ABEM Cardiovascular & Respiratory Emergencies 5 — Questions and Answers
Question 1: A patient presents with narrow-complex tachycardia at 160 bpm, regular rhythm, and hemodynamic stability. Vagal maneuvers fail. What is the FIRST-LINE pharmacologic treatment?
- Amiodarone 150mg IV
- Adenosine 6mg rapid IV push (Correct answer)
- Diltiazem 0.25 mg/kg IV
- Metoprolol 5mg IV
Correct answer: Adenosine 6mg rapid IV push
Adenosine 6mg rapid IV push is first-line for stable SVT because it transiently blocks AV nodal conduction and terminates re-entry circuits.
Question 2: A patient with end-stage renal disease presents with peaked T-waves, widening QRS, and a sine-wave pattern on ECG. The MOST immediately life-saving treatment is:
- Sodium bicarbonate IV
- Calcium gluconate IV (Correct answer)
- Insulin + glucose IV
- Kayexalate PO
Correct answer: Calcium gluconate IV
Calcium gluconate immediately stabilizes the cardiac membrane in severe hyperkalemia, buying time while other measures to lower potassium are implemented.
Question 3: Which clinical sign differentiates obstructive shock from distributive shock?
- Tachycardia
- Hypotension
- Cool, clamped extremities with elevated JVP (Correct answer)
- Widened pulse pressure
Correct answer: Cool, clamped extremities with elevated JVP
Obstructive shock (e.g., PE, tamponade, tension pneumothorax) presents with elevated JVP and cool extremities due to mechanical obstruction impeding cardiac output.
Question 4: A 65-year-old smoker with known COPD presents in respiratory failure. ABG shows pH 7.22, PaCO2 78, PaO2 52. The MOST appropriate initial ventilatory support is:
- High-flow nasal cannula at 60 L/min
- Non-invasive positive pressure ventilation (BiPAP) (Correct answer)
- Immediate orotracheal intubation
- Simple face mask at 10 L/min
Correct answer: Non-invasive positive pressure ventilation (BiPAP)
BiPAP is the preferred initial ventilatory support for COPD exacerbation with hypercapnic respiratory failure as it reduces intubation rates and mortality.
Question 5: A previously healthy 30-year-old male presents with sudden pleuritic chest pain and dyspnea after lifting weights. CXR shows a 25% pneumothorax on the right. He is hemodynamically stable. Management is:
- Supplemental O2 and discharge with follow-up
- Needle aspiration or small-bore chest tube (Correct answer)
- Large-bore chest tube (28-32 Fr)
- Observation only without oxygen
Correct answer: Needle aspiration or small-bore chest tube
A symptomatic primary spontaneous pneumothorax >15-20% in a stable patient is treated with needle aspiration or small-bore chest tube placement.
Question 6: A 68-year-old woman presents with acute decompensated heart failure and severe dyspnea. Despite diuretics and nitroglycerin, she remains hypoxic with SpO2 86%. The BEST next step is:
- Increase the dose of furosemide
- Apply CPAP via non-invasive ventilation (Correct answer)
- Start dobutamine infusion
- Administer IV morphine 4mg
Correct answer: Apply CPAP via non-invasive ventilation
CPAP reduces work of breathing, improves oxygenation, and decreases preload in acute cardiogenic pulmonary edema, reducing intubation rates.
Question 7: Which ECG finding during SVT suggests the rhythm is atrial flutter rather than AVNRT?
- Regular narrow QRS complexes
- Sawtooth flutter waves at 300 bpm in leads II, III, aVF (Correct answer)
- No visible P waves
- Retrograde P waves immediately after QRS
Correct answer: Sawtooth flutter waves at 300 bpm in leads II, III, aVF
Atrial flutter characteristically shows sawtooth flutter waves at approximately 300 bpm (atrial rate) in inferior leads, often with 2:1 AV conduction giving a ventricular rate of 150 bpm.
ABEM Cardiovascular & Respiratory Emergencies 5
A patient presents with narrow-complex tachycardia at 160 bpm, regular rhythm, and hemodynamic stability.
Vagal maneuvers fail.
What is the FIRST-LINE pharmacologic treatment?