The effect of environmental lighting on the oxygen saturation of preterm infants in the NICU.

The premature infant is more vulnerable to the NICU environment than a full-term infant due to neurologic immaturity and physiologic instability. Studies have been done on the effects of long-term decreases in environmental light, but none have been done on the immediate effects. The purpose of this study was to determine the relationship between immediate changes in environmental illumination and oxygen saturation in preterm neonates and whether these were affected by gestational and postnatal age. The oxygen saturations of 27 sleeping infants (2 to 56 days of age) between 26 and 37 weeks gestation were continuously recorded for 40 minutes utilizing a Nellcor N200 oximeter. After recording baseline saturations for 5 minutes with the room lights at 100 footcandles, the illumination level was lowered to 5 footcandles. At the end of 30 minutes, lights were increased to the previous level. Oxygen saturations were recorded at one and five minutes after illumination decreases and increases. There was a statistically significant interaction between repeated measures of saturation at baseline and one and five minutes after lights were increased and covariates gestational, corrected gestational, and postnatal age (p = .02, p = .008, p = .005). Repeated measure analysis of covariance (ANCOVA) revealed no statistically significant changes in oxygen saturations after the lights had been lowered for babies who were younger in gestational or postnatal age. The results of this study suggest that rapidly increasing illumination may be a cause of stress to the younger gestationally and postnatally preterm neonate.