Atypical sleep in critically ill patients on mechanical ventilation is associated with increased mortality.
Sleep patterns in critically ill patients' polysomnographic sleep studies (PSG) are severely abnormal.


PURPOSE
We aimed to investigate the association of atypical sleep patterns, micro-sleep phenomena (sleep spindles and K-complexes) and rapid eye movement (REM) sleep with intensive care unit (ICU), in-hospital and 90-day mortality in conscious critically ill patients on mechanical ventilation.


METHOD
This was a prospective descriptive study. We analysed 52 PSGs recorded in conscious critically ill patients on mechanical ventilation. PSGs were scored according to standard classification when possible. Otherwise, modified classification proposed for scoring sleep in critically ill patients was used. The association of PSG findings with mortality was studied using logistic regression and Weibull model of survival analysis.


RESULTS
The presence of atypical sleep patterns in accordance with modified sleep scoring classification was associated with higher odds for ICU mortality (odds ratio 11.63; p = 0.03). The absence of K-complexes was associated with higher odds for ICU mortality (odds ratio 11.63; p = 0.03), while the absence of sleep spindles was associated with higher odds for in-hospital (odds ratio 7.80; p = 0.02) and 90-day mortality (odds ratio 5.51; p = 0.02). Loss of sleep spindles was associated with higher mortality risk with cutoff point 90 days (hazard ratio 3.87; p = 0.03).


CONCLUSIONS
The presence of atypical sleep and absence of normal PSG sleep characteristics in conscious critically ill patients on mechanical ventilation indicates involvement of sleep producing brain structures in the pathological process and is associated with poor outcome.
['Boyko|Yuliya|Y|http://orcid.org/0000-0001-7143-8462', 'Toft|Palle|P|', 'Ørding|Helle|H|', 'Lauridsen|Jørgen T|JT|', 'Nikolic|Miki|M|', 'Jennum|Poul|P|']
D000328:Adult D000368:Aged D000369:Aged, 80 and over D016292:Conscious Sedation D000078331:Correlation of Data D016638:Critical Illness D003718:Denmark D005260:Female D006801:Humans D007239:Infections D007362:Intensive Care Units D008297:Male D008875:Middle Aged D016017:Odds Ratio D017286:Polysomnography D011446:Prospective Studies D012121:Respiration, Artificial D012131:Respiratory Insufficiency D012307:Risk Factors D012893:Sleep Wake Disorders D012895:Sleep, REM
Atypical sleep Critically ill patients Sleep scoring classification Polysomnography