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February 1, 2020
You asked, and we listened! In this episode of the APEX Live podcast, we're going to do a little Q&A. We'll give you practice questions, and then we'll break each one down step-by-step. It’s kind of like going back to the basics or back to square one. Whether you're studying for the NCE or the CPC Exam, this isn't an episode you'll want to miss. Download our FREE crisis management checklists at: https://www.apexlive.com/blog/episode-9
January 1, 2020
Happy New Year! To kick off 2020, we're going to dive into how to approach the patient with an anticipated difficult airway. We'll explore several common airway algorithms, and we'll also discuss the "topical thunder" technique to anesthetize the airway for awake intubation. Show notes available at: https://www.apexlive.com/blog/episode-8
December 15, 2019
Surprise! In this mid-month bonus episode of the APEX Live Anesthesia Podcast, we'll talk about our friend and foe nitrous oxide. You know…that anesthetic gas that is great and horrible all at the same time. We'll briefly review its pharmacologic properties and then consider the current thinking and controversies about its clinical use.
December 1, 2019
In this episode of the APEX Live Anesthesia Podcast, we talk about difficult airway identification and the exams we use to help us recognize an airway that may be challenging. We also take a deep dive into what the different airway algorithms say about strategies for management.
November 1, 2019
In this episode of the APEX Live Anesthesia Podcast, we discuss a critical event that we could likely manage at some point in our anesthesia practice. Anaphylaxis is a severe life threatening generalized or hypersensitivity reaction. We will discuss the incidence, triggering agents, mechanism of action, signs and symptoms, and management of this crisis.
October 1, 2019
In this episode of the APEX Live Anesthesia Podcast we talk about the effort that goes into identifying and preventing aspiration and the controversies that surround RSI and cricoid pressure. We take a look at past research and opinions that have shaped the way we manage the prevention of aspiration, and what current research and opinion tells us now.   What You’ll Learn What is the history of aspiration prophylaxis? What are risk factors for aspiration? What does current evidence and opinion say about the administration of prophylactic medication for aspiration? Should ventilation be performed during rapid sequence induction? Is cricoid pressure really effective?   Resources/information discussed in podcast Risk factors for Aspiration from Nagelhout – Nurse Anesthesia ·       Emergency surgery ·       Full stomach ·       Obstetrics ·       Gastrointestinal obstruction ·       Ascites ·       Diabetic gastroparesis ·       Gastroesophageal reflux disease (GERD) ·       Hiatal hernia ·       Peptic ulcer disease ·       Difficult airway management ·       High gastric pressures/lower esophageal sphincter tone ·       Impaired airway reflexes ·       Head injury ·       Depressed level of consciousness ·       Seizures ·       Obesity ·       Scleroderma ·       Trauma or stress ·       Nausea or vomiting ·       Opioids ·       Cricoid pressure ·       Cardiac arrest ·       Severe hypotension ·       Inadequate anesthesia  Recommended Resources Driver BE et al. Drug Order in Rapid Sequence Intubation. Acad Emerg Med. 2019 Mar 4. doi: 10.1111/acem.13723. https://www.ncbi.nlm.nih.gov/pubmed/30834639 Masashi O, et al. The effectiveness of rapid sequence intubation (RSI) versus non-RSI in emergency department: an analysis of multicenter prospective observational study. Int J Emerg Med. 2017; 10:1. