greater hand when assisting ALS. Additionally, the student will demonstrate an understanding of intubation and IV equipment, as well as a fundamental knowledge of basic airway management. Knowledge Objectives 1. Discuss advanced airway techniques. (p 1463) 2. Describe the basic anatomy and physiology of the airway. (pp ) 3. Explain the principles of basic airway management. (p 1465) 4. Describe the equipment and techniques used in endotracheal intubation. (pp ) 5. Explain the purpose of performing the Sellick maneuver. (pp ) 6. Discuss the benefits and disadvantages of multilumen and single-lumen airways. (pp ) 7. Discuss placement of a gastric tube. (pp ) 8. Understand the uses for continuous positive airway pressure (CPAP). (pp ) 9. Be familiar with the equipment necessary to gain intravenous (IV) access. (pp ) 10. Understand the techniques, alternative IV sites, and complications associated with IV access. (pp ) 11. Describe age-specific considerations in the care of pediatric patients. (p 1490) 12. Describe age-specific considerations in the care of geriatric patients. (p 1490) 13. Understand the use and techniques of cardiac monitoring. (pp ) Skills Objectives 1. Demonstrate how to perform the Sellick maneuver. (pp , Skill Drill 40-1) 2. Demonstrate how to perform orotracheal intubation. (pp , Skill Drill 40-2) 3. Demonstrate the steps in assembling IV equipment. (p 1479) 4. Demonstrate how to spike the bag with an IV administration set. (pp , Skill Drill 40-3) 5. Demonstrate how to start an IV. (pp , Skill Drill 40-4) 6. Demonstrate appropriate lead placement for both 4-lead and 12-lead ECG monitoring. (pp ) Lecture

2 Student Notes Chapter 40: ALS Assist 2 I. Introduction A. You may need to be familiar with the skills normally practiced at the AEMT and paramedic certification levels. B. These include: 1. Advanced airway techniques 2. Intravenous (IV) therapy 3. Cardiac monitoring II. Advanced Airway Techniques A. Establishing and maintaining the patient s airway is the single most important manipulative EMT skill. 1. The airway must be secured immediately or the patient will die. 2. Most conscious patients with an intact gag reflex can maintain their own airway. a. In managing a conscious patient, you may need only to provide oxygen and monitor the patient closely for any changes. 3. Patients whose consciousness is altered may require an oropharyngeal or nasopharyngeal airway and suctioning. B. The purpose of advanced airway management is to provide better airway protection and improve ventilation by using a tube to create a direct channel to the trachea. III. Anatomy and Physiology of the Airway A. The respiratory system consists of all of the body structures used for breathing. 1. The upper airway includes the nose, mouth, throat (pharynx), and larynx (vocal cords). a. The larynx is typically considered to be the dividing line between the upper and lower airway. 2. The lower airway includes the trachea, bronchi, and lungs. B. The mechanical process of breathing occurs through the use of the diaphragm and intercostal muscles. 1. These muscles contract during the active phase of breathing (inhalation). 2. During the passive phase of breathing (exhalation), air flows out of the lungs. C. The respiratory system delivers oxygen to the body and removes carbon dioxide. 1. This process takes place on two levels: a. Alveolar-capillary exchange i. Air breathed in during inhalation travels through the airways to the alveoli. ii. Oxygen-poor blood is circulated through the capillaries around each alveolus. iii. Oxygen in the alveoli crosses over into the bloodstream, and carbon dioxide crosses over into the alveoli. b. Capillary-cellular exchange i. Occurs throughout the body s cells ii. Cells give up carbon dioxide into the capillaries, and capillaries give up oxygen to the cells. D. Each living cell in the body requires a regular supply of oxygen.

