Lab A Overview. Oxygenation. Ventilation. Anatomy. Prep Yourself. Prep Your Team. Prep Your Patient. Prep Your Stuff.

Transcription

1 Lab A Overview Oxygenation Ventilation Anatomy Prep Yourself Prep Your Team Prep Your Patient Prep Your Stuff Sniffing Position Jaw Thrust Mask Seal OPA / NPA Bag-Mask Ventilation Review this video for an overview of cellular respiration: Pulse Oximetry Pulse Oximetry: Definition of pulse oximetry including normal ranges and critical levels.

2 Procedure for obtaining accurate readings and assessing the validity of the pulse oximetry data. Lesson Instructions: Answer the following questions on this A4L Worksheet without consulting any resources to test your prior knowledge: 1. What is a normal pulse oximetry reading? 2. How can you determine the accuracy of the pulse ox reading? 3. What are some things that can give a falsely high pulse ox reading? 4. What are some things that can give a falsely low pulse ox reading? 5. Is pulse oximetry a real-time measure of tissue hypoxia? Use these resources to help you fill in any gaps in your understanding as identified in the A4L Worksheet: Video lesson Summary of key points: PaO2 measures oxygen in the tissues and SpO2 approximates this closely (hypoxia) but requires a blood gas analysis (usually an arterial blood draw). SpO2 is measured via pulse oximeters that measure the differences in absorption of light in pulsating blood and determines the percentage of hemoglobin molecules that are saturated with O2 compared to the overall number of hemoglobin molecules passing the sensor. SpO2 erroneous readings: Motion artifact from seizures or shivering Carboxyhemoglobin---from CO exposure Methemoglobin---congenital or acquired via chemical exposure or medication use producing abnormal hemoglobin that does not release oxygen once it has bound---causes cyanosis and is treated with methylene blue (sodium nitrite is a cyanide antidote and can cause methemoglobinemia---sodium nitrite is also a meat preservative) Hypoperfusion / hypothermia Sickle cell crisis (vasoocclusion) Skin pigmentation s impact is inconclusive Nail polish: o Nail polish s impact is negligible according to 2007 and 2008 studies that refuted the findings of 10 years prior. Zoll s operator s guide cautions that nail polish may alter the readings but their instructions do not require removal. Black, purple and dark blue had the most impact but the error was within the 2% margin of error

3 specifications for the device. Acrylic nails or newer nail polishes have not been fully studied and may or may not alter the accuracy of the SpO2 reading. An informal study by our department showed minimal impact from various shades of nail polish and various types (including gel Shellac ) with at most a difference of 2 percentage points between polished and unpolished nails. Simply rotating the sensor away from the nail bed provides a reasonable reading and is a simple and fast alternative to nail polish removal. Ambient light s impact is inconclusive although many probes have light shields. Delayed response possibly in fingers and toes (60-90 seconds) In sepsis or septic shock, SpO2 overestimates SaO2 by 2-5 percentage points and overestimates it more when SaO2 <90 % (hypoxemia). 1. What is a normal pulse oximetry reading? 2. How can you determine the accuracy of the pulse ox reading? 3. What are some things that can give a falsely high pulse ox reading? 4. What are some things that can give a falsely low pulse ox reading? 5. Is pulse oximetry a real-time measure of tissue hypoxia? Suggested answers: 1. What is a normal pulse oximetry reading? AHA says >94% 2. How can you determine the accuracy of the pulse ox reading? Test on yourself, look for full bars on the strength indicator, match the pulse oximeter s heart rate count to a palpated pulse rate, look at the waveform for a regular pattern. 3. What are some things that can give a falsely high pulse ox reading? carbon monoxide, sepsis, methemoglobinemia 4. What are some things that can give a falsely low pulse ox reading? hypotension, hypothermia 5. Is pulse oximetry a real-time measure of tissue hypoxia? probably there is a second lag Ventilation Review this lesson from Khan Academy troduction/v/meet-the-lungs.

4 If you haven't seen Khan stuff before, its very cool but you may be fooled into thinking that it is "beneath you"---but hang with it and you will learn something. Then, check out this post "The Bag-Valve-Mask as a Murder Weapon". Capnography Basics: Capnography is used to measure ventilation and can be used to assess perfusion and metabolism as well. Normal capnography readings and waveforms and the waveform that indicates bronchospasm. Capnography readings during cardiac arrest and if ROSC occurs. Capnography as a means to determine ETT placement. Questions to consider: 1. What three key body processes impact expired CO2 as measured by capnography (end-tidal CO2 or EtCO2)? 2. Does capnography measure ventilation or oxygenation? 3. What is a normal capnography reading? 4. How can the capnography waveform be used to assess for bronchiolar obstruction? 5. How is the capnography waveform used in intubation for verification of ET tube placement? 6. Describe the expected capngraphy reading during cardiac arrest. 7. How is capnography used to signal ROSC? 8. If an ET tube is placed in the esophagus after a patient has recently consumed carbonated beverages, what can be observed by the capnography waveform? 9. What causes an elevated EtCO2 level? 10. What causes a decreased EtCO2 level? Use these resources to help you fill in any gaps in your understanding as identified in the A4L Worksheet: Video lesson Weblinks: Capnography for Paramedics Sharkfin waveform (must point this direction) indicative of bronchiolar obstruction Normal waveform :

