Lack of effect of external warming on sleep architecture in sleep apnea/hypopnea syndrome.

Sleep apnea/hypopnea syndrome (SAHS) is characterized by nocturnal apneas (A) and/or hypopneas (H) occurring in various sleep stages. However, these disordered breathing events (DBE) occur rarely in slow-wave sleep (SWS) and are most severe in rapid eye movement (REM) sleep when severe hypoxemia results. Several studies have shown that a rise in body temperature by external warming, induced according to a specific protocol, affects normal human sleep architecture by diminishing the time spent in REM and increasing the time spent in SWS. The purpose of this study was to determine if external warming is as effective in sleep apneic patients in decreasing REM and increasing SWS, hoping that DBE and hypoxemia may diminish. Seven newly diagnosed patients were studied two more nights, on one of which (selected randomly) the sleep study was preceded by sitting in a warm bathtub with temperature of 41 degrees C for 1/2 h, 2 1/2 h before the start of sleep study. The mean maximum rise in oral temperature with warm bath was 2.0 +/- 0.4 degrees C. Total bed time (min) and sleep efficiency, REM, and SWS (%) were, respectively, 320 +/- 17 (SD), 81 +/- 8, 19 +/- 7, and 1.2 +/- 1.1 for the control (C) and 339 +/- 33, 79 +/- 11, 19 +/- 5, and 2.4 +/- 1.6 for the bath (B) night. In both C and B, the lowest O2 saturation (%) occurred in REM sleep and was 78 +/- 7 and 77 +/- 9, respectively. Comparing respective paired values between C and B, no significance was found.(ABSTRACT TRUNCATED AT 250 WORDS)