3 Student Notes Chapter 40: ALS Assist 3 1. Some cells, such as those in the heart, brain, and nervous system, need a constant supply to survive and will be damaged or die if the supply is interrupted. 2. Other cells in the body can tolerate short periods without oxygen and still survive. IV. Basic Airway Management A. Always assess the airway first in an injured or ill patient. 1. Advanced airway techniques are begun only after proper basic airway management has been completed. B. The first step in airway management is opening a patient s airway. 1. Use the head tilt chin lift maneuver in a patient with no suspected spinal injury. 2. If there is a possibility of spinal injury, use the jaw-thrust maneuver. C. Assess the airway and evaluate the need for suctioning to remove: 1. Foreign bodies 2. Liquid 3. Blood D. Determine if the patient needs an airway adjunct. 1. Two readily available adjuncts are oropharyngeal and nasopharyngeal airways. V. Endotracheal Intubation A. Endotracheal intubation is the insertion of a tube into the trachea to maintain the airway. 1. If done through the mouth, it is called orotracheal intubation. 2. If done through the nose, it is called nasotracheal intubation. 3. In either case, the tube passes directly through the larynx between the vocal cords and then into the trachea. 4. It is a very effective method for controlling a patient s airway and has many advantages over other airway management techniques. 5. Indicated for: a. Patients who cannot protect their own airway b. Patients who need prolonged artificial ventilation B. Equipment 1. Before an orotracheal intubation attempt begins, it is vitally important to assemble all the equipment that you will need. a. Laryngoscope handle and blade b. Properly sized endotracheal (ET) tube c. Stylet d. 10-mL syringe e. Water-soluble lubricant for the ET tube f. Suction unit with rigid and soft-tip catheters g. Magill forceps h. Stethoscope i. Commercial securing device

4 Student Notes Chapter 40: ALS Assist 4 j. Secondary confirmation device 2. Laryngoscope a. The purpose of the laryngoscope is to sweep the tongue out of the way and align the airway so that the vocal cords can be visualized and the ET tube passed through them. 3. ET tubes a. The size of an ET tube is specified by the measurement of the inside diameter of the tube. b. The proper-sized tube for adults ranges from 7.0 to 8.5 mm. c. For most efficient use, use the largest-diameter ET tube that will pass easily through the vocal cords. d. For children, it is best to have a chart or length-based resuscitation tape device to help you with sizing the ET tube. e. A standard 15/22-mm adapter attaches to any ventilation device. i. Make sure that the adapter is securely pushed into the tube so that it does not pull off as you ventilate the patient. f. Note the centimeter mark for placement of the ET tube by looking at where the tube lines up with the teeth on an intubated patient. i. In average-sized adults, the tube-to-teeth mark is usually at around 22 cm. 4. Stylet a. A plastic-coated wire called a stylet may be inserted into the ET tube to add rigidity and shape to the tube during the intubation. b. Bend the tip of the stylet to form a gentle curve for adult intubations. c. Do not insert the stylet past Murphy s eye because it could puncture or lacerate delicate airway tissues. d. Before intubation is attempted, always confirm that the stylet is not sticking out past the end of the ET tube. 5. Syringe a. Use a 10-mL syringe to test for air leaks in the ET tube before intubation and to fill the cuff when the tube is placed correctly in the trachea. 6. Other equipment a. A suction unit may be needed to clear secretions or blood so the vocal cords can be visualized. b. The use of a commercial securing device is an effective means of ensuring the tube does not move once it is in the correct position. C. The Sellick maneuver 1. The Sellick maneuver can be used to intubate a patient who has no cough and/or gag reflex. 2. Helps reduce the chance of regurgitation and aspiration of stomach contents, and move the vocal cords into better view during the intubation procedure 3. Follow the steps in Skill Drill When performing this maneuver, be sure to correctly identify anatomic landmarks to avoid damaging other structures and inadvertently obstructing the airway. D. The intubation procedure: visualized (oral) intubation 1. You may intubate only if authorized to do so by off-line or online medical control. 2. You must act quickly, carefully, and efficiently. 3. Be sure to use standard precautions, including the use of: a. Gloves b. Eye protection c. A mask 4. An intubation attempt should not take more than 30 seconds.

