A 71-year-old man is brought to the emergency department due to progressively worsening sh… — USMLE Step 2 CK

A $71$ -year-old man is brought to the emergency department due to progressively worsening shortness of breath and an increased volume of thick, purulent sputum over the past $48$ hours. His medical history is significant for severe chronic obstructive pulmonary disease (COPD), ischemic heart disease, and stage 3 chronic kidney disease. Vital signs show a temperature of $37.6^\circ\text{C}$ ( $99.7^\circ\text{F}$ ), heart rate of $112$ /min, respiratory rate of $26$ /min, and blood pressure of $155/88$ mm Hg. Oxygen saturation is $86\%$ on room air.

On physical examination, the patient appears somnolent but arouses to verbal stimuli. Jugular venous pressure is estimated at $7$ cm H $_2$ O. Chest auscultation reveals a markedly prolonged expiratory phase with diffuse bilateral wheezes and coarse rhonchi. No S3 gallop is appreciated. Bilateral 1+ pitting edema is present in the lower extremities.

An arterial blood gas analysis on room air reveals:

Laboratory Test	Result
pH	$7.28$
PaCO $_2$	$72$ mm Hg
PaO $_2$	$52$ mm Hg
HCO $_3^-$	$32$ mEq/L

A chest radiograph shows hyperlucent lung fields and flattened hemidiaphragms without focal consolidations or pleural effusions. A sputum Gram stain shows abundant polymorphonuclear leukocytes and Gram-negative coccobacilli.

Based on the clinical presentation and laboratory findings, which of the following are appropriate initial management steps for this patient? (Select all that apply)

Initiate noninvasive positive-pressure ventilation (NIPPV)Answer
Prescribe a short course of oral systemic glucocorticoidsAnswer
C
Administer intravenous furosemide
D
Administer intravenous piperacillin-tazobactam and vancomycin
E
Administer an intravenous sodium bicarbonate infusion

Answer

The correct management steps are to initiate noninvasive positive-pressure ventilation (NIPPV) and to prescribe a short course of oral systemic glucocorticoids.

This patient is experiencing a severe acute exacerbation of COPD, complicated by acute-on-chronic hypercapnic respiratory failure (indicated by a pH of

7.28

, PaCO

_2

72

mm Hg, and elevated baseline bicarbonate) along with mild CO

_2

narcosis (somnolence). The standard of care for COPD patients presenting with a pH

< 7.35

and PaCO

_2

> 45

mm Hg is the prompt initiation of noninvasive positive-pressure ventilation (NIPPV). NIPPV improves alveolar ventilation, reduces the work of breathing, and has been proven to decrease both mortality and the need for endotracheal intubation. Concurrently, systemic glucocorticoids (such as oral prednisone or intravenous methylprednisolone) are indicated in all severe COPD exacerbations to rapidly reduce airway inflammation, improve forced expiratory volume, and shorten recovery time.

Step-by-Step Solution

Analyze the patient's clinical presentation and acid-base status.

The patient is experiencing an acute exacerbation of COPD with acute-on-chronic hypercapnic respiratory failure, indicated by a pH of 7.28, PaCO2 of 72 mm Hg, and mild encephalopathy (somnolence).

Accurately identifying the primary physiological derangement and its severity dictates the urgency and modality of respiratory support.

Determine the most appropriate respiratory intervention.

NIPPV is strongly indicated as the first-line respiratory support.

NIPPV is the standard of care for COPD exacerbations complicated by respiratory acidosis (pH < 7.35 and PaCO2 > 45 mm Hg), significantly reducing mortality and the need for invasive endotracheal intubation.

Select the appropriate pharmacologic therapies for a severe COPD exacerbation.

Systemic glucocorticoids and targeted antibiotics should be administered.

Glucocorticoids reduce airway inflammation and accelerate clinical recovery. Antibiotics are indicated due to the presence of all three cardinal symptoms (increased dyspnea, sputum volume, and sputum purulence), but should target typical community-acquired organisms rather than utilizing empiric broad-spectrum coverage.

Key Concept

Management of acute exacerbations of COPD complicated by acute-on-chronic hypercapnic respiratory failure.

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