LAUSR

Pediatric patients undergoing stem cell transplant (SCT) often experience extended hospitalizations. Inappropriate lighting during admissions is known to disrupt sleep and circadian health, which can result in worse health outcomes. This study aimed to describe patterns of light across 24-hour periods in two inpatient rooms of children undergoing SCT. Wall-mounted light meters (Extech SDL400) continuously tracked noise and light levels at one-minute intervals in two patient rooms over six months. We determined the percent of time that patients were exposed to non-optimal light levels (< 448 lux during the daytime, >18 lux in the evening, >2 lux at night); thresholds were based on converting recent consensus-based melanopic equivalent daylight illuminance guidelines to vertically measured illuminance thresholds. We assessed the frequency that light exceeded thresholds associated with night wakings (>150 lux). Wilcoxon rank-sum tests compared light levels between the two rooms. Room A had a single northwest-facing window overlooking a narrow courtyard. Room B had an unobstructed window facing north. On average, hospitalized pediatric SCT patients spent 50% of their time in inappropriate light conditions. They were exposed to light spikes >150 lux on 2% of nights, with overnight light peaking at 513 lux. When comparing average daytime and nighttime light levels between the two rooms, Room A was significantly dimmer than Room B, p <.001. In the dimmer room, light levels never reached the recommended threshold during the daytime, and the light was too bright for 19% of the evening and 17% of the nighttime. In the brighter room, light levels were too dim during 97% of the daytime and too bright during 59% of the evening and 30% of the nighttime. During the day, pediatric SCT patients are rarely exposed to light bright enough to preserve a healthy circadian rhythm. Hospitals have an opportunity to significantly improve the sleep and circadian health for children already at elevated risk for health morbidities during transplant. This research was generously supported by grant funding from Pedals for Pediatrics (PI: Zhou) and an institutional research training grant (T32DK063929).