5 Student Notes Chapter 40: ALS Assist 5 a. The 30-second time limit begins when ventilation stops and the laryngoscope blade is inserted into the patient s mouth. b. It ends when ventilation has begun again. 5. If the attempt is not successful, stop, withdraw the tube, oxygenate the patient, and try again according to your local protocols. 6. Intubation is a multiple-person task, especially in a situation involving cardiac arrest and use of an automatic external defibrillator (AED). a. First EMT applies and uses the AED. b. Second and third EMTs perform CPR at a ratio of 30 compressions to 2 ventilations. c. Fourth EMT prepares and intubates the patient. 7. Follow the steps in Skill Drill 40-2 to perform visualized orotracheal intubation. 8. It is essential that you use a secondary method of confirming proper tube placement. a. Esophageal detector devices are designed to connect directly to the ET tube adapter end once the patient has been intubated. i. Two commonly used devices are a syringe with a plunger and a bulb syringe. ii. The devices work by attempting to withdraw air from the ET tube. b. End-tidal carbon dioxide detectors and capnography monitors sense the amount of carbon dioxide during the exhalation phase of ventilation. i. Place the device between the ET tube adapter and the bag-mask device and ventilate the patient normally. ii. After a minimum of six breaths, look for evidence of carbon dioxide production. c. Capnography monitors can also be used for secondary confirmation of ET tube placement. i. During ventilation, the amount of carbon dioxide present is displayed as a number or as a positive waveform on the monitor. d. These devices do not give a 100% guarantee that the tube is in the correct location. 9. Primary confirmation is: a. Direct visualization of the tube passing through the vocal cords b. Auscultating good bilateral breath sounds c. Seeing the patient s chest rise and fall with each ventilation 10. Never let go of the ET tube until it is secured. 11. Intubation complications a. Intubating the right main stem bronchus i. If the ET tube is placed into the trachea too far, it will pass into the right main stem bronchus. ii. Only the right lung will be ventilated. iii. Deflate the cuff and pull the ET tube back slightly. b. Intubating the esophagus i. If the ET tube is inserted without first seeing the vocal cords, it may easily be inserted into the esophagus. ii. The result is rapid inflation of the patient s stomach rather than ventilation of the lungs. iii. Auscultate over the epigastrium and over the left and right apices and bases of the lungs. c. Aggravating spinal injury i. Intubation must occur without moving the patient s neck from the neutral, in-line position. d. Increased hypoxia i. If the procedure cannot be completed within 30 seconds, stop and ventilate the patient with a bag-mask device and 100% oxygen for 2 to 3 minutes before trying again. e. Patient vomiting

6 Student Notes Chapter 40: ALS Assist 6 i. Always check for a gag reflex before intubation. ii. Always have a suction unit ready in case the patient vomits during the intubation procedure. f. Laryngospasm i. Trying to insert an ET tube through the vocal cords can cause the cords to spasm. ii. Stop the intubation attempt and ventilate the patient with a bag-mask device. g. Trauma i. The laryngoscope and the tip of the ET tube can injure the lips, teeth, tongue, gums, and other airway structures. ii. Careful attention to technique will minimize the risk of trauma. h. Mechanical failure i. You may hear or feel air coming from the oropharynx when ventilating the patient, indicating that the cuff may not have enough air in it. ii. Get more air into the cuff or replace the tube. i. Patient intolerant of the ET tube i. Before removal of the tube becomes necessary, ensure that a suction unit is nearby and ready. ii. Deflate the cuff and carefully withdraw the ET tube as the patient exhales. j. Decrease in heart rate i. Monitor the patient s vital signs carefully and continuously. ii. The heart rate may decrease when the airway is stimulated or if the tube is misplaced in the esophagus. iii. Reassess and confirm tube placement. VI. Multilumen Airways A. Multilumen airways are advanced airways that do not require visualization of the vocal cords for placement. 1. Examples include the Combitube and pharyngeotracheal lumen airway. 2. They are designed to provide lung ventilation when placed in the trachea or the esophagus, thus making them much easier to insert than an ET tube. 3. If the tube happens to go into the trachea, ventilation is provided directly into the lungs as with an ET tube. 4. If the tube goes into the esophagus, as occurs most often, ventilation can still be provided to the patient. B. Contraindications 1. Multilumen airways should not be used in the following patients: a. Conscious or semiconscious patients with a gag reflex b. Children younger than 14 years c. Adults shorter than 5 d. Patients who have ingested a caustic substance e. Patients who have a known esophageal disease C. Removing the multilumen airway 1. If the patient will no longer tolerate the airway, it should be removed. 2. Remember that the patient will likely vomit when the airway is removed, so a suction unit must be readily available. 3. When you are ready, simply deflate both balloon cuffs, and gently remove the tube.

