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Core EM - Emergency Medicine Podcast

Core EM - Emergency Medicine Podcast

By: Core EM
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Episodes
  • Episode 222: Local Anesthetic Systemic Toxicity (LAST)

    Episode 222: Local Anesthetic Systemic Toxicity (LAST)
    Apr 7 2026
    We discuss this ominous complication of providing local anesthesia. Hosts: Elaine Jonas, MD Brian Gilberti, MD https://media.blubrry.com/coreem/content.blubrry.com/coreem/LAST.mp3 Download Leave a Comment Tags: Critical Care, Toxicology Show Notes I. Pathophysiology & Mechanisms Definition: Systemic toxicity secondary to local anesthetic (LA) via accidental intravascular injection or excessive systemic absorption. Threshold: Occurs when plasma concentration exceeds the safety threshold for cardiac and neural tissue. Agent Profile: Bupivacaine (High Risk) Highly lipophilic with high protein binding. “Fast-on, Slow-off” Kinetics: Strong Na+ channel binding with extremely slow dissociation during diastole. Myocardial Depression: Direct inhibition of Ca2+ release from the sarcoplasmic reticulum, impairing contractility. Low CC:CNS Ratio: The dose required for cardiac collapse is very close to the dose that triggers seizures (narrow safety margin). Contributing Factors: Acidosis/Hypercapnia: Increases the fraction of free drug and promotes ion trapping in the brain/heart; shifts the LA-binding curve toward higher toxicity. Hypoxemia: Exacerbates myocardial depression and lowers seizure threshold. II. Risk Assessment & Prevention Patient-Specific Risk Factors Extremes of Age: Neonates (low α-1-acid glycoprotein) and elderly (reduced clearance). Body Composition: Low muscle mass/frailty (decreased volume of distribution). Organ Dysfunction: Hepatic: Reduced metabolism of amide LAs. Renal: Accumulation of metabolites; risk of metabolic acidosis lowering seizure threshold. Cardiac: Reduced cardiac output slows hepatic delivery/clearance; heart failure patients are more sensitive to Na+ channel blockade. Pregnancy: Increased sensitivity to cardiotoxicity. Procedural Risk Factors Vascularity of Site (Highest to Lowest Risk): Intercostal blocks (highest absorption rate). Caudal/Epidural. Interfascial plane blocks (e.g., TAP block). Psoas compartment/Sciatic. Brachial plexus. Technique: Large volume infiltration, lack of ultrasound, lack of incremental injection. Prevention Mandates Weight-Based Dosing: Lidocaine (Plain): Max 4.5 mg/kg. Lidocaine (with Epi): Max 7 mg/kg. Bupivacaine: Max 2.5–3 mg/kg. Incremental Injection: 3–5 mL aliquots with frequent aspiration. Intravascular Marker: Use Epinephrine (1:200,000) to detect accidental IV placement (HR increase >10 bpmor SBP increase >15 mmHg). III. Clinical Presentation Neurologic Phase (Early to Late) Subjective: Metallic taste, tinnitus, circumoral numbness/tingling. Objective: Visual disturbances, agitation, confusion, tremors. Critical: Generalized tonic-clonic seizures, rapid progression to CNS depression, coma, and apnea. Note: Early phases are often masked in patients receiving midazolam or propofol. Cardiovascular Phase Initial: Hypertension and tachycardia (if epi used) or transient stimulatory phase. Conduction Defects: PR prolongation, QRS widening (classic sign), bundle branch blocks. Dysrhythmias: Bradycardia (most common), VT/VF, PEA, asystole. Contractility: Profound, refractory hypotension and cardiogenic shock. IV. Immediate Management Algorithm Goal: Prevent hypoxia/acidosis and sequester the toxin. 