Obesity hypoventilation syndrome: The Daily PANCE Blueprint
Which of the following would you NOT expect to see in someone with obesity hypoventilation syndrome?
A. BMI >30
B. Daytime PaCO2 > 45 mmHg
C. Obstructive sleep apnea
D. Decreased serum bicarbonate
E. Hypoxemia (PaO2 <80 mmHg)
Answer and topic summary
The answer is D. Decreased serum bicarbonate
Obesity hypoventilation syndrome (OHS) is a combination of obesity and daytime hypercapnia (due to alveolar hypoventilation) in the absence of other causes. Clinical features include elevated BMI (>30), high carbon dioxide levels (PACO2 > 45mmHg), elevated serum bicarbonate (>27 mEq/L due to kidneys trying to compensate for a primary respiratory acidosis), hypoxemia (PaO2 <70mmHg), polycythemia, and sleep-related breathing disorders (e.g., OSA). Workup includes overnight polysomnography and daytime ABG. Management is weight loss and positive airway pressure at night.
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Smarty PANCE Content Blueprint Review:
Covered under ⇒ PANCE Blueprint Pulmonary ⇒
Also covered in the Internal Medicine PAEA EOR content blueprint