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5267589/ Nagelhout JJ. AANA journal course. Update for nurse anesthetists. Aspiration prophylaxis: is it time for changes in our practice? AANA J. 2003 Aug;71(4):299-303. https://www.ncbi.nlm.nih.gov/pubmed/13677226 Algie CM et al. Effectiveness and risks of cricoid pressure during rapid sequence induction for endotracheal intubation (Review). Cochrane Database Syst Rev. 2015 Nov 18;(11):CD011656. https://www.ncbi.nlm.nih.gov/pubmed/26578526 Boet S. et al. Cricoid pressure provides incomplete esophageal occlusion associated with lateral deviation: a magnetic resonance imaging study. J Emerg Med. 2012; 42: 606-11. ncbi.nlm.nih.gov/pubmed/21669510 Ehrenfeld, JM, et al. Modified RSI and Intubation: A survey of United States Current Practice. Anesth Analg. 2012 Jul; 115(1): 95-101. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3270153/ Schlesinger, S, Blanchfield, D. Modified rapid sequence induction of anesthesia: A survey of current clinical practice. AANA J. 2001; 69(4): 291-298. https://www.aana.com/docs/default-source/aana-journal-web-documents-1/modified_rapidseq0801_p291-298.pdf?sfvrsn=897f48b1_6 Sajayan, A, et al. Current practice of rapid sequence induction of anaesthesia in the UK - a national survey. Br J Anaesth. 2016 Sept; suppl 1: 169-174. https://www.ncbi.nlm.nih.gov/pubmed/26917599 Zeidan, AM, et al. The effectiveness of cricoid pressure for occluding the esophageal entrance in anesthetized and paralyzed patients: An experimental and observational glidescope study. Anesth Analg2014; 118:580–6. https://www.ncbi.nlm.nih.gov/pubmed/24557105 Rice, MJ, et al. Cricoid pressure results in compression of the postcricoid hypopharynx: The esophageal position is irrelevant. Anesth Analg. 2009; 109: 1546-52. https://www.ncbi.nlm.nih.gov/pubmed/19843793 Kei J . et al. Using ultrasonography to assess the effectiveness of cricoid pressure on esophageal compression. J Emerg Med. 2017; 53: 236-40. https://www.ncbi.nlm.nih.gov/pubmed/28602458 Trethewy CE, et al. Ideal cricoid pressure is biomechanically impossible during laryngoscopy. Acad Emerg Med. 2018 Jan;25(1):94-98. https://www.ncbi.nlm.nih.gov/pubmed/28960597 Lee D, et al. A multicenter prospective cohort study of the accuracy of conventional landmark technique for cricoid localization using ultrasound scanning. 2018: Oct;73(10):1229-1234. https://www.ncbi.nlm.nih.gov/pubmed/30044502 Salem MR, et al. Which Is the Original and Which Is the Modified Rapid Sequence Induction and Intubation? Let History Be the Judge! Anesth Analg. 2013: an;116(1):264-5. https://www.ncbi.nlm.nih.gov/pubmed/23387067 Mendelson CL. The aspiration of stomach contents into the lungs during obstetric anesthesia. Am J Obstet Gynecol. 1946;52:191–205. https://www.ncbi.nlm.nih.gov/pubmed/20993766 Sellick BA. Cricoid pressure to control regurgitation of stomach contents during induction of Anesthesia. Lancet. 1961;2:404–6. https://www.ncbi.nlm.nih.gov/pubmed/13749923 Stept WJ, & Safar P. Rapid induction-intubation for prevention of gastric-content aspiration. Anesth & Analg. 1970 Jul-Aug;49(4):633-6. https://www.ncbi.nlm.nih.gov/pubmed/5534675 Roberts RB & Shirley MA. Reducing the risk of acid aspiration during cesarean section. Anesth & Analg. 1974 Nov-Dec;53(6):859-68. https://www.ncbi.nlm.nih.gov/pubmed/4473928 Salem MR, et al. Cricoid Pressure Controversies: Narrative Review. 2017 Apr;126(4):738-752. https://anesthesiology.pubs.asahq.org/article.aspx?articleid=2596248 Falyar CR, & Kantzavelos L. Clinical Application of Point-of-Care Ultrasound Gastric Examination in the Management of an ASA Class 3E Patient: A Case Report. AANA J. 2018 Oct; 86(5):379-82. https://www.aana.com/docs/default-source/aana-journal-web-documents-1/clinical-application-of-point-of-care-ultrasound-gastric-examination-in-the-management-of-an-asa-class-3e-patient-a-case-report.pdf?sfvrsn=7a0754b1_6 Schuller PJ et al. Response to bispectral index to neuromuscular block in awake volunteers. Brit J Anaesth. 