1. Initial Actions Stop Injection: Immediately halt all LA administration. Call for Help: Specify “LAST Protocol” and “Intralipid Kit.” Airway Management: 100% O2​. Hyperventilate slightly if needed to counter respiratory acidosis. Low threshold for intubation (hypoxia/acidosis rapidly worsen LAST). 2. Seizure Control First-line: Benzodiazepines (e.g., Midazolam). Avoid: Propofol if hemodynamically unstable (exacerbates cardiac depression). Neuromuscular Blockers: May be needed for ventilation, but remember they do not stop CNS seizure activity. 3. Lipid Emulsion Therapy 20% Indications: Start at first sign of serious toxicity (airway compromise, seizures, or CV instability). Bolus: 1.5 mL/kg IV over 1 minute. Infusion: 0.25 mL/kg/min immediately following bolus. If Instability Persists: Repeat bolus (up to 2 times). Increase infusion to 0.5 mL/kg/min. Upper Limit: ≈12 mL/kg total dose. 4. Modified ACLS Epinephrine: Use low doses (<1 mcg/kg) to avoid worsening arrhythmias and interfering with lipid rescue. Antiarrhythmics: Amiodarone is preferred. CONTRAINDICATED: Lidocaine: (Class Ib antiarrhythmic—will worsen toxicity). Vasopressin: Associated with poor outcomes in animal LAST models. Calcium Channel Blockers / Beta Blockers: Exacerbate myocardial depression. Refractory Arrest: Early consultation for ECMO or Cardiopulmonary Bypass (CPB). V. Differential Diagnosis for the Peri-Procedural Patient High Spinal: Ascending sensory/motor block, profound sympathectomy (hypotension/bradycardia). Anaphylaxis: Urticaria, wheezing (rare with amides, more common with esters). Air/Gas Embolism: Sudden dyspnea, “mill-wheel”...
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  • Episode 221: High-Output Heart Failure

    Episode 221: High-Output Heart Failure
    Mar 24 2026
    We discuss the diagnosis and treatment of one of EM's paradoxes: High-Output Heart Failure. Hosts: Nicolas Gonzalez, MD Brian Gilberti, MD https://media.blubrry.com/coreem/content.blubrry.com/coreem/HOHF.mp3 Download Leave a Comment Tags: Cardiology Show Notes Core EM Modular CME Course Maximize your commute with the new Core EM Modular CME Course, featuring the most essential content distilled from our top-rated podcast episodes. This course offers 12 audio-based modules packed with pearls! Information and link below. Course Highlights: Credit: 12.5 AMA PRA Category 1 Credits™Curriculum: Comprehensive coverage of Core Emergency Medicine, with 12 modules spanning from Critical Care to Pediatrics.Cost: Free for NYU Learners$250 for Non-NYU Learners Click Here to Register and Begin Module 1 1. Core Definition & Hemodynamic Profile Clinical Paradox: Congestive symptoms (pulmonary edema, JVD, peripheral edema) in the setting of a hyperdynamic, supranormal cardiac function. Hemodynamic Criteria: Cardiac Index (CI): >4.0 L/min/m2. Cardiac Output (CO): >8 L/min. Systemic Vascular Resistance (SVR): Pathologically low (vasodilated or shunted state). The “Warm” Phenotype: Unlike standard HFrEF/HFpEF (often “Cold and Wet”), HOHF presents as “Warm and Wet” due to low SVR and bounding pulses. 