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Podcast 996: Melatonin

Emergency Medical Minute

Release Date: 03/02/2026

Podcast 1024: Caffeine Toxicity show art Podcast 1024: Caffeine Toxicity

Emergency Medical Minute

Contributor: Taylor Lynch, MD Educational Pearls: Excessive caffeine intake can be dangerous. For normal adults, the toxicity level starts at 1000mg, which is equivalent to about 10 cups of coffee or 5 celsius drinks.  For normal adults, lethal levels are about 5-10 grams, which is equivalent to about 50-100 cups of coffee. Most of these outcomes are not from drinking caffeine, but instead concentrated caffeine pills. For children, toxic levels are 15mg per kg of the child.    Within the last 10 years 20-40 deaths due to caffeine intake have been reported. This...

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Podcast 1023: Torsades de pointes show art Podcast 1023: Torsades de pointes

Emergency Medical Minute

Contributor: Aaron Lessen, MD Educational Pearls: Case review of a patient with recurrent episodes of syncope and shortness of breath, during which she is found to have intermittent runs of polymorphic ventricular tachycardia Torsades de pointes is polymorphic ventricular tachycardia occurring in the setting of a prolonged QT/QTc Risk of torsades increases substantially when QTc exceeds 500ms Causes: Common reversible causes include QT-prolonging medications, hypokalemia, hypomagnesemia, hypocalcemia, bradycardia, and structural heart disease Congenital causes of a prolonged QT...

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Podcast 1022: Emergent Dialysis show art Podcast 1022: Emergent Dialysis

Emergency Medical Minute

Contributor: Taylor Lynch, MD Educational Pearls: When a patient who missed dialysis presents to the emergency department, our clinical concern is who needs to be admitted to the hospital for emergent dialysis and who can wait for their next regularly scheduled session. Dialysis sessions typically occur on Monday, Wednesday, and Friday, or Tuesday, Thursday, and Saturday. Acronym for indications for emergent dialysis: AEIOU Acidosis Patients may have an underlying cause for acidosis such as sepsis or DKA. Treat the underlying cause, but if the acidosis is unable to be...

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Podcast 1021: Pulmonary Edema From Naloxone Administration show art Podcast 1021: Pulmonary Edema From Naloxone Administration

Emergency Medical Minute

Contributor: Travis Barlock, MD Educational Pearls: What is pulmonary edema?  Pulmonary edema is the accumulation of fluid initially in the interstitium of the lungs, that when severe enough can also accumulate in the alveolar air sacs. It develops when the rate of fluid filtration through the pulmonary vasculature out-paces the lymphatics ability to drain the fluid.  There are 2 theories for what causes pulmonary edema in the setting of naloxone administration: catecholamine surge vs negative pressure/barotrauma Catecholamine Surge : Naloxone administration precipitates an...

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Podcast 1020: Benign Paroxysmal Positional Vertigo (BPPV) show art Podcast 1020: Benign Paroxysmal Positional Vertigo (BPPV)

Emergency Medical Minute

Contributor: Alec Coston, MD Educational Pearls: Benign Paroxysmal Positional Vertigo (BPPV) Common inner ear condition that can cause dizziness Diagnosis of BPPV can help to avoid admissions and extra imaging Three categories: positional, horizontal, and anterior Positional is the most common  Dizziness is not a positive indicator, a torsional nystagmus must be induced Dix's hallpike maneuver is done to diagnose and an epley maneuver is then used for treatment  Horizontal  Usually determined to be the case if the vertigo seems positional and the dix...

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Podcast 1019: Trauma Blunt Cardiovascular Injuries (BCVI) show art Podcast 1019: Trauma Blunt Cardiovascular Injuries (BCVI)

Emergency Medical Minute

Contributor: Aaron Lessen, MD Educational Pearls:  Blunt cerebrovascular injury (BCVI) BCVI is a traumatic injury to the carotid or vertebral arteries Patients may initially have no neurologic symptoms In some cases, a thrombus can form at the site of the injury and later cause ischemic stroke, sometimes hours after the original trauma CT angiography (CTA) of the neck is a useful screening tool for BCVI HIstorically, CTA was reserved for patients with high-risk mechanisms or neurologic symptoms CTA screening has expanded as understanding of BCVIs and their prevention...

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Podcast 1018: Occult Ventricular Fibrillation on Echocardiography show art Podcast 1018: Occult Ventricular Fibrillation on Echocardiography

Emergency Medical Minute

Contributor: Aaron Lessen, MD Educational Pearls: Big question in cardiac arrest: is the rhythm shockable? Shockable: ventricular fibrillation (VF) and pulseless ventricular tachycardia Non-shockable: asystole and pulseless electrical activity (PEA) Rhythm classification is typically based on ECG, but echocardiography can directly visualize myocardial fibrillation Occult VF: a rhythm that appears non-shockable on ECG but demonstrates VF on echocardiography A 2025 multicenter prospective study looked at 811 patients with out-of-hospital cardiac arrest 5.3% had occult VF...

