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Critical Care Research and Practice
Volume 2017, Article ID 7010854, 8 pages
Research Article

Melatonin Secretion Pattern in Critically Ill Patients: A Pilot Descriptive Study

1Department of Anesthesia and Intensive Care Medicine, Odense University Hospital and Southern Danish University, Odense, Denmark
2Institute of Regional Health Service Research, University of Southern Denmark, Odense, Denmark
3Danish Center for Sleep Medicine, Department of Clinical Neurophysiology, Rigshospitalet, and Faculty of Health, University of Copenhagen, Copenhagen, Denmark
4Department of Anesthesia and Intensive Care Medicine, Vejle Hospital, Vejle, Denmark
5Faculty of Health, Southern Danish University, Odense, Denmark
6Danish Center for Sleep Medicine, Department of Clinical Neurophysiology, Rigshospitalet, Copenhagen, Denmark

Correspondence should be addressed to Yuliya Boyko; kd.dysr@okyob.ayiluy

Received 22 March 2017; Accepted 23 April 2017; Published 11 May 2017

Academic Editor: Robert Boots

Copyright © 2017 Yuliya Boyko et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


Critically ill patients have abnormal circadian and sleep homeostasis. This may be associated with higher morbidity and mortality. The aims of this pilot study were (1) to describe melatonin secretion in conscious critically ill mechanically ventilated patients and (2) to describe whether melatonin secretion and sleep patterns differed in these patients with and without remifentanil infusion. Eight patients were included. Blood-melatonin was taken every 4th hour, and polysomnography was carried out continually during a 48-hour period. American Academy of Sleep Medicine criteria were used for sleep scoring if sleep patterns were identified; otherwise, Watson’s classification was applied. As remifentanil was periodically administered during the study, its effect on melatonin and sleep was assessed. Melatonin secretion in these patients followed a phase-delayed diurnal curve. We did not observe any effect of remifentanil on melatonin secretion. We found that the risk of atypical sleep compared to normal sleep was significantly lower () under remifentanil infusion. Rapid Eye Movement (REM) sleep was only observed during the nonsedation period. We found preserved diurnal pattern of melatonin secretion in these patients. Remifentanil did not affect melatonin secretion but was associated with lower risk of atypical sleep pattern. REM sleep was only registered during the period of nonsedation.