7 Student Notes Chapter 40: ALS Assist 7 VII. Single Lumen Airways A. King LT airway 1. The King LT is a single lumen airway that is blindly inserted into the esophagus. 2. It consists of a curved tube with ventilation ports located between two inflatable cuffs. a. One cuff is designed to seal the esophagus, while the other is intended to seal the oropharynx. b. Openings located between these two cuffs provide ventilation of the lungs. 3. Contraindications a. Intended for airway management in patients who are taller than 4 b. High airway pressures may cause air to leak into the stomach or out of the mouth. c. If the trachea is intubated, the airway must be removed and another attempt made to place it in the esophagus. B. Laryngeal mask airway 1. The laryngeal mask airway (LMA) was originally developed for use in the operating room, but its use has expanded to the field. 2. Consists of two parts: the tube and the mask or cuff 3. After blind insertion, the device molds and seals itself around the laryngeal opening by inflation of the mask. 4. Comes in seven sizes and can be used in children and adults VIII. Gastric Tubes A. Sometimes a patient may require placement of a tube through the nose or mouth that extends into the stomach. 1. Example: cardiac arrest patient who already has an advanced airway 2. A nasal or oral gastric tube relieves gastric distention caused by the introduction of air into the stomach during positive-pressure ventilation prior to the advanced airway being placed. a. Gastric distention causes a significant risk of passive regurgitation and aspiration in unconscious patients, which can result in pneumonia. 3. The gastric tube may also be used by emergency department staff to lavage the stomach in cases of accidental or intentional overdose. B. After placement, the gastric tube is measured to determine the proper depth of insertion, lubricated, and then passed through the nostril or mouth and into the stomach. 1. Stomach contents and air can then be aspirated or passively allowed to escape through the tube. 2. Proper placement can be confirmed by: a. Aspiration of stomach contents with a syringe b. Listening with a stethoscope as air is introduced into the gastric tube with a syringe c. Radiograph on arrival at the emergency department IX. Continuous Positive Airway Pressure A. Continuous positive airway pressure (CPAP) is used in breathing patients who are alert and able to follow commands, who have reduced function of the alveoli due to: 1. Congestive heart failure

8 Student Notes Chapter 40: ALS Assist 8 2. Chronic obstructive pulmonary disease 3. Asthma B. A tight-fitting mask is placed over the mouth and nose and connected to an oxygen source capable of delivering flow rates of at least 50 L/min. 1. During the inspiratory phase of respiration, oxygen-rich air is supplied at flow rates high enough to increase airway pressure. 2. During the expiratory phase, the patient exhales against a resistance called positive end-expiratory pressure. 3. The combination of pressure results in an increased: a. Volume of air in the lungs b. Alveolar surface available for gas exchange c. Oxygen diffusion across the cell membrane C. CPAP may be helpful in patients with severe respiratory distress when initial treatments of highflow oxygen administration are not successful. 1. Make sure to monitor vital signs regularly. X. Intravenous Therapy A. Develop a routine to follow as you assemble the appropriate equipment. 1. This will help you keep track of your equipment and the steps necessary to complete successful IV administration. B. Indications 1. Many medications used by ALS crews are given by the IV route. 2. A fluid bolus may be indicated for patients who are dehydrated because of vomiting or excessive diarrhea, or patients who have experienced blood loss because of hemorrhage. C. Assembling the equipment 1. Gather and prepare all of your equipment before the attempt to start IV administration. 2. By anticipating the needs of your ALS partner, you can help make the IV equipment assembly possible. 3. Table 40-2 shows a logical sequence of steps for assembling your equipment. D. Choosing an IV solution 1. In the prehospital setting, the choice of IV solution is limited to: a. Isotonic crystalloids b. Normal saline c. Lactated Ringer s solution 2. D5W (5% dextrose in water) is often reserved for administering medication. 3. Each IV solution bag is wrapped in a protective sterile plastic bag and is guaranteed to remain sterile until the posted expiration date. a. Once the protective wrap is torn and removed, the IV solution has a shelf life of 24 hours. 4. The bottom of each IV bag has two ports: a. An injection port for medication b. An access port for connecting the administration set

