A 68-year-old man is evaluated in the intensive care unit for sudden-onset severe respirat… — USMLE Step 2 CK

A 68-year-old man is evaluated in the intensive care unit for sudden-onset severe respiratory distress that began 30 minutes ago. He was admitted two days ago for a large anterior ST-elevation myocardial infarction. His medical history includes hypertension and severe chronic obstructive pulmonary disease (COPD). The patient is sitting upright on the edge of the bed, visibly diaphoretic, and using accessory muscles of respiration. Vital signs are temperature $37.1^\circ C$ ( $98.8^\circ F$ ), blood pressure $165/95$ mm Hg, pulse $118$ /min, and respirations $30$ /min. Pulse oximetry shows an oxygen saturation of $84\%$ on room air. Physical examination reveals distended neck veins, a third heart sound (S3), and diffuse bilateral crackles on lung auscultation. An arterial blood gas on room air shows:

Parameter	Value	Reference Range
$pH$	$7.26$	$7.35-7.45$
$PaCO_2$	$58$ mm Hg	$35-45$ mm Hg
$HCO_3^-$	$25$ mEq/L	$22-28$ mEq/L
$PaO_2$	$52$ mm Hg	$75-105$ mm Hg

Which of the following are the most appropriate immediate medical interventions for this patient's acute respiratory failure? (Select all that apply)

Initiation of noninvasive positive pressure ventilationCevap
Administration of intravenous furosemideCevap
C
Administration of intravenous methylprednisolone
D
Administration of intravenous sodium bicarbonate
E
Administration of intravenous piperacillin-tazobactam

Cevap

The correct interventions are the initiation of noninvasive positive pressure ventilation and the administration of intravenous furosemide.

The patient is experiencing acute cardiogenic pulmonary edema secondary to a recent myocardial infarction, resulting in acute hypoxemic and hypercapnic respiratory failure. The administration of intravenous furosemide reduces volume overload, while the initiation of noninvasive positive pressure ventilation (NPPV) decreases the work of breathing, improves oxygenation by recruiting alveoli, and helps clear the acute respiratory acidosis.

Adım Adım Çözüm

Analyze the clinical presentation and physical exam findings.

The patient developed sudden respiratory distress two days after a large myocardial infarction. Findings include severe hypertension, tachycardia, JVD, an S3 gallop, and bilateral crackles.

These classic findings strongly indicate acute decompensated heart failure (ADHF) leading to cardiogenic pulmonary edema, superseding his history of COPD.

Interpret the arterial blood gas (ABG) results.

The ABG shows a

pH

7.26

, an elevated

PaCO_2

58

mm Hg, and a normal

HCO_3^-

25

mEq/L, along with severe hypoxemia (

PaO_2

52

mm Hg).

This confirms acute, uncompensated respiratory acidosis with severe hypoxemic respiratory failure secondary to alveolar flooding.

Determine the optimal immediate medical interventions.

The patient urgently requires preload reduction and ventilatory support. Intravenous furosemide and noninvasive positive pressure ventilation (NPPV) are selected.

Furosemide immediately reduces pulmonary congestion via venodilation and subsequent diuresis. NPPV improves oxygenation, decreases the work of breathing, and treats the respiratory acidosis by augmenting ventilation.

Anahtar Kavram

Acute decompensated heart failure presenting with cardiogenic pulmonary edema and acute respiratory acidosis requires immediate preload reduction (diuretics, vasodilators) and ventilatory support (NPPV), and must be differentiated from COPD exacerbations.

Soru

Cevap

Adım Adım Çözüm

Anahtar Kavram

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