Episode 947: Hypercapnia
Emergency Medical Minute
Educational Pearls: Physiologic stimulation of ventilation occurs through changes in levels of: Arterial carbon dioxide (PaCO2) Arterial oxygen (PaO2) Hypercapnia is an elevated level of CO2 in the blood - this primarily drives ventilation Hypoxia is a decreased level of O2 in the body’s tissues - the backup drive for ventilation Patients at risk of hypercapnia should maintain an O2 saturation between 88-92% Normal O2 saturation is 95-100% In patients who chronically retain CO2, their main drive for ventilation becomes hypoxia An audit was performed of SpO2 observations...
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Episode 946: Time to Defibrillation
Emergency Medical Minute
Contributor: Aaron Lessen, MD Educational Pearls: Quick background info Cardiac arrest is when the heart stops pumping blood for any reason. This is different from a heart attack in which the heart is still working but the muscle itself is starting to die. One cause of cardiac arrest is when the electrical signals are very disrupted in the heart and start following chaotic patterns such as Ventricular tachycardia (VTach) and Ventricular fibrillation (VFib) One of the only ways to save a person whose heart is in VFib or VTach is to jolt the heart with electricity and terminate the...
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Episode 945: Ketorolac vs. Ibuprofen
Emergency Medical Minute
Contributor: Ricky Dhaliwal, MD Educational Pearls: Ketorolac and ibuprofen are NSAIDs with equivalent efficacy for pain in the emergency department Oral ibuprofen provides the same relief as intramuscular ketorolac IM ketorolac is associated with the adverse effect of a painful injection IM ketorolac is slightly faster in onset but not significant Studies have assessed the two medications in head-to-head randomized-controlled trials and found no significant difference in pain scores IM ketorolac takes longer to administer and has a higher cost Ketorolac dosing ...
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Episode 944: Colchicine Overdose
Emergency Medical Minute
Contributor: Aaron Lessen, MD Educational Pearls: Colchicine is most commonly used for the prevention and treatment of gout There is research investigating the anti-inflammatory and cardioprotective effects of colchicine This drug has a narrow therapeutic index: a small margin between effective dose and toxic dose Colchicine overdoses can be unintentional or intentional and are associated with poor outcomes Phase 1: 10 - 24 hours after ingestion Patient looks well but may have mild symptoms mimicking gastroenteritis Phase 2: 24 hours - 7 days after ingestion ...
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Episode 943: Portal Vein Thrombosis
Emergency Medical Minute
Contributor: Travis Barlock, MD Educational Pearls: What is Portal Vein Thrombosis? The formation of a blood clot within the portal vein, which carries blood from the gastrointestinal tract, pancreas, and spleen to the liver Not only can this cause problems downstream in the liver, but the backup of venous blood can cause ischemia in the bowels How does it present? Similar to acute mesenteric ischemia: Sudden onset of abdominal pain, nausea, vomiting, and fever How is it diagnosed? Abdominal CT or MRI with contrast What causes it? Cirrhosis Coagulopathy (Factor V Leiden...
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Episode 942: Acute Mountain Sickness and High Altitude Cerebral Edema
Emergency Medical Minute
Contributor: Jorge Chalit-Hernandez, OMS3 Educational Pearls: Acute mountain sickness (AMS) is the term given to what is otherwise colloquially known as altitude sickness High altitude cerebral edema (HACE) is a severe form of AMS marked by encephalopathic changes Symptoms begin at elevations as low as 6500 feet above sea level for people who ascend rapidly May develop more severe symptoms at higher altitudes The pathophysiology involves cerebral vasodilation Occurs in everyone ascending to high altitudes but is more pronounces in those that develop symptoms The reduced...
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Episode 941: Rehydration in Pediatric Gastroenteritis
Emergency Medical Minute
Contributor: Meghan Hurley, MD Educational Pearls: Gastroenteritis clinical diagnoses: Diarrhea with or without vomiting and fever Vomiting in the absence of diarrhea has a large list of differential diagnoses, so the combination of diarrhea and vomiting in a patient is helpful to indicate the gastroenteritis diagnosis Symptom timeline is usually 1-3 days, but can last up to 14 days – diarrhea persists the longest Treatment for mild to moderate dehydration: oral or IV rehydration Begin orally to avoid unnecessary IV in a pediatric patient Administer ODT Ondansetron...
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Episode 940: Laceration Repair Methods
Emergency Medical Minute
Contributor: Aaron Lessen, MD Educational Pearls: If a patient sustains a cut, the provider has several options on how to close the wound. If they choose to suture the wound closed, it involves needles both in the form of injecting numbing medication (lidocaine) as well as with the suture itself. Other techniques are “needleless,” like closing the wound with adhesive strips (Steri-Strips) or skin adhesive (Dermabond). But which method is best? A recent study looked to compare guardian-perceived cosmetic outcomes of pediatric lacerations repaired with absorbable sutures, Dermabond, and...