9 Student Notes Chapter 40: ALS Assist 9 5. The more common prehospital volumes are 1,000 ml and 500 ml. E. Choosing an administration set 1. An administration set moves fluid from the IV bag into the patient s vascular system. 2. Each administration set has a piercing spike protected by a plastic cover. 3. There are different sizes of administration sets for different situations and patients. 4. Most drip sets have a number visible on the package, which indicates the number of drops it takes for a milliliter of fluid to pass through the orifice and into the drip chamber. a. Drip sets commonly used in the prehospital environment come in two primary sizes: microdrip and macrodrip. i. A microdrip set allows 60 gtt/ml through the small, needlelike orifice inside the drip chamber. ii. A macrodrip set allows 10 to 15 gtt/ml through a large opening between the piercing spike and the drip chamber. 5. Preparing an administration set a. Verify the solution and check for solution clarity. b. To spike the bag with the administration set, follow the steps in Skill Drill c. Saline locks (buff caps) are a way to maintain an active IV site without running fluids through the vein. i. Used primarily for patients who do not need additional fluids but may need rapid medication delivery ii. Attached to the end of an IV catheter and filled with a few milliliters of normal saline to keep blood from clotting F. Catheters 1. An IV catheter is a hollow, laser-sharpened needle inside a hollow plastic tube that is inserted into a vein. 2. Once the catheter is properly placed, the needle is removed, leaving the catheter in the vein. 3. Select the catheter size based on the: a. Need for the IV b. Condition of the patient s veins c. Location for the IV 4. Catheters are sized by their diameter and referred to by the gauge of the catheter. a. A larger-diameter catheter corresponds to a smaller gauge. G. Starting an IV 1. The first step in starting an IV is to apply a tourniquet proximal to the site where venipuncture is to be performed. 2. When a suitable vein is identified, the area should be cleaned according to local protocol to decrease the chance of introducing potentially infectious materials through the skin. 3. The needle/catheter is then introduced into the vein, the needle withdrawn and disposed of properly, and IV tubing or lock placed. 4. Use tape or a commercially available device to secure the catheter. 5. Always wear gloves during the procedure. 6. Skill Drill 40-4 covers how to start an IV. H. Securing the line 1. Tape the area so that the catheter and tubing are securely anchored in case of a sudden pull on the line. 2. Avoid circumferential taping around any extremity because it can act like a constricting band and stop circulation.

10 Student Notes Chapter 40: ALS Assist 10 I. Alternative IV sites and techniques 1. Intraosseous (IO) needles are used for emergency venous access as defined by protocol when other IV access is difficult or impossible. a. Often patients are experiencing a life-threatening situation such as cardiac arrest, status epilepticus, or progressive shock. b. The IO needles are generally inserted in the proximal tibia. 2. An external jugular IV provides venous access through the external jugular veins in the neck. a. The catheter is inserted midway between the angle of the jaw and the midclavicular line. b. These punctures can be difficult because these veins are surrounded by a very tough, fibrous sheath that may make access difficult. J. Possible complications of IV therapy 1. Local reactions include problems like infiltration and phlebitis. 2. Systemic complications include allergic reactions and circulatory overload. K. Local IV site reactions 1. Infiltration a. Infiltration is the escape of fluid into the surrounding tissue when the IV catheter is not in the vein. b. This escape of fluid can cause a localized area of edema or swelling. c. Some of the more common reasons are: i. The IV catheter has passed completely through the vein and out the other side. ii. The IV catheter tip moves out of the vein because of patient movement or the tape securing the line coming loose. iii. The catheter was inserted at too shallow an angle and has only entered the tissue surrounding the vein. iv. Fluid is escaping from the vein because of prior venipuncture. d. Signs and symptoms include: i. Edema or swelling at the catheter site ii. Extremely slow IV flow iii. Patient complaint of tightness and pain around the IV site e. To correct the infiltration, stop the flow, remove the IV catheter, and reinsert it at an alternative site. 2. Phlebitis a. Phlebitis is inflammation of the vein. b. Not usually seen in emergency prehospital patients c. Often associated with fever, tenderness, and red streaking along the course of the associated vein d. Common causes include: i. Localized irritation and infection from nonsterile equipment ii. Prolonged IV therapy iii. Irritating IV solutions 3. Occlusion a. In IV therapy, occlusion is the physical blockage of a vein or catheter. b. Common causes include: i. Formation of a clot due to blood in the catheter or insufficient flow rate ii. Proximity to a valve iii. Resting on the IV line or crossing the arms iv. High blood pressure causing blood to back up into the line 4. Vein irritation