2015 Jul;115 Suppl 1:i95-i103. https://www.ncbi.nlm.nih.gov/pubmed/26174308   About Our Hosts  Sass Elisha EdD, CRNA, FAAN Sass been an academic and clinical educator at Kaiser Permanente School of Anesthesia since 2000. Dr. Elisha believes in the concept of a learning community where knowledge and ideas are shared to augment everyone’s understanding. As a result, he has made it a priority to disseminate information by contributing to multiple publications including Nurse Anesthesia, Case Management in Nurse Anesthesia and Crises Management in Nurse Anesthesia. His participation in additional scholarly activities help to further serve nurse anesthetists; publications including original research, a past COA director, a speaker at local, state and national conferences, and a volunteer for high school children who are interested in a career in healthcare. “I seek a method where teachers teach less and learners learn more.” Johann Comenius   Jeremy Heiner EdD, CRNA Jeremy is a clinician and an educator. He incorporates his favorite quote by Teddy Roosevelt into his clinical and educational practice: “Nobody cares how much you know, until they know how much you care.” Since 2004, Dr. Heiner has been working as a certified registered nurse anesthetist. In 2008 he joined Kaiser Permanente School of Anesthesia as an academic and clinical educator.  His contribution to CRNA learning includes producing clinically based anesthesia and critical care films, authoring textbooks and journal articles, presenting various anesthesia concepts at local, state, & national meetings, and chairing a NBCRNA test committee. He has over 10 years in independent practice and 15 years in an ACT model.   About APEX Live APEX Anesthesia teamed up with Sass Elisha EdD, CRNA, FAAN and Jeremy Heiner Ed.D., CRNA to bring you APEX Live – An engaging conference experience for CRNAs by CRNAs. We’ll help you prepare for the CPC Assessment in a fun and clinically relevant way.   Attend an APEX Live Conference Learn more about APEX Live events at www.apexlive.com.   Comments or Suggestions? We’re here to help you improve your practice, and we want to make sure our content is relevant for you. Click here to share your comments and suggestions.   Legal Disclaimer APEX Anesthesia Review, LLC expressly disclaims any liability in connection with the use of any content in its podcasts, social media posts, and all other published content by any third party. Music by Eino Toivanen, kongano.com
September 1, 2019
Episode Summary In this episode of the APEX Live Anesthesia Podcast, we will discuss hypotension and the treatments you can consider when you experience refractory hypotension. We talk about different causes of refractory hypotension with a focus on vasoplegic syndrome, what causes vasoplegic syndrome, and specific treatments for vasoplegic syndrome. What You’ll Learn What is the difference between vasoplegic syndrome and refractory hypotension? What are causes of refractory hypotension? How do you treat refractory hypotension? How would you manage vasoplegic syndrome? Resources/information discussed in podcast Differential causes for severe refractory hypotension MECHANISM   CAUSES Vasodilatory ·       Septic shock ·       Anaphylactic shock ·       Neurogenic shock ·       Post reperfusion injury after liver transplantation Obstructive ·       Cardiac tamponade ·       Tension pneumothorax ·       Embolism (air, gas, thrombus, bone, cement, amniotic fluid) Cardiogenic ·       Dysrhythmias ·       Ischemia/infarction ·       Cardiomyopathy ·       Poor ejection fraction Hypovolemic ·       Hemorrhage ·       Diuretics ·       Severe vomiting Metabolic ·       Hypothyroidism ·       Acute adrenal crises ·       Acidosis ·       Electrolyte disturbance (hypocalcemia, hyponatremia) Pharmacology (partial list) ·       Excessive anesthetic medications (deep, drug error) ·       Beta and calcium channel blockers ·       Clonidine ·       Calcium channel blockers ·       Tricyclic antidepressants ·       Selective serotonin receptor inhibitors ·       ACE/ARBI inhibitors ·       Phosphodiesterase inhibitors ·       Protamine ·       Heparin ·       Amiodarone Mechanical ·       Increased intra-abdominal pressure ·       Surgical compression of vena cava ·       