An emergency medical services team brings a 76-year-old male to the hospital at 2:00\text{… — USMLE Step 2 CK

An emergency medical services team brings a $76$ -year-old male to the hospital at $2:00\text{ AM}$ due to abrupt, severe respiratory distress. The patient has a known history of ischemic heart disease and hypertension. His wife reports that he woke up suddenly, gasping for air, and has been expectorating frothy, pink-tinged sputum. Over the preceding week, he had transitioned to sleeping in a living room recliner due to worsening dyspnea when lying flat. He is a lifetime non-smoker. Upon arrival, his vital signs include a temperature of $36.8^\circ\text{C}$ ( $98.2^\circ\text{F}$ ), blood pressure of $185/105\text{ mmHg}$ , a regular heart rate of $115\text{/min}$ , and a respiratory rate of $28\text{/min}$ . Pulse oximetry indicates an oxygen saturation of $86\%$ on room air. The patient appears highly anxious, diaphoretic, and is leaning forward while utilizing accessory respiratory muscles. Lung auscultation is notable for loud, diffuse expiratory wheezes bilaterally, alongside faint crackles restricted to the posterior bases. Cardiac examination reveals a distinct S3 gallop. An electrocardiogram exhibits sinus tachycardia with established Q waves in leads $\text{V}_1$ through $\text{V}_4$ . Arterial blood gas analysis on room air demonstrates a $\text{pH}$ of $7.48$ , $\text{PaCO}_2$ of $30\text{ mmHg}$ , $\text{PaO}_2$ of $55\text{ mmHg}$ , and $\text{HCO}_3^-$ of $22\text{ mEq/L}$ . Which of the following represents the most appropriate initial pharmacological approach to address this patient's acute symptoms?

A
Administration of nebulized short-acting beta-agonists and systemic glucocorticoids
B
Intravenous administration of sodium bicarbonate
Intravenous administration of a loop diuretic and a vasodilatorCevap
D
Intravenous administration of a broad-spectrum cephalosporin and a macrolide
E
Administration of nebulized anticholinergic agents and targeted low-flow oxygen therapy

Cevap

Intravenous administration of a loop diuretic and a vasodilator

The correct approach addresses the patient's acute decompensated heart failure (ADHF) presenting as pulmonary edema. Despite the prominent, diffuse wheezing, the patient's history of ischemic heart disease, new-onset orthopnea, expectoration of frothy pink sputum, and the presence of an S3 gallop confirm a cardiogenic etiology, often referred to clinically as 'cardiac asthma'. The severe hypertension (

185/105\text{ mmHg}

) indicates a significantly increased afterload that is contributing to left ventricular failure. The most appropriate initial pharmacological strategy involves simultaneous preload and afterload reduction using an intravenous loop diuretic (e.g., furosemide) and a rapid-acting vasodilator (e.g., nitroglycerin), alongside supplemental oxygen.

Adım Adım Çözüm

Analyze the patient's presenting symptoms and vital signs.

The patient is experiencing acute, severe respiratory distress with profound hypoxia (

86\%

on room air), significant hypertension (

185/105\text{ mmHg}

), and prominent wheezing.

Establishing the severity and acuity of the presentation is necessary to prioritize initial life-saving interventions.

Evaluate the patient's medical history and specific physical examination findings.

The history of ischemic heart disease, orthopnea, expectoration of frothy pink sputum, and an S3 gallop strongly point to a cardiogenic etiology.

Differentiating between pulmonary and cardiovascular causes of acute wheezing ('cardiac asthma' vs. primary asthma/COPD) requires synthesizing specific historical clues and cardiac signs.

Interpret the objective diagnostic data.

The electrocardiogram shows established anterior ischemic changes. The arterial blood gas indicates a primary respiratory alkalosis (

\text{pH } 7.48

, low

\text{PaCO}_2

) driven by hypoxia, ruling out the acute hypercapnic respiratory acidosis commonly seen in severe COPD exacerbations.

Objective data confirms the diagnosis of acute cardiogenic pulmonary edema and excludes mixed or alternative metabolic derangements.

Determine the most appropriate pharmacological management.

Given the cardiogenic origin (acute decompensated heart failure) coupled with severe hypertension, aggressive preload and afterload reduction are required.

Loop diuretics remove excess intravascular fluid volume, and vasodilators rapidly lower blood pressure, effectively relieving pulmonary congestion.

Anahtar Kavram

Cardiac asthma is a presentation of acute decompensated heart failure that can mimic primary pulmonary disease due to peribronchial edema causing severe wheezing; management strictly requires diuretics and vasodilators rather than standard bronchodilator therapy.

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