5 Answer the following questions again on this A4L Worksheet without consulting any resources to determine what gaps, if any, exist in your understanding after completing the lesson: 1. What three key body processes impact expired CO2 as measured by capnography (end-tidal CO2 or EtCO2)? 2. Does capnography measure ventilation or oxygenation? 3. What is a normal capnography reading? 4. How can the capnography waveform be used to assess for bronchiolar obstruction? 5. How is the capnography waveform used in intubation for verification of ET tube placement? 6. Describe the expected capngraphy reading during cardiac arrest. 7. How is capnography used to signal ROSC? 8. If an ET tube is placed in the esophagus after a patient has recently consumed carbonated beverages, what can be observed by the capnography waveform? 9. What causes an elevated EtCO2 level? 10. What causes a decreased EtCO2 level? Suggested answers: 1. What three key body processes impact expired CO2 as measured by capnography (end-tidal CO2 or EtCO2)? ventilation, perfusion, metabolism cellular metabolism creates CO2 which is brought to the lungs (perfusion) and exhaled during ventilation 2. Does capnography measure ventilation or oxygenation? ventilation oxygenation is measure by pulse oximetry 3. What is a normal capnography reading? generally accepted answer is although technically a better answer is probably How can the capnography waveform be used to assess for bronchiolar obstruction? westbound shark fin waveform 5. How is the capnography waveform used in intubation for verification of ET tube placement? a waveform indicates tracheal placement 6. Describe the expected capngraphy reading during cardiac arrest. consistent / standard waveform whose amplitude is based on perfusion and metabolism low readings in the presence of good CPR and appropriate ventilation indicates low metabolism and may drive a decision to cease resuscitation efforts 7. How is capnography used to signal ROSC? a sudden increase in EtCO2 may indicate ROSC useful during the two-minutes of CPR 8. If an ET tube is placed in the esophagus after a patient has recently consumed carbonated beverages, what can be observed by the capnography waveform? a waveform will potentially appear but decrease to zero after several breaths (perhaps 5-7 breaths) 9. What causes an elevated EtCO2 level? increased metabolism (elevated body temp?), low ventilation 10. What causes a decreased EtCO2 level? inappropriately high ventilation rate or volume or both, low metabolism, poor perfusion

6 Airway Anataomy Identification of the key airway structures involved in ALS Airway Management including the epiglottis, vallecula, arytenoid notch, esophagus, thyroid and cricoid cartilages. Use these resources to help you: Go to and watch the video Fiberoptic Tour of the Airway" Plans A, B, C... Planning for airway management includes the development of several plans as options BEFORE difficulties are encountered in order to maximize patient safety. The Elaine Bromiley Case: Video of the case and a critique. Patient Positioning

7 This is a one-hour long presentation. Not only will you want to watch it in segments, you will probably want to watch it a couple of times. It is FULL of brilliant stuff. Keep in mind that Dr. Levitan is lecturing to students who want to be ER docs so listen carefully. We wouldn't ask you to spend an hour watching anything that wasn't absolutely worth it. Two Thumbs Down--- OPA / NPA: 1. In terms of level of consciousness per AVPU, which of the OPA and NPA can be used in patients with various patients? 2. Describe if and when you would use both an OPA and NPA(s) at the same time in a patient. 3. Describe (and demonstrate in lab) the sizing and insertion of both OPAs and NPAs. 4. If your OPA keeps coming out of the patient s mouth, what should you do? 5. Describe a common side effect of the NPA and your management strategy for that problem. 6. Describe a contraindication to the NPA. Suggested answers: 1. In terms of level of consciousness per AVPU, which of the OPA and NPA can be used in patients with various patients? OPA only in unresponsive, NPA in any 2. Describe if and when you would use both an OPA and NPA(s) at the same time in a patient. Whenever you need more than one adjunct to help you keep an open airway. An OPA and 2 NPA s can be used. Do not delay ventilations to insert all of these utilize the time between ventilations. 3. Describe (and demonstrate in lab) the sizing and insertion of both OPAs and NPAs. OPA corner of mouth to angle of jaw; inserted inverted degrees until into the mouth and then rotated into position to avoid trapping the tongue. NPA s are inserted on the right side so that the bevel is against the septum or, if the right side is blocked, on the left with the bevel against the septum if possible to limit trauma and then rotated into position. NPA s are inserted until the trumpet bell is seated against the nose and then withdrawn slightly if that causes gagging. 4. If your OPA keeps coming out of the patient s mouth, what should you do? Get a larger one.