2. Pathophysiology: The Hemodynamic Paradox Primary Insult: Decreased SVR (either via peripheral vasodilation or arteriovenous shunting). Effective Arterial Blood Volume: Paradoxically low despite high total CO. Neurohormonal Cascade: Activation of Renin-Angiotensin-Aldosterone System (RAAS). Increased Sympathetic Nervous System tone. Increased Antidiuretic Hormone (ADH) secretion. Resultant State: Avid renal salt and water retention leading to massive plasma volume expansion. Cardiac Response: Chronic volume overload → eccentric remodeling → chamber dilation → eventual secondary myocardial failure/dilated cardiomyopathy. 3. Differential Diagnosis: Etiological “Buckets” Category A: Increased Metabolic Demand (Systemic) Hyperthyroidism/Thyrotoxicosis: Direct T3 effects: increased chronotropy/inotropy. Indirect effects: metabolic byproduct accumulation causing peripheral vasodilation. Myeloproliferative Disorders: High cell turnover and increased oxygen consumption drive compensatory CO increase. Sepsis (Hyperdynamic Phase): Cytokine-mediated global vasodilation. Note: Often transient; may transition to sepsis-induced myocardial depression. Category B: Peripheral Vascular Effects (Shunting/Vasodilation) Arteriovenous Fistulas (AVF) / Malformations (AVM): Most Common Cause: Iatrogenic AVF for Hemodialysis (ESRD population). Bypasses high-resistance capillary beds, dumping arterial blood directly into venous circulation. Chronic Liver Disease (Cirrhosis): Formation of “spider angiomata” and internal AV shunts. Impaired clearance of endogenous vasodilators (e.g., Nitric Oxide). Thiamine Deficiency (Wet Beriberi): Accumulation of pyruvate/lactate → systemic vasodilation. Histopathology: Vacuolation, myofiber hypertrophy, and interstitial edema. Chronic Lung Disease: Hypoxia/Hypercapnia-driven systemic vasodilation. Concomitant pulmonary HTN (RV remodeling) but preserved/high LV output. Others: Paget’s disease of bone (extensive micro-shunting), Carcinoid syndrome, Mitochondrial diseases, Acromegaly, Erythroderma. 4. Special Focus: Hemodialysis Access-Induced HOHF Physiologic Phases of AVF Creation: Acute Phase: Immediate ↓ SVR. ↑ Stroke volume and Heart Rate (SNS-mediated). Endothelial shear stress → Nitric Oxide release → further arterial dilation. Subacute Phase (Days to 2 Weeks): RAAS-driven volume expansion. ↑ Right Atrial, Pulmonary Artery, and LV End-Diastolic Pressures (LVEDP). Natriuretic peptide surge (BNP/ANP) peaks around Day 10. Chronic Phase (Weeks to Months): Adaptive hypertrophy. Decompensation occurs when dilation exceeds contractility limits. 5. Point-of-Care Physical Exam & Maneuvers Nicoladoni-Branham Sign (Pathognomonic for Shunt-driven HOHF): Maneuver: Manually compress the AVF (or inflate cuff to >50 mmHg above SBP) for 30 seconds. Positive Result: Reflexive bradycardia or a transient rise in systemic BP. Significance: Confirms the shunt is a major contributor to the cardiac workload. Peripheral Pulse Assessment: Water Hammer Pulses: Rapid upstroke and collapse. Quincke’s Pulse: Visible capillary pulsations in the nail beds. Traube’s Sign: “Pistol-shot” sounds auscultated over the femoral arteries. Volume Status: Rales, S3 gallop, peripheral edema (standard HF signs). 6. Diagnostic Workup (Technical Targets) POCUS / Echocardiography: Left Ventricle: Hyperdynamic function; EF typically >60%. Left Atrium: Significant dilation (Left Atrial Volume Index >34 mL/m2; Case study noted 72 mL/m2). IVC: Plethoric with minimal respiratory variation. Doppler: High ...