Cardiopulmonary bypass  How methylene blue interrupts vascular smooth muscle vasodilation and hypotension VASCULAR ENDOTHELIUM                            SMOOTH MUSCLE         L-arginine®iNOS®NO®®®®®®®®­sGC ®®­ cGMP ®®vasodilation®®hypotension                             Ý                         MB   sGC=soluble guanylate cyclase, cGMP=cyclic guanosine monophosphate, iNOS=inducible nitric oxide synthetase, NO=nitric oxide, MB=Methylene blue   Recommended Resources Arevalo VN, Bullerwell ML. Methylene Blue as an adjunct to Treat Vasoplegia in patients undergoing Cardiac Surgery Requiring Cardiopulmonary Bypass: A Literature Review. AANA J. 2018;86(6):455-463. https://www.aana.com/docs/default-source/aana-journal-web-documents-1/methylene-blue-as-an-adjunct-to-treat-vasoplegia-in-patients-undergoing-cardiac-surgery-requiring-cardiopulmonary-bypass-december-2018.pdf?sfvrsn=1c2b56b1_4 Habib MA, Elsherbeny AG, Almehizia RA. Methylene Blue for Vasoplegic Syndrome Postcardiac Surgery. Indian J Crit Care Med. 2018;22(3) 168-173. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5879859/ Hosseinian L, Weiner M, Levin M, Fischer G. Methylene Blue: Magic Bullet for Vasoplegia. Anesthesia and Analgesia. 2016;122(1):194-201. https://www.ncbi.nlm.nih.gov/pubmed/26678471 Levy, B, et al. Vasoplegia Treatments: The past, the present and the future. Critical Care. 2018;22(1):52. https://ccforum.biomedcentral.com/articles/10.1186/s13054-018-1967-3 Liu H, Yu L, Yang L, Green MS. Vasoplegic syndrome: An update on perioperative considerations. Journal of Clinical Anesthesia. 2017;40:63-71. https://www.ncbi.nlm.nih.gov/pubmed/28625450 Shear T, Greenberg S. Vasoplegic Syndrome and Renin Angiotensin System Antagonists. APSF Newsletter.2012.;27(1). https://www.apsf.org/article/vasoplegic-syndrome-and-renin-angiotensin-system-antagonists/ Williams MD, Russell JA. Terlipressin or Norepinephrine in Septic Shock: Do We Have the Answer? J Thorac Dis. 2019; 11(Suppl 9):S1270–S1273.  https://www.ncbi.nlm.nih.gov/pubmed/31245106 About Our Hosts Sass Elisha EdD, CRNA, FAAN Sass been an academic and clinical educator at Kaiser Permanente School of Anesthesia since 2000. Dr. Elisha believes in the concept of a learning community where knowledge and ideas are shared to augment everyone’s understanding. As a result, he has made it a priority to disseminate information by contributing to multiple publications including Nurse Anesthesia, Case Management in Nurse Anesthesia and Crises Management in Nurse Anesthesia. His participation in additional scholarly activities help to further serve nurse anesthetists; publications including original research, a past COA director, a speaker at local, state and national conferences, and a volunteer for high school children who are interested in a career in healthcare. “I seek a method where teachers teach less and learners learn more.” Johann Comenius Jeremy Heiner EdD, CRNA Jeremy is a clinician and an educator. He incorporates his favorite quote by Teddy Roosevelt into his clinical and educational practice: “Nobody cares how much you know, until they know how much you care.” Since 2004, Dr. Heiner has been working as a certified registered nurse anesthetist. In 2008 he joined Kaiser Permanente School of Anesthesia as an academic and clinical educator.  His contribution to CRNA learning includes producing clinically based anesthesia and critical care films, authoring textbooks and journal articles, presenting various anesthesia concepts at local, state, & national meetings, and chairing a NBCRNA test committee. He has over 10 years in independent practice and 15 years in an ACT model. About APEX Live APEX Anesthesia teamed up with Sass Elisha EdD, CRNA, FAAN and Jeremy Heiner Ed.D., CRNA to bring you APEX Live – An engaging conference experience for CRNAs by CRNAs. We’ll help you prepare for the CPC Assessment in a fun and clinically relevant way. Attend an APEX Live Conference Learn more about APEX Live events at www.apexlive.com.  Comments or Suggestions? We’re here to help you improve your practice, and we want to make sure our content is relevant for you. Click here to share your comments and suggestions. Legal Disclaimer APEX Anesthesia Review, LLC expressly disclaims any liability in connection with the use of any content in its podcasts, social media posts, and all other published content by any third party.   Music by Eino Toivanen, kongano.com
