A 72-year-old man is brought to the emergency department due to the sudden onset of severe… — USMLE Step 2 CK

A 72-year-old man is brought to the emergency department due to the sudden onset of severe shortness of breath and a cough productive of pink, frothy sputum that began $1$ hour ago. He has a history of ischemic cardiomyopathy with a left ventricular ejection fraction of $35\%$ , mild chronic obstructive pulmonary disease (COPD), and poorly controlled hypertension. His current medications include lisinopril, metoprolol succinate, aspirin, and a tiotropium inhaler. His temperature is $37.0^\circ\text{C}$ ( $98.6^\circ\text{F}$ ), blood pressure is $220/120$ mmHg, pulse is $115$ /min, and respirations are $32$ /min. Pulse oximetry shows $84\%$ on room air. The patient is alert, oriented, and speaks in short, gasping phrases. Physical examination reveals use of accessory muscles of respiration. Auscultation of the lungs reveals diffuse, high-pitched expiratory wheezes bilaterally with no audible crackles. Cardiovascular examination reveals a regular tachycardia with a prominent $S_4$ gallop. There is no jugular venous distention or lower extremity edema. An arterial blood gas analysis on room air shows:

Laboratory Parameter	Result
pH	$7.25$
PaCO $_2$	$65$ mmHg
PaO $_2$	$50$ mmHg
HCO $_3^-$	$28$ mEq/L

Which of the following is the most appropriate next step in management?

A
Inhaled albuterol and intravenous methylprednisolone
B
Intravenous ceftriaxone and azithromycin
C
Intravenous metoprolol and furosemide
Noninvasive positive pressure ventilation and intravenous nitroglycerinAnswer
E
Immediate endotracheal intubation

Answer

The correct intervention is noninvasive positive pressure ventilation (NIPPV) and intravenous nitroglycerin.

The patient is experiencing Sympathetic Crashing Acute Pulmonary Edema (SCAPE), a severe form of acute decompensated heart failure characterized by abrupt, extreme hypertension and flash pulmonary edema. The rapid accumulation of fluid in the peribronchial spaces compresses the airways, leading to expiratory wheezing known as 'cardiac asthma.' This must be differentiated from a COPD exacerbation. The presence of sudden-onset severe hypertension, pink frothy sputum, and an S4 gallop strongly supports a cardiogenic etiology rather than a primary pulmonary process. In SCAPE, the extreme afterload drives fluid into the alveoli. The immediate treatment goals are to reduce afterload and decrease the work of breathing. Noninvasive positive pressure ventilation (NIPPV) provides positive end-expiratory pressure, which splints airways open, improves oxygenation, and reduces both preload and afterload. Intravenous nitroglycerin acts as a rapid vasodilator, primarily reducing afterload at high doses, making it the ideal pharmacologic agent to break the cycle of sympathetic overtone.

Step-by-Step Solution

Analyze the clinical presentation and vital signs.

The patient presents with severe hypertension (

220/120

mmHg), hypoxia, respiratory acidosis, pink frothy sputum, and an

S_4

gallop.

Identifying the constellation of extreme hypertension and abrupt respiratory failure establishes the diagnosis of flash pulmonary edema.

Differentiate the cause of wheezing.

The wheezing is recognized as 'cardiac asthma' caused by peribronchial edema, rather than a primary COPD exacerbation.

Although the patient has a history of COPD, the lack of fever, presence of a new

S_4

, and pink frothy sputum rule out an infectious pulmonary exacerbation.

Determine the optimal immediate therapeutic interventions.

Select NIPPV for respiratory support and IV nitroglycerin for rapid blood pressure control.

In Sympathetic Crashing Acute Pulmonary Edema (SCAPE), reducing extreme afterload is the primary mechanism to halt fluid shift into the alveoli, while NIPPV splints the airways open.

Key Concept

Differentiating cardiac asthma from COPD exacerbation and managing Sympathetic Crashing Acute Pulmonary Edema (SCAPE) with rapid afterload reduction and NIPPV.

Question

Answer

Step-by-Step Solution

Key Concept

Common Mistakes

Topics

More questions from this topic