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Difficulty: Very hardCardiovascular System

A 68-year-old man is brought to the emergency department by emergency medical services due to severe, acute-onset shortness of breath and chest tightness that awoke him from sleep 1 hour ago. He has a history of ischemic cardiomyopathy with a left ventricular ejection fraction of 35%, chronic obstructive pulmonary disease, hypertension, and erectile dysfunction. His current medications include aspirin, lisinopril, carvedilol, tiotropium, and sildenafil. He reports taking a dose of sildenafil 10 hours ago. The patient is diaphoretic and in severe respiratory distress, struggling to speak in full sentences. His temperature is 37.1°C (98.8°F), blood pressure is 210/115 mmHg, pulse is 115/min, and respiratory rate is 32/min with an oxygen saturation of 84% on room air. Physical examination reveals jugular venous distension 12 cm above the sternal angle. Cardiac auscultation reveals a regular tachycardia with a prominent S3 gallop. Lung auscultation reveals diffuse bilateral expiratory wheezes and crackles at the lung bases. Electrocardiogram shows sinus tachycardia with left ventricular hypertrophy and non-specific ST-segment changes. Which of the following is the most appropriate next step in management?

  1. Application of non-invasive positive pressure ventilation and administration of intravenous furosemideAnswer
  2. B
    Administration of intravenous nitroglycerin and intravenous furosemide
  3. C
    Administration of nebulized albuterol, ipratropium, and intravenous methylprednisolone
  4. D
    Administration of intravenous metoprolol and non-invasive positive pressure ventilation
  5. E
    Immediate endotracheal intubation and administration of intravenous furosemide

Answer

Application of non-invasive positive pressure ventilation and administration of intravenous furosemide
The patient presents with sympathetic crashing acute pulmonary edema, a form of acute decompensated heart failure (ADHF) characterized by acute severe hypertension, respiratory distress, and flash pulmonary edema. The wheezing represents 'cardiac asthma' resulting from peribronchial edema. The immediate goals of therapy are to improve oxygenation and reduce ventricular preload and afterload. Non-invasive positive pressure ventilation (NIPPV) is the ideal first-line respiratory support because it decreases the work of breathing, improves oxygenation, and beneficially decreases both left ventricular preload and afterload. Intravenous loop diuretics (such as furosemide) are indicated to assist with fluid offloading. Although intravenous vasodilators, primarily nitroglycerin, are standard therapy for rapid afterload reduction in hypertensive ADHF, they are strictly contraindicated in this patient. The patient ingested sildenafil, a phosphodiesterase-5 (PDE-5) inhibitor, 10 hours ago. PDE-5 inhibitors block the degradation of cyclic GMP (cGMP), while nitrates increase the production of cGMP via nitric oxide. Co-administering these medications within 24 hours leads to massive cGMP accumulation, resulting in profound and potentially fatal hypotension. Therefore, combining NIPPV with intravenous furosemide provides safe and effective preload and afterload reduction without risking a catastrophic drug interaction.

Step-by-Step Solution

1
Diagnose the primary cause of acute respiratory distress based on clinical findings.
Acute decompensated heart failure (sympathetic crashing acute pulmonary edema).
The presence of severe hypertension, hypoxia, orthopnea, an S3 gallop, JVD, and bibasilar crackles points to a cardiogenic etiology. The wheezing represents cardiac asthma, not a primary COPD exacerbation.
2
Review the patient's medication history for potential drug interactions before initiating standard heart failure therapy.
The patient took sildenafil 10 hours ago.
Standard therapy for hypertensive acute pulmonary edema includes afterload reduction with nitrates (e.g., nitroglycerin). However, nitrates are absolutely contraindicated within 24 hours of sildenafil use.
3
Determine the safest and most effective alternative interventions for immediate stabilization.
Initiate non-invasive positive pressure ventilation (NIPPV) and administer intravenous loop diuretics.
NIPPV rapidly improves oxygenation and decreases both left ventricular preload and afterload, serving as a non-pharmacologic afterload reducer. Furosemide aids in volume offloading without interacting with PDE-5 inhibitors.

Key Concept

Management of acute decompensated heart failure with concurrent phosphodiesterase-5 inhibitor use
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Topics

Cardiovascular System

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