August 1, 2019
In this episode of the APEX Live Anesthesia Podcast, we will briefly review the function of the hypothalamic-pituitary-adrenal axis, talk about both glucocorticoids and mineralocorticoids, and discuss to supplement and why. We’ll discuss the serious crisis that can occur when insufficient amounts of these hormones are available. We’ll finish by discussing what the evidences says about important topics related to steroids such as the best dose for PONV prophylaxis, should they be given for pain management, and if steroid administration perioperatively affects site infections or cancer recurrence. What You’ll Learn Can you review that blasted HPA axis? What is the difference between glucocorticoids and mineralocorticoids, and which should I administer? What does it mean to have acute adrenal insufficiency? What is the best dose for PONV prophylaxis? Does a single dose of steroid perioperatively affect site infection or cancer recurrence?  Recommended Resources Bruder EA, Ball IM, Pickett W. 2015. Single induction dose of etomidate versus other induction agents for endotracheal intubation in critically ill patients. Cochrane Database Syst Rev. doi 10.1002/14651858. [https://www.ncbi.nlm.nih.gov/pubmed/25568981] Awad K, et al. Dexamethasone combined with other antiemetics versus single antiemetics for prevention of postoperative nausea and vomiting after laparoscopic cholecystectomy: An updated systematic review and meta-analysis. Int J Surg. 2016;28(4):152-163. [https://www.ncbi.nlm.nih.gov/pubmed/27793640] Zorilla-Vaca A. Dexamethasone injected perineurally is more effective than administration intravenously for peripheral nerve blocks: A meta-analysis of RCT’s. Clin J 2018;34(3):276-284. [https://www.ncbi.nlm.nih.gov/pubmed/28591086] Sherif AA. Dexamethasone as Adjuvant for Femoral Nerve Block following Knee Arthroplasty: A Randomized, controlled study. Acta Anaesthesiol Scand. 2016; 60(7):977-87. [https://www.ncbi.nlm.nih.gov/pubmed/27255560] De Oliveira GS. Dose ranging study of the effect of preoperative dexamethasone on postoperative quality of recovery and opioid consumption after gynecologic surgery. 2011;3, 362-371. [https://www.ncbi.nlm.nih.gov/pubmed/21669954] Purushothaman A, et al. A prospective randomized study on the impact of low-dose dexamethasone on perioperative blood glucose concentrations in diabetics and nondiabetics. Saudi J Anesth. 2018;12(2): 198–203. [https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5875205/] Assante J., et al. Infection Associated with Single-Dose Dexamethasone for Prevention of Postoperative Nausea and Vomiting: A Literature Review. AANA J. 2015;83(4):281-8. [https://www.ncbi.nlm.nih.gov/pubmed/26390747] Polderman JA. Adverse side effects of dexamethasone in surgical patients. Cochrane Database Syst Rev. 2019;11. Doi 10.1002/14651858. [https://www.ncbi.nlm.nih.gov/pubmed/30821852]  About Our Hosts  Sass Elisha EdD, CRNA, FAAN Sass been an academic and clinical educator at Kaiser Permanente School of Anesthesia since 2000. Dr. Elisha believes in the concept of a learning community where knowledge and ideas are shared to augment everyone’s understanding. As a result, he has made it a priority to disseminate information by contributing to multiple publications including Nurse Anesthesia, Case Management in Nurse Anesthesia and Crises Management in Nurse Anesthesia. His participation in additional scholarly activities help to further serve nurse anesthetists; publications including original research, a past COA director, a speaker at local, state and national conferences, and a