Breathing, sleep, and diabetic autonomic neuropathy.

Sudden, unexplained deaths are relatively common in diabetic autonomic neuropathy. As disturbed autonomic function has been associated with sleep apnea, and sleep apnea with sudden death, we recorded breathing patterns, arterial oxygen saturation, and EEG during sleep in 8 male diabetic subjects with severe autonomic neuropathy and 8 age-matched, male diabetic subjects without autonomic neuropathy. None of the patients with autonomic neuropathy had more than 11 apneic episodes per night, and there were no significant differences between the two groups in the number of sleep apneas, the duration of individual apneic episodes, the total duration of irregular breathing during sleep, or the duration and quality of sleep. The arterial oxygen saturation when awake and the lowest arterial oxygen saturation during sleep were also similar in both groups. Thus, diabetic patients with severe autonomic neuropathy have normal breathing patterns and oxygenation during sleep, and it is unlikely that sleep apnea causes these unexpected deaths.