Maya N. Elías is a postdoctoral research fellow, School of Nursing and Health Studies, University of Miami, Coral Gables, Florida.
Cindy L. Munro is dean and a professor, School of Nursing and Health Studies, University of Miami, Coral Gables, Florida.
Am J Crit Care. 2021 Mar 1;30(2):e40-e47. doi: 10.4037/ajcc2021221.
Sleep duration and proportion of daytime versus nighttime sleep may affect cognitive function in older patients in the transition out of the intensive care unit.
To explore the relationship between the daytime-to-nighttime sleep ratio and cognitive impairment in older intensive care unit survivors.
The study enrolled 30 older adults within 24 to 48 hours after intensive care unit discharge. All participants were functionally independent before admission and underwent mechanical ventilation in the intensive care unit. Actigraphy was used to estimate daytime (6 AM to 9:59 PM) and nighttime (10 PM to 5:59 AM) total sleep duration. Daytime-to-nighttime sleep ratios were calculated by dividing the proportion of daytime sleep by the proportion of nighttime sleep. The National Institutes of Health Toolbox Cognition Battery Dimensional Change Card Sort Test (DCCST) was used to assess cognition. Associations between sleep and cognition were explored using multivariate regression after adjusting for covariates.
The mean (SD) daytime sleep duration was 7.55 (4.30) hours (range, 0.16-14.21 hours), and the mean (SD) nighttime sleep duration was 4.99 (1.95) hours (range, 0.36-7.21 hours). The mean (SD) daytime-to-nighttime sleep ratio was 0.71 (0.30) (range, 0.03-1.10). Greater daytime sleep duration (β = -0.351, P = .008) and higher daytime-to-nighttime sleep ratios (β = -0.373, P = .008) were negatively associated with DCCST scores.
The daytime-to-nighttime sleep ratio was abnormally high in the study population, revealing an altered sleep/wake cycle. Higher daytime-to-nighttime sleep ratios were associated with worse cognition, suggesting that proportionally greater daytime sleep may predict cognitive impairment.
睡眠时长和白天与夜间睡眠时间的比例可能会影响从重症监护病房出院的老年患者的认知功能。
探究白天与夜间睡眠时间比例与重症监护病房老年幸存者认知障碍的关系。
该研究纳入了 30 名在重症监护病房出院后 24 至 48 小时内的老年人。所有参与者在入院前均能独立活动，并在重症监护病房接受机械通气。通过活动记录仪估计白天（6:00 AM 至 9:59 PM）和夜间（10:00 PM 至 5:59 AM）的总睡眠时间。白天与夜间睡眠时间比例通过白天睡眠时间除以夜间睡眠时间的比例计算得出。采用 NIH 工具包认知电池多维变化卡片分类测验（DCCST）评估认知功能。在调整协变量后，使用多元回归分析睡眠与认知之间的关联。
平均（SD）白天睡眠时间为 7.55（4.30）小时（范围：0.16-14.21 小时），平均（SD）夜间睡眠时间为 4.99（1.95）小时（范围：0.36-7.21 小时）。平均（SD）白天与夜间睡眠时间比例为 0.71（0.30）（范围：0.03-1.10）。白天睡眠时间较长（β=-0.351，P=0.008）和白天与夜间睡眠时间比例较高（β=-0.373，P=0.008）与 DCCST 评分呈负相关。
研究人群的白天与夜间睡眠时间比例异常高，表明睡眠/觉醒周期发生改变。较高的白天与夜间睡眠时间比例与认知障碍相关，提示白天睡眠时间比例增加可能预示认知障碍。
