Apnea and sleep state in infants with nasopharyngitis.

Having a mild upper respiratory tract infection does not change the sleep rate proportions or total sleep time of an infant. However, infants with colds exhibit some sleep state specific alterations in sleep apnea. At 40, 44, and 48 weeks postconception, the number of respiratory pauses of 2 to 4.9 seconds and of 5 to 9.9 seconds duration per 100 minutes of state, during rapid eye movement, and indeterminate sleep are decreased in infants with colds. The absence of this phenomenon at 52 weeks suggests that it is modified by maturation. We hypothesize that the reduction in rapid eye movement and indeterminate sleep apnea is a manifestation of an adaptive response in normal infants, but for infants at risk for the sudden infant death syndrome, this response may be overwhelmed, resulting in increased apnea and, in some instances, sudden infant death.