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Episode 939: Serotonin Syndrome
Emergency Medical Minute
Contributor: Jorge Chalit-Hernandez, OMS3 Educational Pearls: Serotonin syndrome occurs most commonly due to the combination of monoamine oxidase inhibition with concomitant serotonergic medications like SSRIs Examples of unexpected monoamine oxidase inhibitors Linezolid - a last-line antibiotic reserved for patients with true anaphylaxis to penicillins and cephalosporins Methylene blue - not mentioned in the podcast due to its uncommon usage for methemoglobinemia Other medications that can interact with SSRIs to cause serotonin syndrome Dextromethorphan - primarily an...
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Episode 938: AHA Policy on Management of Elevated Blood Pressure (BP) in the Acute Care Setting
Emergency Medical Minute
Contributor: Aaron Lessen, MD Educational Pearls: Many patients present to the ED with elevated BP Many are referred from outpatient surgery centers or present after an elevated measurement at home Persistent questions on the best way to treat these patients The AHA published a scientific statement on the management of elevated BP in the acute care setting Hypertensive emergencies: SBP/DBP >180/110–120 mm Hg with evidence of new or worsening target-organ damage Includes aortic dissection or subarachnoid hemorrhage Require aggressive treatment Asymptomatic...
info_outlineContributor: Jorge Chalit-Hernandez, OMS3
Educational Pearls:
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Serotonin syndrome occurs most commonly due to the combination of monoamine oxidase inhibition with concomitant serotonergic medications like SSRIs
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Examples of unexpected monoamine oxidase inhibitors
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Linezolid - a last-line antibiotic reserved for patients with true anaphylaxis to penicillins and cephalosporins
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Methylene blue - not mentioned in the podcast due to its uncommon usage for methemoglobinemia
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Other medications that can interact with SSRIs to cause serotonin syndrome
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Dextromethorphan - primarily an anti-tussive at sigma opioid receptors that also has serotonin reuptake inhibition
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Clinical presentation of serotonin syndrome
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Altered mental status
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Autonomic dysregulation leading to hypertension (most common), hypotension, and tachycardia
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Hyperthermia
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Neuromuscular hyperactivity - tremors, myoclonus, and hyperreflexia
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Hunter Criteria (high sensitivity and specificity for serotonin syndrome):
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Spontaneous clonus
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Inducible clonus + agitation or diaphoresis
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Ocular clonus + agitation or diaphoresis
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Tremor + hyperreflexia
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Hypertonia, temperature > 38º C, and ocular or inducible clonus
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Management of serotonin syndrome
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Primarily supportive - benzodiazepines can help treat hypertension, agitation, and hyperthermia. Patients often require repeated and higher dosing of benzodiazepines
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Avoid antipyretics to treat hyperthermia since the elevated temperature is due to sustained muscle contraction and not central temperature dysregulation
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In refractory patients, cyproheptadine (a 5HT2 antagonist) may be used as a second-line treatment
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Patients with temperatures > 41.1º C or 106º F require medically induced paralysis and intubation to control their temperature
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References
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Boyer EW, Shannon M. The serotonin syndrome [published correction appears in N Engl J Med. 2007 Jun 7;356(23):2437] [published correction appears in N Engl J Med. 2009 Oct 22;361(17):1714]. N Engl J Med. 2005;352(11):1112-1120. doi:10.1056/NEJMra041867
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Dunkley EJ, Isbister GK, Sibbritt D, Dawson AH, Whyte IM. The Hunter Serotonin Toxicity Criteria: simple and accurate diagnostic decision rules for serotonin toxicity. QJM. 2003;96(9):635-642. doi:10.1093/qjmed/hcg109
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Ramsay RR, Dunford C, Gillman PK. Methylene blue and serotonin toxicity: inhibition of monoamine oxidase A (MAO A) confirms a theoretical prediction. Br J Pharmacol. 2007;152(6):946-951. doi:10.1038/sj.bjp.0707430
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Schwartz AR, Pizon AF, Brooks DE. Dextromethorphan-induced serotonin syndrome. Clin Toxicol (Phila). 2008;46(8):771-773. doi:10.1080/15563650701668625
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Thomas CR, Rosenberg M, Blythe V, Meyer WJ 3rd. Serotonin syndrome and linezolid. J Am Acad Child Adolesc Psychiatry. 2004;43(7):790. doi:10.1097/01.chi.0000128830.13997.aa
Summarized & Edited by Jorge Chalit, OMS3