11 Student Notes Chapter 40: ALS Assist 11 a. More common with IV medication administration and very uncommon with administration of pure IV fluids b. Patients often complain immediately that the IV is bothering them. i. It may tingle, sting, or itch. 5. Hematoma a. A hematoma is an accumulation of blood in the tissues surrounding an IV site. b. Hematomas result from vein perforation or catheter removal. c. If a hematoma develops when IV catheter insertion is attempted, the procedure should stop. i. Direct pressure should be applied to help minimize bleeding. ii. Application of ice may help. d. If a hematoma develops after a successful catheter insertion, evaluate the IV flow and the hematoma. L. Systemic complications 1. A systemic complication can evolve from reactions or complications associated with IV insertion. a. Systemic complications usually involve other body systems and can be life threatening. 2. Allergic reactions a. True anaphylaxis is possible and must be treated aggressively. b. Allergic reactions can be related to a person s unexpected sensitivity to an IV fluid or medication. c. Common signs and symptoms include: i. Itching ii. Edema of face and hands iii. Bronchospasm iv. Wheezing v. Shortness of breath vi. Hives d. If an allergic reaction occurs, discontinue the IV fluid and remove the solution, maintain the airway, and monitor ABCs and vital signs. 3. Air embolus a. Healthy adults can tolerate as much as 200 ml of air introduced into the circulatory system. b. Patients who are already ill or injured can be adversely affected if any air is introduced. c. Properly flushing an IV line will help eliminate any potential of introducing air into a patient. i. IV bags are designed to collapse as they empty to help prevent this problem. ii. Be sure to replace empty IV bags with full ones. d. Treat a patient by placing him or her on the left side with the head down. 4. Circulatory overload a. An unmonitored IV bag can lead to circulatory overload. b. Problems occur when the patient has cardiac, pulmonary, or renal dysfunction. i. These types of conditions do not allow the patient to tolerate the additional demands associated with increased circulatory volume. c. The most common cause in the prehospital setting is failure to readjust the drip rate after flushing an IV line immediately after insertion. d. Patient presentation includes: i. Shortness of breath ii. Jugular vein distention iii. Increased blood pressure iv. Crackles v. Acute peripheral edema

12 Student Notes Chapter 40: ALS Assist 12 e. To treat a patient with circulatory overload: i. Slow the IV rate to keep the vein open. ii. Raise the patient s head to ease respiratory distress. iii. Administer high-flow oxygen. iv. Monitor vital signs and shortness of breath. 5. Vasovagal reactions a. Some patients have anxiety concerning needles or in response to the sight of blood. b. Patients can present with: i. Anxiety ii. Diaphoresis iii. Nausea iv. Syncopal episodes c. Treatment centers on providing supportive care. i. Lower the head of the stretcher. ii. Administer oxygen if indicated. iii. Monitor vital signs. 6. Catheter shear a. Although uncommon, catheter shear is a potential complication when starting an IV that could have a devastating effect on your patient. b. May occur if you attempt to reinsert the needle through the catheter after the needle has been partially withdrawn M. Troubleshooting 1. Several factors can influence the IV flow rate. 2. It is always helpful to perform the following checks after completing IV administration. a. Check your administration set. b. Check the height of the IV bag. c. Check the type of catheter used. d. Check the tourniquet. N. Age-specific considerations 1. Pediatric and geriatric populations warrant specific attention. 2. IV therapy for pediatric patients a. Physically, a child has smaller veins. i. A small-gauge catheter should be used so that the vessel will be traumatized as little as possible. ii. A 22-gauge to 24-gauge is appropriate. b. Volume control is important. i. Using a special type of microdrip set called a Volutrol allows you to fill the large drip chamber with a specific amount of fluid and administer only this amount. 3. IV therapy for geriatric patients a. Smaller catheters may be preferable unless rapid fluid replacement is needed. b. The use of tape can lead to skin damage, so be careful when taping IV catheters and tubing. c. Be careful when using macrodrips because they can allow rapid infusion of fluids, which may lead to fluid overload. XI. Cardiac Monitoring