volunteer for high school children who are interested in a career in healthcare. “I seek a method where teachers teach less and learners learn more.” Johann Comenius Jeremy Heiner EdD, CRNA Jeremy Heiner is a clinician and an educator. Dr. Heiner incorporates his favorite quote by Teddy Roosevelt into his clinical and educational practice: “Nobody cares how much you know, until they know how much you care.” Since 2004, Dr. Heiner has been working as a certified registered nurse anesthetist. In 2008 he joined Kaiser Permanente School of Anesthesia as an academic and clinical educator and faculty member.  Dr. Heiner has contributed to CRNA learning by producing clinically based anesthesia and critical care films, authoring textbooks and journal articles, presenting various anesthesia concepts at local, state, & national meetings, and chairing a NBCRNA test committee. He has over 10 years in independent practice and 15 years in an ACT model. About APEX Live APEX Anesthesia teamed up with Sass Elisha EdD, CRNA, FAAN and Jeremy Heiner Ed.D., CRNA to bring you APEX Live – An engaging conference experience for CRNAs by CRNAs. We’ll help you prepare for the CPC Assessment in a fun and clinically relevant way. Attend an APEX Live Conference Learn more about APEX Live events at www.apexlive.com. Comments or Suggestions? We’re here to help you improve your practice, and we want to make sure our content is relevant for you. Click here to share your comments and suggestions. Legal Disclaimer APEX Anesthesia Review, LLC expressly disclaims any liability in connection with the use of any content in its podcasts, social media posts, and all other published content by any third party.   Music by Eino Toivanen, kongano.com  
July 1, 2019
Pulse oximetry is one of our favorite vital signs, in addition to measuring the percentage of oxygen bound to hemoglobin it: Verifies the pulse with a mechanical heart rate. Can verify capture when using transcutaneous pacing. Measures peripheral perfusion.   Principles of Pulse Oximetry: Emits a near-infrared and a red electromagnetic light source that is detected by a photodiode. The application of the Beer-Lambert law in pulse oximetry explains the absorption of the two light frequencies (infrared and red) by hemoglobin. The Beer portion describes how the amount of light absorbed is proportional to the concentration of the light absorbing substance (i.e., hemoglobin concentration). The Lambert portion describes how the amount of light absorbed is proportional to the distance the light travels within the absorbing substance (i.e., vasodilation causing more hemoglobin molecules to be present and absorb light). Oxyhemoglobin absorbs infrared light better at 940 nm, while deoxyhemoglobin absorbs red light better at 660 nm. An adequate pulse is necessary for pulse oximeters to work because the amount of red and infrared light fluctuates with the cardiac cycle within arterial blood.   Advantages of pulse oximetry: Saturation number – provides a value for oxygenation that is easy to comprehend (1-100%) Auditory tone – lets you know (without looking at the number) when the oxygen is falling. Provides a photoplethysmograph (Pleth or PPG) waveform that indicates the “mechanical” heart rate. Presence of a pleth waveform during transvenous or transcutaneous pacing indicated effective pacing. What can you do if you do not have a reliable tracing? Assure correct probe placement, reposition the probe and eliminate ambient light. If there is still a poor tracing consider poor peripheral perfusion (hypovolemia, vasoconstriction, PVD) or even hypoxemia! Moller JT, et al. Randomized evaluation of pulse oximetry in 20,802 patients: I. Design, demography, pulse oximetry failure rate, and overall complication rate. Anesthesiology. 1993 Mar;78(3):436-44. The perfusion index is a numerical value that measures the strength of the pulsations read by the pulse ox (indicating the strength of peripheral perfusion). It’s more useful as a trend instead of a single number. Van Genderen ME, et al. Peripheral perfusion index as an early predictor for central hypovolemia in awake healthy volunteers. Anesth Analg. 