Q: Should we routinely screen for hypercapnia in sleep apnea patients before elective noncardiac surgery?

OHS is also known as Pickwickian syndrome, named for a character—a “fat boy” who is constantly falling asleep—in The Posthumous Papers of the Pickwick Club by Charles Dickens. Salient features of OHS are: Obesity (body mass index ≥ 30 kg/m • 2) Sleep-disordered breathing (most patients with • OHS are morbidly obese and have severe obstructive sleep apnea1) Chronic daytime alveolar hypoventilation: ie, Pa • co2 ≥ 45 mm Hg (normal range 35–45 mm Hg) and Pao2 < 70 mm Hg1 (normal range 85–95 mm Hg) No other identifiable cause of hypoventilation • such as pulmonary disease (severe obstructive or restrictive), chest wall deformities, severe hypothyroidism, or neuro muscular disease. why screen for ohs? ■