13 Student Notes Chapter 40: ALS Assist 13 A. 12-lead ECG can help in the early identification of an acute myocardial infarction (AMI). 1. The interpretation of cardiac rhythm may not be an EMT skill, but it is helpful to be able to place electrodes and leads on a patient in preparation for cardiac monitoring. B. Electrical conduction system of the heart 1. The heart contains a network of specialized tissue, called the electrical conduction system, that is capable of conducting electrical current throughout the heart. 2. The flow of electrical current through this network causes contractions of the heart that produce pumping of blood. 3. The process of electrical conduction a. The main function of the electrical conduction system is to create an electrical impulse and transmit it through the heart in an organized manner. b. The electrical conduction system contains these components: i. The sinoatrial (SA) node, the heart s main pacemaker, which paces at a rate of 60 to 100 beats/min. ii. Three intermodal pathways that transmit the pacing impulse from the SA node to the atrioventricular (AV) node iii. The AV node, which transmits the impulse from the atria to the ventricles iv. The bundle of His v. The right and left bundle branches C. Electrodes and waves 1. The ECG electrodes pick up the electrical activity of the heart, and the ECG machine converts it to waves. 2. The way an ECG tracing looks depends on where the lead is placed. D. The ECG complex 1. One complex represents one beat in the heart. 2. The complex consists of several waves: the P, QRS, and T waves. 3. A segment is a specific portion of the complex. 4. An interval is the distance, measured in time, occurring between two cardiac events. a. The time between the beginning of the P wave and the beginning of the QRS complex is known as the P-R interval. E. ECG paper 1. The paper on which an ECG is recorded contains a grid. a. Each little box represents 1/25 of a second, or 0.04 second. b. Each bigger box is composed of five smaller boxes, or 0.20 second. c. Five big boxes equal 1 second. F. Normal sinus rhythm 1. Sinus rhythm is a rhythm in which the SA node acts as the pacemaker. a. All of the P waves should be the same. b. A normal heart rate for most people is 60 to 100 beats/min. c. A rhythm strip with these attributes is showing normal sinus rhythm. G. The formation of the ECG 1. Production of the heart s rhythm is a continuous process, with no actual period of rest or inactivity. 2. The process is as follows:

14 Student Notes Chapter 40: ALS Assist 14 a. The baseline is a period when the majority of the cardiac muscle is at rest. b. The SA node produces an electrical impulse that is conducted through the internodal pathways and into the atrial cardiac muscle cells, resulting in atrial depolarization. c. The impulse passes through the AV node. d. The impulse travels through the bundle of His, right and left bundles, the fascicles, and the Purkinje system. e. As the ventricular muscle cells repolarize, the T wave is formed. 3. If the heart is functioning normally, this process will repeat over and over continuously. H. Arrhythmias 1. An arrhythmia is an abnormal rhythm of the heart. 2. Sinus bradycardia a. Bradycardia refers to a slow heart rate, usually less than 60 beats/min. b. Therefore, sinus bradycardia is a rhythm that has consistent P waves, consistent P-R intervals, and a regular heart rate less than 60 beats/min. c. Sinus bradycardia typically becomes a problem when the heart rate drops to less than 50 beats/min. 3. Sinus tachycardia a. Tachycardia refers to a fast heart rate, usually more than 100 beats/min. b. Sinus tachycardia is a rhythm that has consistent P waves, consistent P-R intervals, and a regular heart rate more than 100 beats/min. c. Tachycardia may cause a decrease in cardiac output when the rate becomes so high that the stroke volume is affected. d. A heart rate of 160 to 220 beats/min can pose clinical and diagnostic challenges. 4. Ventricular tachycardia a. A basic definition of ventricular tachycardia is simply the presence of three or more abnormal ventricular complexes in a row with a rate of more than 100 beats/min. b. In general, it is a very regular rhythm. 5. Ventricular fibrillation a. Ventricular fibrillation is a rapid, completely disorganized ventricular rhythm with chaotic characteristics. i. Undulations of varying shapes and sizes ii. No specific pattern iii. No discernable P, QRS, or T waves b. There is no organized beating of the heart. c. The best chance for patient survival is dependent on rapid defibrillation. 6. Asystole a. Asystole refers to the complete absence of any electrical cardiac activity. b. It looks like a straight or almost straight line on an ECG strip. c. The patient is clinically dead at this point. I. Assisting with cardiac monitoring 1. You may have a 4-lead ECG or a 12-lead ECG system. 2. New cardiac monitors include several new features using modern technology. 3. They are compact, light, and portable and combine defibrillation and monitoring capabilities. J. Lead placement 1. A 4-lead ECG uses four leads, which are electrodes attached to wires that are attached to the cardiac monitor. a. These four leads are called the limb leads because they are placed on the patient s limbs, or close to them.

