A 58-year-old man is brought to the emergency department after an apparent suicide attempt. He was found lethargic by his wife, who also discovered a suicide note. The patient has a history of coronary artery disease and hypertension. His temperature is 37.7 C (100 F), blood pressure is 76/40 mm Hg, pulse is 40/min, and respirations are 12/min. Examination shows diffuse bilateral wheezing. Extremities are cold and clammy. ECG shows profound sinus bradycardia with first-degree atrioventricular block. The patient is given intravenous fluids and atropine; however, his bradycardia and hypotension do not improve. In addition to ensuring adequate oxygenation, which of the following is the most appropriate next step in management?

Question

A 58-year-old man is brought to the emergency department after an apparent suicide attempt.  He was found lethargic by his wife, who also discovered a suicide note.  The patient has a history of coronary artery disease and hypertension.  His temperature is 37.7 C (100 F), blood pressure is 76/40 mm Hg, pulse is 40/min, and respirations are 12/min.  Examination shows diffuse bilateral wheezing.  Extremities are cold and clammy.  ECG shows profound sinus bradycardia with first-degree atrioventricular block.  The patient is given intravenous fluids and atropine; however, his bradycardia and hypotension do not improve.  In addition to ensuring adequate oxygenation, which of the following is the most appropriate next step in management?

Quizplus · Accepted Answer

This patient's presentation - bradycardia, atrioventricular block, hypotension, and diffuse wheezing - is suggestive of beta blocker overdose. Intoxication with calcium channel blockers, digoxin, and cholinergic agents could also cause similar symptoms, but wheezing is more specific for beta blocker toxicity. The most common presentation is bradycardia and hypotension leading to cardiogenic shock, as evidenced by this patient's cold and clammy extremities. Other effects include hypoglycemia, bronchospasm/wheezing (beta 2 blockade), and neurological dysfunction (eg, delirium, seizures). The first steps in management are to secure the airway and give isotonic fluid boluses and intravenous (IV) atropine for initial treatment of hypotension and bradycardia. In patients with refractory or profound hypotension, the next step is to administer IV glucagon. Glucagon increases the intracellular levels of cyclic AMP and has been effective in treating both beta blocker and calcium channel blocker toxicity. Other therapies that can be used simultaneously or in succession include IV calcium, catecholamine vasopressors (epinephrine or norepinephrine), high-dose insulin and glucose, and IV lipid emulsion therapy (used to manage poisoning in lipophilic medications such as beta blockers). (Choice A) Aminophylline is a methylxanthine, which acts by blocking phosphodiesterase, thereby increasing levels of cyclic AMP. It causes bronchodilation and has positive inotropic/chronotropic effects, but has been used only experimentally in beta blocker toxicity. (Choice B) Digoxin-specific antibody (Fab) is the antidote for digoxin toxicity, which usually presents with fatigue, anorexia, nausea, blurred vision, disturbed color perception, and cardiac arrhythmias. Wheezing is not a feature of digoxin toxicity. digoxin toxicity (Choice C) Although dobutamine is an inotropic catecholamine that has beta agonist effects, its use is avoided in beta blocker overdose because it can cause significant vasodilation with resultant worsening hypotension; in general, although catecholamines (eg, epinephrine) are used in conjunction with other medications in beta blocker overdose, high doses are necessary, which increases the risk of arrhythmia. (Choice E) Temporary pacing can be used in patients with profound bradycardia. However, studies of pacing in the setting of severe beta blocker overdose have shown that pacing usually fails to capture, and even adequate capture (with increases in heart rate) rarely results in improved cardiac output and blood pressure. Educational objective: Beta blocker overdose presents with bradycardia, hypotension, wheezing, hypoglycemia, delirium, seizures, and cardiogenic shock. Intravenous fluids and atropine are the first-line treatment options. Intravenous glucagon should be administered in patients with profound or refractory hypotension. References: Pharmacology, pathophysiology and management of calcium channel blocker and beta-blocker toxicity. (http://www.ncbi.nlm.nih.gov/pubmed/15898828) Treatment of poisoning caused by beta-adrenergic and calcium-channel blockers. (http://www.ncbi.nlm.nih.gov/pubmed/16990629)

A 58-Year-Old Man Is Brought to the Emergency Department After