Tracheal occlusion in the newborn piglet. Effects of sleep state and occlusion timing on arousal and respiratory responses

Abstract

Twelve piglets of 3-5 days of age were instrumented for determination of sleep state and performance of midtracheal occlusions. After spontaneously occurring sleep the occlusions were performed either at end-inspiration or end-expiration in quiet and active sleep. The time from occlusion to arousal differed significantly between quiet and active sleep. Arousal from quiet sleep following end-expiratory occlusions occurred after a mean of 3.1 s. After similar, end-expiratory occlusions in quiet sleep were commonly followed by apneas, presumably a manifestation of the Hering-Breuer reflex. Such apneas were rare in active sleep (P less than 0.01). The arousal response to midtracheal occlusions in the newborn piglet is qualitatively similar to that previously described in the newborn lamb, but occurs more rapidly. Our results suggest that the response to vaguely mediated information from pulmonary stretch receptors is impaired inactive sleep.