Effect of procedure light on the physiological responses of preterm infants

Aim: Current recommendations for illumination in the NICU state that procedure light should be controlled with a rheostat to protect infants from high illumination. However, overhead fluorescent lights without a dimmer switch are still used in Japan. The aim of this study was to assess the effects of three different procedure lighting conditions (fluorescent with on/off switch rapidly increasing the level of light [FRL], incandescent with on/off switch rapidly increasing the level of light [IRL], and incandescent with dimmer switch slowly increasing the level of light [ISL]) on the respiratory rate (RR) and oxygen saturation (SpO(2)) in preterm infants with or without oxygen therapy. Methods: Eight preterm infants, with a gestational age of 29-31 weeks, were included in a repeated randomized cross-over study. ANCOVAs, based on general linear mixed models, were used to examine physiological changes over time and across lighting conditions. In addition, the minimum SpO(2) values, after increasing the level of light, were classified into SpO(2) < 85%, SpO(2) = 86-91%, and SpO(2) >= 92% for each lighting condition. Results: With and without oxygen therapy, the RR and SpO(2) under the ISL were higher than under the FRL and IRL. SpO(2) < 85% was only observed under the FRL and SpO(2) = 86-91% was observed under the FRL and IRL. Conclusions: These data suggest that differences in the light conditions influence physiological responses in preterm infants and slowly increasing the level of light might make it easier for them to slowly adapt to high illumination and prevent declining SpO(2) values in neonates.