2013 Feb;116(2):351-6. Optimal pulse oximetry monitoring requires a site with dense capillaries like the fingertips, toes, forehead, nose, or earlobe. There is work being done on newer generations of pulse oximetry. Future uses of this technology have the potential to evaluate for respiratory rates, detection of carboxyhemoglobin and methemoglobin values, pulsus paradoxus and fluid responsiveness.   Disadvantages of pulse oximetry: Reusable pulse ox probes are disgusting and we should use single use probes. Wilkins MC. Residual bacterial contamination on reusable pulse oximetry sensors. Respir Care. 1993 Nov;38(11):1155-60.  There is a several second lag-time between the real oxygen saturation and pulse oximeter reading. Poor peripheral perfusion (such as vasoconstriction, hypothermia, and hypotension) cause difficulty with pulse oximetry readings. Carboxyhemoglobin is read as if it were oxyhemoglobin, which gives a falsely elevated pulse ox reading for a victim suffering from carbon monoxide poisoning and hypoxemia.   What do you do with a patient that has nail polish? Turn the pulse ox sideways 90o so that the emitter and the detector on the side of the fingertip, find another site, or clean off the nail polish. Yamamoto LG, et al. Nail polish does not significantly affect pulse oximetry measurements in mildly hypoxic subjects. Respir Care. 2008 Nov;53(11):1470-4.    Causes and mechanisms of unreliable SpO2 readings Intermittent drop-outs or inability to read SpO2 Poor perfusion (hypovolemia, vasoconstriction, hypothermia, pump failure or ysrhythmias) Falsely normal or falsely elevated SpO2 Carbon monoxide poisoning, Sickle cell vasoocclusive crisis Falsely low SpO2 Venous pulsations, excessive movement, intravenous pigmented dyes, inherited forms of abnormal hemoglobin, fingernail polish (?), severe anemia Falsely low or high SpO2 Methemoglobinemia, sulfhemoglobinemia, poor probe positioning, sepsis or septic shock     Differential Diagnosis CASE: 54 year old female scheduled for a laparoscopic assisted vaginal hysterectomy for uterine cancer. Toward the end of the procedure the surgeons request a dose of methylene blue during cystoscopy to assess for ureter compliance. Patient has a history of hypothyroidism, sickle cell disease, CAD and PVD. Five minutes after the injection of the methylene blue the patient’s oxygen saturation decreases from 99% to 91%.  Utilizing pulse oximetry data only here are some potential differential diagnoses: False reduction in saturation caused by methylene blue Pulse oximeter is not secured to finger well (check finger) Accidental extubation of patient (check ETT placement and capnography) Mucus plug or obstruction of ETT (suction ETT) Heart failure or dysrhythmia resulting in hypotension (check BP, ECG, capnography) Sickle cell crisis (check ABG, BP, ECG) Poor peripheral perfusion (change probe from finger to forehead)     References: Cannesson M, et al. Relation between respiratory variations in pulse oximetry plethysmographic waveform amplitude and arterial pulse pressure in ventilated patients. Crit Care. 2005 Jul; 9:R562-R568 Chan ED, et al. Pulse oximetry: understanding its basic principles  facilitates appreciation of its limitations. Respir Med. 2013 Jun;107(6):789-99.  DeMeulenaere, Susan. "Pulse oximetry: uses and limitations." The Journal for Nurse Practitioners 3.5 (2007): 312-317.  Lima AP, Beelen P, Bakker J. Use of a peripheral perfusion index derived from  the pulse oximetry signal as a noninvasive indicator of perfusion. Crit Care Med. 2002 Jun;30(6):1210-3Mannheimer PD. The light-tissue interaction of pulse oximetry. Anesth Analg. 2007 Dec;105(6 Suppl):S10-7. Review.    Music by Eino Toivanen, kongano.com  
June 28, 2019
Practical Anesthesia knowledge and wisdom for CRNAs, presented by CRNAs
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