SLEEP-WAKING PATTERNS IN HYPOXIC KITTENS

Sleep apnea was proposed as a mechanism of respiratory failure in Sudden Infant Death Syndrome. Kittens at 10, 20 and 40 days of age were made intermittently hypoxic in 10 or 7% O2 chambers for either 3 or 8 days. Respiration, ECG, EEG, and neck and eye movements were recorded during hypoxia. Compared to 21% O2 controls hypoxic kittens had fewer and shorter epochs of active sleep and longer epochs of quiet sleep. Some hypoxic kittens exhibited slow and labored respiration during quiet sleep and transitional epochs, which reversed during active sleep. Kittens that showed most pronounced respiratory changes or died had less active sleep than kittens that compensated adequately and survived. Active sleep may be important for stimulation of respiration during human infancy. Suppression of active sleep, augmentation of quiet sleep or other disturbances to normal sleep-waking patterns during hypoxia, may increase the risk for hypoxic respiratory depression and death.