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Podcast 1017: CPR Hand Placement show art Podcast 1017: CPR Hand Placement

Emergency Medical Minute

Contributor: Taylor Lynch, MD Educational Pearls:  CPR is an important life-saving measure designed for anyone to perform. Chest compressions works by two mechanisms:  Cardiac pump: Direct squeezing of the heart Thoracic pump: Increasing intrathoracic pressure, causing increased blood flow Proper hand placement per current AHA guidelines:  Hands are placed in the center of the chest, on the lower half of the sternum A recent study challenged this approach, using TEE during chest compressions to visualize the cardiac structures being compressed. They found...

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Podcast 1016: Hypokalemia show art Podcast 1016: Hypokalemia

Emergency Medical Minute

Contributor: Meghan Hurley, MD Educational Pearls: What is hypokalemia? Hypokalemia is when the measured blood level of potassium falls below 3.5 mEq/L (normal 3.5 - 5.2 mEq/L).  Can generally be considered in mild (3.0 - 3.5 mEq/L); moderate (2.5 - 2.9 mEq/L); and severe (<2.5 mEq/L) categories with differing treatment goals based on levels.  Should be noted that blood levels of potassium can be low while total body potassium is normal due to intracellular shift by certain agents like β-2 agonists (e.g. Albuterol) or insulin. There is no appreciable loss of insulin despite...

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Podcast 1015: Calcium in Hyperkalemia show art Podcast 1015: Calcium in Hyperkalemia

Emergency Medical Minute

Contributor: Meghan Hurley, MD Educational Pearls: What is hyperkalemia? Hyperkalemia is when the measured blood level of potassium reaches above 5.2 - 5.5 mEq/L (normal 3.5 - 5.2 mEq/L).  What are common causes of hyperkalemia?  Chronic or acute kidney disease. Medications that impact the Renin-Angiotensin-Aldosterone-System (RAAS).  Hypoaldosteronism and primary adrenal insufficiency (Addison’s Disease). What are concerns of hyperkalemia? The biggest concern with hyperkalemia is the impact on the cardiac conduction system. At differing levels of...

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More Episodes

Contributor: Taylor Lynch MD
Educational Pearls:

  • Melatonin is an endogenous hormone released primarily by the pineal gland
    • Also released by extrapineal regions in the retina, the GI tract, and some immune cells
  • Peak secretion occurs at night and is suppressed during the day
    • Secretion and production decrease with age
    • Older patients experience the greatest improvement in sleep latency and sleep quality
  • Mechanism of action in the suprachiasmatic nucleus of the hypothalamus
    • MT1 receptor
      • Reduces normal firing
    • MT2 receptor
      • Shifts the circadian rhythm
  • FDA approved for insomnia
    • Decreases sleep latency by 7 minutes
    • Increases total sleep time by 8 minutes
  • FDA approved for circadian sleep-wake disorders
    • Jet lag
      • Most effective in west-to-east travel
      • Best if crossing at least 5 time zones
    • Shift work
      • A study examined ED physicians and nurses with rotating shifts
      • Modest increase in deep sleep percentage
      • No difference in cognition or reaction time the day after taking melatonin
      • Nurses on rotating night shifts experienced increased total sleep time by 20 minutes
  • Dosing
    • 0.5 - 3 mg is the most evidence-based dosing
    • Higher doses increase the risk of rebound grogginess but do not improve outcomes

References

  1. Ahmad SB, Ali A, Bilal M, et al. Melatonin and Health: Insights of Melatonin Action, Biological Functions, and Associated Disorders. Cell Mol Neurobiol. 2023;43(6):2437-2458. doi:10.1007/s10571-023-01324-w
  2. Herxheimer A, Petrie KJ. Melatonin for the prevention and treatment of jet lag. Cochrane Database Syst Rev. 2002;(2):CD001520. doi:10.1002/14651858.CD001520
  3. Morgenthaler TI, Lee-Chiong T, Alessi C, Friedman L, Aurora RN, Boehlecke B, Brown T, Chesson AL Jr, Kapur V, Maganti R, Owens J, Pancer J, Swick TJ, Zak R; Standards of Practice Committee of the American Academy of Sleep Medicine. Practice parameters for the clinical evaluation and treatment of circadian rhythm sleep disorders. An American Academy of Sleep Medicine report. Sleep. 2007 Nov;30(11):1445-59. doi: 10.1093/sleep/30.11.1445. Erratum in: Sleep. 2008 Jul 1;31(7):table of contents. PMID: 18041479; PMCID: PMC2082098.
  4. Thottakam BMVJ, Webster NR, Allen L, Columb MO, Galley HF. Melatonin Is a Feasible, Safe, and Acceptable Intervention in Doctors and Nurses Working Nightshifts: The MIDNIGHT Trial. Front Psychiatry. 2020;11:872. Published 2020 Aug 27. doi:10.3389/fpsyt.2020.00872

Summarized and edited by Jorge Chalit, OMS4

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