Stuck in the Dark: No Association between Light, Sound, and Delirium in the PICU

Objectives: The purpose of this study was to evaluate the association between sound and light variables and development of delirium in pediatric intensive care unit (PICU) patients within the subsequent three days. Methods: Light and sound were continuously measured, and patient-specific data was collected daily. Outcomes included presence of delirium, determined by Cornell Assessment of Pediatric Delirium (CAPD) score ≥ 9 on at least one day, and development of delirium in the subsequent 3 days. Results: 142 patients were enrolled, totaling 896 study days. Delirium prevalence was 31%. Neurologic diagnosis, younger age, longer PICU stay, restraints, benzodiazepines, opiate infusion, and dexmedetomidine were associated with delirium. Nighttime sound peaks (>70 and >80dB) were not associated with delirium (p=0.94 and 0.36, respectively). Light intensity during midday hours was not associated with development of delirium (p=0.93, 0.81, 0.83, respectively), nor was maximum light at night, difference between maximum daytime and nighttime light, or between maximum and minimum daytime light (p=0.15, 0.46 and 0.96, respectively). When adjusting for co-variables, none of the sound or light variables was associated with delirium. Conclusions: Despite increasing awareness of pediatric delirium, data surrounding modifiable risk factors and concrete treatment strategies is lacking. We found no significant association between light or sound and development of delirium in PICU patients. However, there was little difference between daytime and nighttime light and sound, which may have impacted findings. As the etiology of delirium is multifactorial and potentially different for individual patients, targeted light/dark cycles warrant further study as they relate to delirium and critical illness.