Episode 937: Pneumomediastinum
Emergency Medical Minute
Contributor: Megan Hurley MD Educational Pearls: What is the mediastinum? The thoracic cavity is separated into different compartments by membranes The lungs exist in their own pleural cavities, and the mediastinum is everything in between The mediastinum extends from the sternum to the thoracic vertebrae and includes the heart, the aorta, the trachea, the esophagus, the thymus, as well as many lymph nodes and nerves. What is a pneumomediastinum? Air in the mediastinum How can pneumomediastinum be categorized? Traumatic Ex. Stab wound to the trachea Ex. Boerhaave’s...
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Episode 936: Etomidate vs. Ketamine for Rapid Sequence Intubation
Emergency Medical Minute
Contributor: Ricky Dhaliwal MD Educational Pearls: Etomidate was previously the drug of choice for rapid sequence intubation (RSI) However, it carries a risk of adrenal insufficiency as an adverse effect through inhibition of mitochondrial 11-β-hydroxylase activity A recent meta-analysis analyzing etomidate as an induction agent showed the following: 11 randomized-controlled trials with 2704 patients Number needed to harm is 31; i.e. for every 31 patients that receive etomidate for induction, there is one death The probability of any mortality increase was 98.1% ...
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Episode 935: Pregnancy Extremis - TOLDD
Emergency Medical Minute
Contributor: Aaron Lessen MD Educational Pearls: Pregnant patients at high risk of cardiac arrest, in cardiac arrest, or in extremis require special care A useful mnemonic to recall the appropriate management of critically ill pregnant patients is TOLDD T: Tilt the patient to the left lateral decubitus position This position relieves pressure exerted from the uterus onto the inferior vena cava, which reduces cardiac preload If the patient is receiving CPR, an assistant should displace the uterus manually from the IVC towards the patient’s left side O: Administer high-flow...
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Episode 934: Subendocardial Ischemia
Emergency Medical Minute
Contributor: Travis Barlock MD Educational Pearls: What is the ST segment? The ST segment on an ECG represents the interval between the end of ventricular depolarization (QRS) and the beginning of ventricular repolarization (T-wave). It should appear isoelectric (flat) in a normal ECG. What if the ST segment is elevated? This is evidence that there is an injury that goes all the way through the muscular wall of the heart (transmural) This is very concerning for a heart attack (STEMI) but can be occasionally caused by other pathology, such as pericarditis What if the ST...
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Episode 933: Benign Convulsions with Gastroenteritis
Emergency Medical Minute
Contributor: Alec Coston MD Educational Pearls: Causes of seizures in a fairly well-appearing child with diarrhea: Electrolyte abnormalities: hypocalcemia, hyponatremia Also hyperkalemia which causes arrhythmias and syncope - can appear like seizures Hypoglycemia If the child has diarrhea and appears very sick, differential diagnosis may include: Hemolytic uremic syndrome (HUS): simultaneous occurrence of microangiopathic hemolytic anemia, thrombocytopenia, and acute kidney injury Typically caused by Shiga-like toxin producing Escherichia coli (also known as EHEC, or...
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Episode 932: Induction Agent Hypotension
Emergency Medical Minute
Contributor: Aaron Lessen MD Educational Pearls: Induction agent selection during rapid sequence intubation involves accounting for hemodynamic stability in the post-intubation setting Many emergency departments use ketamine or etomidate A recent study sought to explore the rates of post-induction hypotension of ketamine compared with propofol Single center retrospective cohort study of patients between 2018-2021 Ketamine and propofol were both significantly associated with post-induction hypotension Ketamine adjusted odds ratio = 4.50 Propofol adjusted odds ratio = 4.88 50%...
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Episode 931: Naloxone in Cardiac Arrest
Emergency Medical Minute
Contributor: Aaron Lessen MD Educational Pearls: Can opioids cause cardiac arrest? Opioids can cause respiratory suppression and the subsequent low oxygen levels can lead to arrhythmias and eventually cardiac arrest. In 2023, 17% of out-of-hospital cardiac arrests (OHCA) were attributable to opioids. Given that this is a rising cause of cardiac arrest, should we just treat all cardiac arrest with naloxone (Narcan)? Naloxone is correlated with an increased chance of return of spontaneous circulation (ROSC) Additionally, a wide variety of individuals can be exposed to opioids and...
