Intradialytic subjective sleepiness and oral body temperature

Study Objectives: Hemodialysis (HD) patients are often observed to sleep du ring treatment. Because of the well-described, inverse association between body temperature and sleep propensity, the purpose of this study was to des cribe the course of intradialytic (during HD) subjective sleepiness and exa mine its relationship to oral body temperature. In addition, we sought to d etermine if that relationship varied with dialysis treatment time of day. Design: Subjective sleepiness and oral body temperature were recorded every 15 minutes through the entire course of HD. Setting: The study was conducted at two large, inner-city dialysis units. Patients or Participants: The sample included 60 chronic HD patients, 20 on each of three shifts based on treatment time of day (shift 1-6:00A.M, to 1 0:00A.M.; shift 2-10:00A.M, to 2:00P.M.; and shift 3-2:00P.M, to 6:00P.M.. Measurements and Results: Subjects on shift 1 were found to have a mean int radialytic sleepiness level greater than those on shift 2 (p<.04) and shift 3 (p<.003). Irrespective of shift, sleepiness increased during the first h alf of dialysis and decreased slightly as treatment progressed, a significa nt quadratic trend (p<.001). During the same period, temperature initially increased, subsequently dropped in temporal proximity to maximal sleepiness and increased again, a significant quadratic trend (p<.02). The relationsh ip between sleepiness and temperature revealed a significant negative corre lation (r=-.59, p<.03) and did not vary with treatment time of day. Conclusions: The results argue that sleep propensity increases during HD, a n effect that may be related to treatment induced alterations in arousal an d/or thermoregulatory processes. The effect is unrelated to treatment time of day.