Sleep in Critically III Chemically Paralyzed Patients Requiring Mechanical Ventilation
Sleep deprivation is a well-documented problem among patients in the ICU and may impair physiologic and psychological well-being. Initial investigations using polysomnography reveal decreased total sleep time (TST), as well as abnormal sleep architecture with increased stage 1 and stage 2 non-rapid eye movement sleep, decreased slow wave sleep (SWS), and decreased rapid eye movement (REM) sleep. However, these studies are limited to only 8-h nighttime data collection and excluded patients receiving mechanical ventilation. add comment
Twenty-four-hour polysomnography in ICU patients receiving mechanical ventilation demonstrated inconsistent results in TST and sleep architecture. Cooper and coworkers report a subset of patients with > 50% delta activity and considered this to be “unidentifiable electrophysiologic sleep” consistent with encephalopathy or coma, although no specific source for encephalopathy could be determined. Gabor and colleagues, in contrast to prior ICU studies, determined REM sleep time (14.3%) to be normal.
The etiology of sleep disruption in critically ill patients requiring mechanical ventilation is multifactorial. Sleep deprivation can have significant consequences and has been shown to impair cognitive function, increase protein catabolism, decrease immune function, and alter respiratory mechanics that could negatively impact tolerance to and weaning from mechanical ventilation.
Neuromuscular blocking agents (NMBAs) are necessary at times to facilitate mechanical ventila-tion. Although anxiolytic medications are routinely administered, patients have reported feeling “buried alive,” have recollection of events, and complain of poor sleep while receiving mechanical ventilation and/or NMBAs. Previous sleep investigations have not included patients receiving NMBAs, and their effect on sleep patterns is unknown. Accurate and objective monitoring of sleep is necessary in patients receiving NMBAs in whom visual and behavioral evidence of their sleep state is lost. Additionally, sleep data are limited in the severely ill ICU patient population requiring mechanical ventilation,
We hypothesized that patients requiring NMBAs would have severely disrupted sleep architecture and would be oversedated due to the loss of visual evidence of sleep/wake state resulting in excessive delta activity. The aims of our study were as follows: (1) substantiate and add to the limited information on 24-h sleep patterns in critically ill patients receiving mechanical ventilation; (2) determine if NMBAs have an effect on sleep patterns; and (3) evaluate the effects of sedation dosage, severity of illness scores, and other clinical indexes on sleep architecture.
Category: Respiratory Symptoms
Tags: ICU, mechanical ventilation, polysomnography, sleep