Page 257 - Hall et al (2015) Principles of Critical Care-McGraw-Hill

CHAPTER 23: Sleep 161

identifiable sleep stages with associated transitions, and by a variety of may benefit from eyeshades and earplugs, although care should be taken
other characteristic behavioral and polysomnographic features. to avoid causing distress to patients who might be confused.
Many of these features are not consistently identified in sedated Perform discretionary patient care activities during the daytime
patients. Cooper et al studied 20 critically ill patients receiving mechani- hours: In most ICUs, certain activities are performed during the night
cal ventilation and continuous intravenous sedation. None of their only because it is more difficult to accomplish them during the day,
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subjects exhibited normal sleep, and only eight demonstrated electro- when the care demands are greater. Baths are one example. In order to
physiologically identifiable sleep. The sleep recordings of the remaining routinize the performance of baths outside of prime resting time, it may
patients exhibited a variety of abnormalities, including the presence of be necessary to make staffing changes. Other examples of potentially
pathological wakefulness and delta/theta coma. Severe reductions in modifiable care activities include chest radiography and phlebotomy.
REM sleep have been noted by other investigators as well. 27,47 Indeed, the Consider designating a “quiet time” during the afternoon: Some
polysomnographic recordings that are obtained in this patient popula- patients may benefit from a brief nap during the early to midafternoon.
tion belie conventional sleep scoring. This was convincingly shown by ICUs that have adopted this policy have attempted to publicize this activ-
Ambrogio et al in a study that showed the remarkably poor reproduc- ity by posting notices on patient room doors and throughout the ICU.
ibility of conventional visual sleep scoring in this patient population, For patients receiving continuous intravenous sedation, perform a
except where the identification of REM sleep was concerned. It is clear daily sedative interruption: The benefits of this approach have already
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from this study and from others that a new approach to visual scoring been demonstrated. Where sleep and circadian rhythmicity are con-
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is needed for this setting. Quantitative EEG methodologies, including cerned, daily sedative interruption—ideally during the morning—may
spectral analysis, possess the advantage of seemingly perfect reproduc- help strengthen circadian rhythmicity by promoting awakening and
ibility. However, these methods are also highly sensitive to artifact and light exposure during the daytime.
are subject to potential bias in the removal of artifact. In addition, the For patients receiving mechanical ventilation, consider minimizing
biologic significance in this patient population of the derived parameters the use of pressure support ventilation during the nighttime if pos-
is at present uncertain. sible: While in certain situations the use of pressure support ventilation
Basic investigations suggest that sedation possesses at least some during the nighttime may be preferable, the greater sleep fragmentation
restorative properties similar to sleep. 49,50 Given that sedation and sleep engendered by this mode makes it a less attractive mode during the
exhibit overlapping neurophysiologic processes, this is unsurprising. It is nighttime if there are no other reasons to prefer it over assist-control
not known, however, whether patients receiving continuous intravenous ventilation or proportional assist ventilation.
sedation experience the whole complement of benefits conferred by normal
sleep. Indeed, recent studies performed in more controlled settings high-
light certain differences between sleep and sedation and/or anesthesia. 51,52
and underscore the likelihood that not all homeostatic needs are met KEY REFERENCES
by sedation. It also appears likely that sedation has the capacity to dra- • Ambrogio C, Koebnick J, Quan SF, Ranieri VM, Parthasarathy S.
matically affect circadian rhythmicity, either through the dispersion of Assessment of sleep in ventilator-supported critically ill patients.
sleep-like activity over a 24-hour period, or by insulating the patient Sleep. 2008;31:1559-1568.
from environmental cues via eye closure and decreased responsiveness
to other external stimuli. • Bank S, Dinges DF. Behavioral and physiological consequences of
sleep restriction. J Clin Sleep Med. 2007;3(5):519-528.
■ SLEEP AFTER INTENSIVE CARE • Cooper AB, Thornley KS, Young GB, Slutsky AS, Stewart TE,
The sleep of survivors of critical illness has not been systematically Hanly PJ. Sleep in critically ill patients requiring mechanical ven-
tilation. Chest. 2000;117:809-818.
investigated. Patients transferred to step-down units continue to exhibit
a wide range of sleep abnormalities that do not appear to be predomi- • Drouot X, Roche-Campo F, Thille AW, et al. A new classification for
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nantly to mechanical ventilation. Although unproven, it seems likely sleep analysis in critically ill patients. Sleep Med. 2012;13(1):7-14.
that sleep abnormalities persist in many such patients long after hospital • Fanfulla F, Ceriana P, D’ArtavillaLupo N, et al. Sleep disturbances
discharge, and that ongoing sleep disruption may impair recovery from in patients admitted to a step-down unit after ICU discharge: the
critical illness by negatively impacting mood and motivation, metabo- role of mechanical ventilation. Sleep. 2011;34(3):355-362.
lism, the immune response, and overall vitality. It is also possible that • Freedman NS, Gazendam J, Levan L Pack AI, Schwab RJ. Abnormal
disrupted sleep during and after intensive care may partly mediate the sleep/wake cycles and the effect of environmental noise on sleep
long-term neurocognitive outcomes of critical illness. 54-56 Ultimately, the disruption in the intensive care unit. Am J Respir Crit Care Med.
systematic study of sleep and circadian rhythmicity after intensive care 2001;163:451-457.
may prove as important as its study in the ICU. • Gehlbach BK, Chapotot F, Leproult R, et al. Temporal disorga-
■ PROMOTING SLEEP IN THE ICU nization of circadian rhythmicity and sleep-wake regulation in

There are currently no studies showing that improving sleep quality mechanically ventilated patients receiving continuous intravenous
sedation. 2012;35(8):1105-1114.
improves critical care outcomes. Until such evidence is available, there • Goel N, Rao H, Durmer JS, Dinges DF. Neurocognitive conse-
are a variety of practices that seem reasonable to implement. quences of sleep deprivation. Semin Neurol. 2009;29:320-339.
Increase light exposure during the day, particularly during the
morning: Daytime light exposure can increase alertness while poten- • Haimovich B, Calvano J, Haimovich AD, et al. In vivo endotoxin
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tially normalizing circadian timing. Daytime hours should be set and synchronizes and suppresses clock gene expression in human
artificial lights and blinds adjusted accordingly. The use of supplemental peripheral blood leukocytes. Crit Care Med. 2010;38(3):751-758.
bright lights similar to those used in ambulatory patients with disorders • Kamdar BB, Needham DM, Collop NA. Sleep deprivation in
of circadian rhythmicity has not been investigated to date. critical illness: its role in physical and psychological recovery.
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Minimize light and noise exposure during the night: The television J Intensive Care Med. 2012;27(2):97-111.
and radio should be turned off. Blinds should be lowered and artificial • Mundigler G, Delle-Karth G, Koreny M, et al. Impaired circadian
lights lowered to the extent allowed for safe patient care in order to rhythm melatonin secretion in sedated critically ill patients with
promote sleep and to avoid the potential adverse effects of evening light severe sepsis. Crit Care Med. 2002;30:536-540.
exposure on circadian rhythmicity and sleep quality. Some patients
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