15 Student Notes Chapter 40: ALS Assist 15 i. White lead on the right shoulder or arm ii. Black lead on the left shoulder or arm iii. Green lead on the right low abdomen or leg iv. Red lead on the left low abdomen or leg b. It does not matter where the leads are placed on the limbs, as long as all four are at least 10 cm from the heart. 2. When using a 12-lead ECG, electrodes are placed as in a 4-lead placement as well as in very specific locations on the patient s chest. a. Position the V 1 and V 2 leads on each side of the sternum at the fourth intercostal space. b. V 4 is placed at the fifth intercostal space in the midclavicular line. c. V 3 is placed between V 2 and V 4. d. V 5 is placed in the anterior axillary line, and V 6 in the midaxillary line at the fifth intercostal space. 3. It is very important to have direct skin contact when obtaining an ECG. a. If the skin is sweaty or oily, wipe and clean the skin thoroughly with a towel. b. If the patient s hair prevents attachment of the leads, use a razor to remove excess hair. 4. The importance of obtaining a 12-lead ECG is for early identification of potential myocardial ischemia. 5. Advantages of 12-lead monitoring: a. Early identification of acute ischemia b. Accurate identification of arrhythmias K. ST-segment elevation myocardial infarction (STEMI) 1. A STEMI is a specific type of myocardial infarction in which the ST segment of the cardiac cycle is elevated. 2. A STEMI is treatable by techniques that rapidly restore perfusion to the coronary arteries. 3. Many cardiac monitors available are capable of reading a 12-lead ECG and indicating whether the patient may be having a STEMI. a. In the goal of achieving the shortest time to reperfusion, potential delays can be minimized. b. Time is muscle. 4. Working as a team, regardless of certification level, to provide optimal care to your patient is essential. XII. Summary A. There may be cases in which an EMT may find it necessary to be familiar with skills normally practiced at the AEMT and paramedic level. These skills include advanced airway techniques, IV therapy, and cardiac monitoring. B. An advanced airway technique is endotracheal intubation, the insertion of a tube into the trachea to maintain the airway. C. Additional advanced airway care devices include the Combitube, pharyngeotracheal lumen airway, the King LT, and the laryngeal mask airway. D. IV therapy is used to replace fluids in a patient with shock or to administer medications. E. Cardiac monitoring with an ECG is an advanced skill that the EMT may provide in assistance to the AEMT or paramedic.

16 Student Notes Chapter 40: ALS Assist 16 Post-Lecture Unit Assessment Keyed for Instructors 1. What is the first step in managing an airway? 2. What is the usual tube-to-teeth length when intubating? 3. How long should an intubation attempt take? 4. What does a gastric tube do? 5. What does the term spike mean in the context of IV administration? 6. Which catheter would have a larger diameter, a 14 or 18 gauge? 7. A catheter placed completely through a vein creates local edema and pain and has a very slow flow rate. What is the most likely cause of this problem? 8. A patient who experiences a vasovagal reaction to the sight of a needle or blood might present with what signs and symptoms? 9. An embolism caused by a solid piece of plastic from a catheter is known as. 10. What is the rhythm called when all P waves are consistent, the P-R interval is consistent, and the rate is between 60 and 100 beats/min?

17 Student Notes Chapter 40: ALS Assist 17 Knowledge Objectives

18 Student Notes Chapter 40: ALS Assist 18 Knowledge Objectives