Why excessive sleepiness may persist in OSA patients receiving adequate CPAP treatment

From the authors: P. Castiglioni and co-workers suggest that residual excessive sleepiness (RES) in patients with obstructive sleep apnoea (OSA) who are adequately treated with nasal positive airway pressure may be caused by a concomitant, untreated hypercapnia (if OSA overlaps with obesity hypoventilation syndrome or with chronic obstructive pulmonary disease) or by persistent autonomic subcortical arousals. We examined with interest both hypotheses, but neither fits our series [1]. Concomitant chronic obstructive pulmonary disease was a criterion for exclusion (as was any medical disease that could cause sleepiness per se ), after …