Non-circadian signals in the intensive care unit: Point prevalence morning, noon and night

Background: Intensive care unit (ICU) sleep disturbance is severe and potentially related to abnormal light and sound exposure.

Objectives: To assess the prevalence of measures of light and sound disturbance in ICU patient rooms, and whether these could be modified by a sleep-promotion intervention.

Methods: This observational study with a before and after design for a quality improvement initiative surveyed environmental factors in ICU rooms at 01:00 08:00, and 12:00. Surveys assessed light usage, television usage, window shade position, and room door/curtain position. Factors were compared before and after an ICU sleep-promotion intervention.

Results: 990 (pre-intervention) and 819 (post-intervention) occupied rooms were surveyed. Pre-intervention, the prevalence of night-time factors included: bright lights on (21%), television on (46%), and room door open (94%). Post-intervention, more rooms had all lights off at night (41% v 50%, p = 0.04), and fewer rooms had open door curtains (57% v 42%, p = 0.001) and window shades (78% v 62%, p = 0.002).

Conclusions: Disruptive environmental factors are common in the ICU. Some factors improve with sleep-promotion interventions.