Review of Cycled Lighting's Effect on Premature Infants' Circadian Rhythm Development and Clinical Outcomes Based on Gestational Age.

Abstract

Background: Circadian rhythm development is mediated by pre- and postnatal factors. Premature birth interrupts development and exposes neonates to abnormal stimuli. Cycled lighting is an encouraging technique to stimulate formation of a 24-hour biological rhythm.

Purpose: Review the literature regarding benefits of cycled lighting versus other lighting conditions for premature infants and evaluate the optimal gestational age for initiation.

Data sources: Search of PubMed, CINHAL, and Google Scholar from 2012 to 2023.

Study selection: Inclusion criteria covered effects of cycled lighting and focus on premature infants in the neonatal intensive care unit. Exclusion criteria were non-human studies and those that did not address the clinical question. Articles were limited to randomized controlled trials or systematic reviews. Sixteen articles were included in this review.

Results: Research found inconsistent support for cycled lighting depending on the age at initiation when assessing weight gain, quality of movement, sleep and activity rhythms, ventilator days, length of stay, time to oral feeding, and irritability.

Implications for practice: Infants should be kept in continuous near darkness until 32 weeks gestational age to promote sleep. Benefits from cycled lighting start to be seen between 32 and 34 weeks of gestation with light levels between 10 and 600 lux. Delaying initiation until 36 weeks has not been shown to be beneficial.

Implications for research: Future research should focus on stratifying infants based on gestational age at the time of initiation and consider the length of exposure time to cycled lighting while using larger sample sizes.