Fan Emily P, Abbott Sabra M, Reid Kathryn J, Zee Phyllis C, Maas Matthew B
Department of Neurology and the Center for Circadian and Sleep Medicine, Northwestern University, Chicago, IL, United States.
Department of Neurology and the Center for Circadian and Sleep Medicine, Northwestern University, Chicago, IL, United States.
J Crit Care. 2017 Aug;40:11-14. doi: 10.1016/j.jcrc.2017.03.002. Epub 2017 Mar 7.
We sought to characterize ambient light exposure in the intensive care unit (ICU) environment to identify patterns of light exposure relevant to circadian regulation.
A light monitor was affixed to subjects' bed at eye level in a modern intensive care unit and continuously recorded illuminescence for at least 24h per subject. Blood was sampled hourly and measured for plasma melatonin. Subjects underwent hourly vital sign and bedside neurologic assessments. Care protocols and the ICU environment were not modified for the study.
A total of 67,324 30-second epochs of light data were collected from 17 subjects. Light intensity peaked in the late morning, median 64.1 (interquartile range 19.7-138.7) lux. The 75th percentile of light intensity exceeded 100lx only between 9AM and noon, and never exceeded 150lx. There was no correlation between melatonin amplitude and daytime, nighttime or total light exposure (Spearman's correlation coefficients all <0.2 and p>0.5).
Patients' environmental light exposure in the intensive care unit is consistently low and follows a diurnal pattern. No effect of nighttime light exposure was observed on melatonin secretion. Inadequate daytime light exposure in the ICU may contribute to abnormal circadian rhythms.
我们试图描述重症监护病房（ICU）环境中的环境光照情况，以确定与昼夜节律调节相关的光照模式。
在一个现代化的重症监护病房中，将一个光照监测器固定在受试者眼睛水平高度的床头，每位受试者持续记录光照度至少24小时。每小时采集血液样本并检测血浆褪黑素水平。受试者每小时进行生命体征和床边神经学评估。本研究未对护理方案和ICU环境进行修改。
共从17名受试者收集了67324个30秒的光照数据时段。光照强度在上午晚些时候达到峰值，中位数为64.1（四分位间距19.7 - 138.7）勒克斯。光照强度的第75百分位数仅在上午9点至中午之间超过100勒克斯，且从未超过150勒克斯。褪黑素振幅与白天、夜间或总光照暴露之间无相关性（斯皮尔曼相关系数均<0.2且p>0.5）。
重症监护病房患者的环境光照持续较低且呈现昼夜模式。未观察到夜间光照暴露对褪黑素分泌有影响。重症监护病房白天光照不足可能导致昼夜节律异常。