8 5. Describe a common side effect of the NPA and your management strategy for that problem. Epistaxis leave the NPA in place for some pressure on the bleeding and because you needed an airway! 6. Describe a contraindication to the NPA. Unstable facial trauma around the nose risk of further damage or theoretical insertion into the cranium if a basal skull fracture is present. Oral Suctioning: Describe proper technique for the use of manual and mechanical suction devices. 1. How deep should you insert a rigid oral suction catheter? 2. How long is it said that you are allowed to suction at one time? 3. Describe the proper technique for use of a V-Vac manual suction device (demonstrate this in lab as well). 4. How do you adjust the suction pressure on mechanical and manual suction devices? (demonstrate in lab as well) 5. How and when do you use the V-Vac manual suction adapters? Adjust suction pressure using the white knob on the right on this mechanical suction device. Adjust suction pressure on the V-Vac using the lever on the hard plastic handle just below where the canister attaches near the hand grip. V-vac set showing yellow adapter that fits over the canister tip (red cap is removed for use). The adapter allows you to attach the small suction catheter shown at the bottom for suctioning fluids or to use the double male adapter shown on the right of the picture to adapt to standard soft suction catheters used for ET tube suctioning. 1. How deep should you insert a rigid oral suction catheter? 2. How long is it said that you are allowed to suction at one time? 3. Describe the proper technique for use of a V-Vac manual suction device (demonstrate this in lab as well). 4. How do you adjust the suction pressure on mechanical and manual suction devices? (demonstrate in lab as well) 5. How and when do you use the V-Vac manual suction adapters? Suggested answers: 1. How deep should you insert a rigid oral suction catheter? only as far as you can see 2. How long is it said that you are allowed to suction at one time? 15 seconds

9 3. Describe the proper technique for use of a V-Vac manual suction device (demonstrate this in lab as well). make sure the tip is in the fluid to be suctioned and then squeeze the handle and hold it in the squeezed position to allow the canister to fill 4. How do you adjust the suction pressure on mechanical and manual suction devices? (demonstrate in lab as well) mechanical suctions have a dial or pull knob while the V-Vac manual suction has a slide or lever mechanism 5. How and when do you use the V-Vac manual suction adapters? the canister s tip is good for both fluid and chunks whereas the adapter allows you to attach a flexible tip catheter for fluids or to attach a flexible suction catheter for either tubes or pharyngeal suctioning Video Lesson (about 23 minutes from EMCrit critical care video blog / vodcast site but you can skip the first 2 minutes or so) Pay particular attention to the BVM part---the LMA part is something that is discussed later in the course Dr. Strayer advocates OPA and NPA use including multiples---just make sure you don't delay ventilation. A good practice is to use the time during compressions to improve your airway management with additional OPA and NPA. Do listen carefully to Dr. Weingart's discussion of ventilation technique at about the 15 minute mark Dr. Weingart emphasizes the use of capnography and discusses pulse ox lag Here is a study on BVM technique with three bullet points in summary: Comparison of BVM Hand Position Techniques In a simulated model, both 2-handed mask-face sealing techniques resulted in higher ventilatory tidal volumes than 1-handed technique Tidal volumes from 2-handed and modified 2-handed techniques did not differ. Rescuers should perform bag-valve-mask ventilation with 2-handed techniques. Reference: Annals of Emergency Medicine [January 2014] Answer the following questions again on this A4L Worksheet without consulting any resources to determine what gaps, if any, exist in your understanding after completing the lesson: 1. Why does the jaw thrust work best for paramedic manual airway management? 2. Describe good BVM technique. 3. Whenever the BVM is being used in the patient without an advanced airway in place, what additional airway adjuncts are considered mandatory?

10 4. Describe (and demonstrate in lab) how to perform proper mask seal for BVM. Suggested answers: 1. Why does the jaw thrust work best for paramedic manual airway management? the airway manager can position at the head of the patient and use both hands to control the mandible 2. Describe good BVM technique. Smooth compression of the bag every 6 seconds with an advanced airway in place (or twice during the pause in compressions) using just enough volume to produce a NORMAL chest rise (not maximal chest rise) 3. Whenever the BVM is being used in the patient without an advanced airway in place, what additional airway adjuncts are considered mandatory? an OPA or NPA and preferably an oral and two nasals if that s what it takes to keep a good airway position 4. Describe (and demonstrate in lab) how to perform proper mask seal for BVM. Two-thumbs down on the mask with both hands controlling the mandible (thus controlling the tongue) coupled with smooth compression of the bag at a rate of 10 breaths per minute EVEN IN CRITICAL PATIENTS especially in critical patients!