Quantifying sleep wake rhythms in the hospital environment with digital technologies

Postoperative clinical care is prone to circadian desynchronization that may influence health outcomes. In an exploratory, feasibility-oriented and signal-exploration effort, we collected 1.8 million data points using 11 remote sensors during preoperative, in-hospital and post-discharge settings in 13 elective cardiac surgery patients (5.2% enrolled from 252 screened). We found that room traffic continued during nighttime with ≥1 visit/h. Sound levels exceeded the recommended 45 dBA threshold (51.9 ± 3.3 vs. 48.3 ± 4.2 dBA during nighttime). Brightness dropped at night (89.9 ± 87.7 to 3.7 ± 9.8 lux), but bright light exposures occurred. Ambient room temperature lacked sleep-inducing diurnal variability. Behavioral-physiological rhythms were disrupted and phase-shifted during hospitalization. Time awake during night hours increased from 10.7 ± 7.9% preoperatively to 34.8 ± 29.1% in-hospital. Cognitive function scores decreased (26.8 ± 2.8 points preoperatively to 24.7 ± 3.9 points in-hospital) with 31% of patients developing transient mild impairment. These data will inform the design of a controlled trial seeking to modify circadian/diurnal disruptors to enhance patient outcomes. Clinicaltrials.gov NCT05828680, November 21, 2022.