To the Editor.
—In the October 1982 issue of the Archives (142:1816-1819), White et al reported on the beneficial effects of acetazolamide in treating central sleep apnea. We recently studied a patient with sleep apnea who exhibited all of the episodes of the central type with symptoms of excessive daytime somnolence (EDS), an apnea index of 17 apneas per hour and a desaturation from a baseline of 97% to a nadir of 86% during nonrapid eye movement (REM) sleep. The patient was treated with 250 mg of acetazolamide three times daily for five days, which decreased his serum bicarbonate ion level from 30 to 18 mEq/L and his serum pH to 7.38. His symptoms of EDS, however, worsened, and repeated study showed primarily obstructive apnea (80%) with some mixed episodes (20%). The apnea index had declined to 10 apneic episodes per hour, and maximal desaturation had decreased to 89%. The