Kaplan USMLE Step 3: Manage this patient's respiratory symptoms

A 72-year-old man with a history of coronary artery disease, chronic obstructive pulmonary disease (COPD) and stroke is admitted to the intermediate-level intensive care unit after developing increasing dyspnea and sputum production over the past 3 days. Prior to these symptoms, he had several days of a sore throat, nasal congestion and rhinorrhea.

His temperature is 37.2ºC (99ºF), pulse is 105/min, and respirations are 28/min. On examination, he is acutely short of breath and is actively using accessory muscles of respiration. Chest auscultation reveals decreased breath sounds throughout and prominent end-expiratory wheezing. His oxygen saturation is 89% while breathing room air, which rises to 94% on 3 L/min of oxygen via nasal cannula. Routine chemistries and complete blood count are normal. Arterial blood gas testing reveals the following:

• pH: 7.22
• PaCO₂: 64 mm Hg
• PaO₂: 86 mm Hg

An electrocardiogram shows sinus tachycardia with bilateral atrial enlargement. A chest radiograph shows hyperinflation but no infiltrate or edema.

Which of the following will most likely decrease the need for endotracheal intubation and decrease mortality in this patient?

A. Broad-spectrum antibiotics

B. High-dose systemic corticosteroids

C. Inhaled corticosteroids

D. Intravenous theophylline

E. Non-invasive positive-pressure ventilation

The correct answer is E.

This patient is experiencing a chronic obstructive pulmonary disease (COPD) exacerbation, a common event that often follows a viral upper respiratory tract infection. The cornerstones of therapy are inhaled bronchodilators and supplemental oxygen as needed to correct hypoxemia. Several recent randomized trials have also demonstrated the ability of non-invasive positive-pressure ventilation (NIPPV) to decrease mortality and the need for endotracheal intubation in this setting. This mode of ventilation involves a tight-fitting nasal mask that generates positive end-expiratory pressure, splinting open airways and preventing dynamic airway collapse. This modality decreases the work of breathing and helps correct respiratory acidosis (patients with pH <7.35, PaCO₂ >45 mm Hg, respiratory fatigue, moderate to severe dyspnea, or respiratory rate greater than 25/min).

Choice A. The evidence is somewhat more equivocal regarding broad-spectrum antibiotics in COPD exacerbations. General consensus on the basis of randomized, controlled trials is that in patients with an increase in sputum production or a change in the quality of sputum, antibiotics may offer a small benefit. Time to resolution is decreased, but there is no change in overall mortality.

Choice B. Symptoms and clinical markers in COPD exacerbations also resolve more quickly with systemic corticosteroids, although there is no apparent mortality benefit. Again, the benefits are modest.