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Sleep quality and circadian rhythm disruption in the intensive care unit: a review

Authors Boyko Y, Jennum P, Toft P

Received 13 September 2017

Accepted for publication 5 October 2017

Published 10 November 2017 Volume 2017:9 Pages 277—284


Checked for plagiarism Yes

Review by Single anonymous peer review

Peer reviewer comments 2

Editor who approved publication: Professor Steven A Shea

Yuliya Boyko,1 Poul Jennum,2 Palle Toft1

1Department of Anesthesia and Intensive Care Medicine, Odense University Hospital, Odense, Denmark, 2Department of Clinical Neurophysiology, Danish Center for Sleep Medicine, Rigshospitalet, Glostrup, Denmark

Abstract: Sleep and circadian rhythm are reported to be severely abnormal in critically ill patients. Disturbed sleep can lead to the development of delirium and, as a result, can be associated with prolonged stay in the intensive care unit (ICU) and increased mortality. The standard criterion method of sleep assessment, polysomnography (PSG), is complicated in critically ill patients due to the practical challenges and interpretation difficulties. Several PSG sleep studies in the ICU reported the absence of normal sleep characteristics in many critically ill patients, making the standard method of sleep scoring insufficient in this patient group. Watson et al proposed a modified classification for sleep scoring in critically ill patients. This classification has not yet been validated. Sleep disturbance in the ICU is a multifactorial problem. The ICU environment, mechanical ventilation, medication, as well as the critical illness itself have been reported as important sleep disturbing factors. Secretion of sleep hormone, melatonin, expressing circadian rhythmicity was found abolished or phase delayed in critically ill patients. Various interventions have been tested in several studies aiming to improve sleep quality and circadian rhythm in the ICU. The results of these studies were inconclusive due to using the sleep assessment methods other than PSG or the absence of a reliable sleep scoring tool for the analysis of the PSG findings in this patient population. Development of a valid sleep scoring classification is essential for further sleep research in critically ill patients.

Keywords: critically ill patients, sleep patterns, polysomnography, environmental factors, mechanical ventilation, sedation; melatonin

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