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  • Episode 220: Post-ROSC Care

    Episode 220: Post-ROSC Care
    Mar 3 2026
    We explore how to refine and optimize care in the vital minutes following ROSC. Hosts: Jonathan Elmer, MD, MS Brian Gilberti, MD https://media.blubrry.com/coreem/content.blubrry.com/coreem/Post-ROSC_care.mp3 Download Leave a Comment Show Notes Core EM Modular CME Course Maximize your commute with the new Core EM Modular CME Course, featuring the most essential content distilled from our top-rated podcast episodes. This course offers 12 audio-based modules packed with pearls! Information and link below. Course Highlights: Credit: 12.5 AMA PRA Category 1 Credits™Curriculum: Comprehensive coverage of Core Emergency Medicine, with 12 modules spanning from Critical Care to Pediatrics.Cost: Free for NYU Learners$250 for Non-NYU Learners Click Here to Register and Begin Module 1 I. Phase 1: Stabilization (Minutes 0–10) The “Rearrest” Window & Pathophysiology High-Risk Period: Rearrest rates reach 30% within the first minutes post-ROSC. Shock Incidence: Two-thirds of patients develop profound hypotension/shock as initial resuscitative efforts subside. Catecholamine Washout: Super-physiologic “code-dose” epinephrine (1mg IV) typically wears off within ~3 minutes post-ROSC, leading to predictable hemodynamic collapse. Secondary Injuries: Evaluate for “CPR-induced trauma” (blunt thoracic trauma, rib fractures, pneumothorax, liver/splenic lacerations). Immediate Resuscitative Actions Vascular Access: Transition rapidly from IO to reliable IV access within 1–2 minutes. Prioritize Intraosseous (IO) placement within 5 minutes if IV attempts fail; intra-arrest data suggests no significant difference in early outcomes. Vasoactive “Bridge”: Maintain a “bolus-dose” pressor at the bedside for immediate push-dose titration. Options: Phenylephrine, dilute Epinephrine, or dilute Norepinephrine (titrated to effect rather than rigid dosing). Physician-Specific Task: Arterial Line: Goal: Placement within 5 minutes of ROSC. Preferred Site: Femoral (by landmarks/blind if necessary) for speed; should be a <2-minute procedure. Utility: Immediate detection of rearrest and beat-to-beat titration of vasopressors. II. Phase 2: Diagnostic Workup (Minutes 10–40) Etiology Epidemiology ACS Shift: Acute Coronary Syndrome (ACS) is the cause in only 6–10% of resuscitated survivors (lower than historical estimates). Common Etiologies:Respiratory: COPD, pneumonia, mucus plugging. Cardiac: Arrhythmia (cardiomyopathy/scar), RV failure (PE), or LV failure. Neurological: Intracranial hemorrhage (SAH/ICH), status epilepticus (4–5%). Metabolic: Dialysis-related disarray/hyperkalemia. Toxicology: Overdose accounts for ~10% of cases in urban centers. The “Broad Net” Strategy “Rainbow Labs”: Comprehensive panel including toxicology and serial biomarkers. Pan-Scan Protocol: Components: CT/CTA Head/Neck, Contrast CT Chest/Abdomen/Pelvis. Diagnostic Yield: 50% for clinically significant findings (causes or consequences of arrest). Contrast Risk: Negligible (1–2% increase in AKI risk) compared to the high diagnostic utility. Avoid Anchoring: Do not assume ischemic EKG changes are the cause; they are frequently a consequence of the global arrest-induced ischemia. III. Hemodynamic & Respiratory Targets Mean Arterial Pressure (MAP) Autoregulation Shift: In acute brain injury/post-arrest, the lower limit of cerebral autoregulation shifts right, often requiring MAPs of 110–120 mmHg for adequate perfusion.Clinical Target: Aim for MAP >80 mmHg. The BOX Trial Nuance: While the BOX trial showed no difference between MAP 63 vs. 77, its cohort (Denmark) had exceptionally high survival rates (70% back to work) and short response times, which may not generalize to North American populations with lower shockable rhythm incidence. Permissive Hypertension: If the patient is “self-driving” to higher pressures, do not aggressively lower them, as this may be a physiologic demand for cerebral blood flow. Ventilation and Oxygenation PaCO2 Management: Target: High-normal to slightly hypercarbic (45–55 mmHg). Rationale: Avoid accidental hyperventilation (PaCO2 <30), which can cut cerebral blood flow by 50%. PaO2 Management: Maintain normoxia; avoid extreme hyperoxia, though trial data (BOX trial) suggests small variances (70 vs 90 mmHg) are likely neutral. IV. Neurological Prognostication & Communication The “Stunned” Brain Anoxic Depolarization: Occurs within ~2 minutes of pulselessness as ATP-dependent ion pumps fail. Clinical Pitfall: Early neurological exams (absent pupils, no motor response) are unreliable in the first hours as they reflect global neuronal “stunning” rather than definitive permanent injury. Time Horizon: Meaningful recovery is measured in days/weeks, not minutes/hours. Family Engagement Presence: Bring family to the bedside immediately, including during procedures or continued resuscitation. Psychological Impact: Significantly reduces PTSD, anxiety, and depression in...
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