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Episode 930: Holding Costs
Emergency Medical Minute
Contributor: Aaron Lessen MD Educational Pearls: A study evaluated the patient-care impact and financial costs of holding patients in the ED, a nationwide issue Prospective, observational study of acute stroke management Conducted at a large urban, comprehensive stroke center The study evaluated patients in multiple categories: admitted to med/surg admitted to med/surg but held in the ED admitted to the ICU Admitted to ICU but held in the ED Examined the amount of time nurses and providers spent with each patient This was analyzed in conjunction with the...
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Episode 929: Traumatic Aortic Injury
Emergency Medical Minute
Contributor: Aaron Lessen MD Educational Pearls: Aortic injury occurs in 1.5-2% of patients who sustain blunt thoracic trauma Majority are caused by automobile collisions or motorcycle accidents Due to sudden deceleration mechanism accidents Clinical manifestations Signs of hypovolemic shock including tachycardia and hypotension, though not always present Patients may have altered mental status Imaging Widened mediastinum on chest x-ray, though not highly sensitive CT is more sensitive and specific, and signs of thoracic injury include an intimal flap, aortic wall...
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Laboring Under Pressure Episode 4: Obstetric Emergency in South Africa with Dr. Meghan Hurley
Emergency Medical Minute
Laboring Under Pressure Episode 4: Obstetric Emergency in South Africa with Dr. Meghan Hurley Contributors: Meghan Hurley MD, Travis Barlock MD, Jeffrey Olson MS3 Show Pearls Map of South Africa Referenced South Africa Geography Lesson There is a big disparity between Cape Town and its neighbor Khayelitsha. Cape Town is the legislative capital and economic hub of South Africa, known for its infrastructure, tourist attractions, and developed urban areas. Khayelitsha Township is a large informal settlement on the outskirts of Cape Town, with limited infrastructure and services compared to...
info_outlineContributor: Aaron Lessen, MD
Educational Pearls:
How does an automated blood pressure cuff work?
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Automated blood pressure cuffs work differently than taking a manual blood pressure.
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While taking a manual blood pressure, one typically listens for Korotkoff sounds (turbulent flow) while slowly deflating the cuff.
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An automatic blood pressure cuff only senses the pressure in the cuff itself and specifically pays attention to oscillations in the pressure caused by when the pressure of the cuff is between the systolic (heart squeezing) and diastolic (heart relaxed) pressures.
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These oscillations are at a maximum when the pressure in the cuff matches the mean arterial pressure (MAP) and therefore the machines are most accurate at reporting the MAP.
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The machines then use the MAP and other information about the oscillations to estimate the systolic and diastolic pressures, which are less accurate.
What should you do if you need more accurate systolic and diastolic blood pressures?
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Take a manual blood pressure.
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Get an arterial-line (a-line), which provides continuous data for the blood pressure at the end of a catheter.
What happens if the cuff is too big or too small for the patient?
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If the cuff is too small it will overestimate the pressure.
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If the cuff is too large it will underestimate the pressure.
What should you do if the cuff cycles a bunch of times before reporting a blood pressure?
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It probably isn’t very accurate so consider another method.
Bonus fact!
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The MAP is not directly in the middle of the systolic and diastolic pressures but is weighted towards the diastolic pressure. The MAP can be calculated by adding two-thirds of the diastolic pressure to one third of the systolic pressure. For example if the BP is 120/90 the MAP is 100 mmHg.
References
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Benmira, A., Perez-Martin, A., Schuster, I., Aichoun, I., Coudray, S., Bereksi-Reguig, F., & Dauzat, M. (2016). From Korotkoff and Marey to automatic non-invasive oscillometric blood pressure measurement: does easiness come with reliability?. Expert review of medical devices, 13(2), 179–189. https://doi.org/10.1586/17434440.2016.1128821
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Liu, J., Li, Y., Li, J., Zheng, D., & Liu, C. (2022). Sources of automatic office blood pressure measurement error: a systematic review. Physiological measurement, 43(9), 10.1088/1361-6579/ac890e. https://doi.org/10.1088/1361-6579/ac890e
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Vilaplana J. M. (2006). Blood pressure measurement. Journal of renal care, 32(4), 210–213. https://doi.org/10.1111/j.1755-6686.2006.tb00025.x
Summarized by Jeffrey Olson, MS3 | Edited by Meg Joyce, MS1 & Jorge Chalit, OMS3
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