Factors influencing quality of sleep among non-mechanically ventilated patients in the Intensive Care Unit

Abstract

Aim

To investigate the self-reported quality of sleep of non-mechanically ventilated patients admitted to an ICU, and to identify barriers to sleep in this setting.

Method

Patients admitted to the ICU of Frankston Hospital over a two month period who had spent at least one night in the ICU, and had not received mechanical ventilation were surveyed as they were discharged from the ICU. This survey required patients to rate the quality of their sleep in the ICU and at home immediately prior to hospitalisation on a 10 cm visual analogue scale; and to identify perceived barriers to sleep in the ICU and at home prior to hospitalisation.

Results

56 respondents were surveyed during the study period. Median age was 74 years (range = 18–92 years); median ICU length of stay was 1 day (range = 1–7 days).

Overall, respondents rated their quality of sleep in ICU (median = 4.9/10) as significantly worse than at home immediately prior to ICU admission (median = 7.15/10; Z = −3.02, p < 0.002); however 44% of respondents rated their quality of sleep in ICU as better, or no worse, than at home immediately prior to hospitalisation. Sub-group analysis revealed that among patients with reduced quality of sleep (<5/10) prior to hospitalisation, 71.4% rated their quality of sleep in ICU as better, or no worse, than at home prior to hospitalisation, with no significant difference between sleep quality ratings in ICU and at home (p = 0.341).

Respondents identified the following as barriers to sleep in the ICU: noise levels overnight (53.6%); discomfort (33.9%); pain (32.1%); being awoken for procedures (32%); being attached to medical devices (28.6%); stress/anxiety (26.8%); and light levels (23.2%).

Conclusion

Pre-hospitalisation sleep quality appears to be an important influence on sleep in ICU. Many barriers to sleep in the ICU identified by respondents are potentially modifiable.

Introduction

Sleep has long been recognised as essential for good health, allowing for both physical and psychological restoration and recovery from illness. Poor quality sleep has been associated with impaired immune function and associated susceptibility to illness and infection, decreased energy levels, delirium, delays in recovery, and disturbed cognitive, respiratory, cardiac, and endocrine function.1, 2 Good-quality sleep is therefore an important part of recovery from critical illness.

Numerous studies have reported that patients admitted to ICU regularly experience reduced quality and duration of sleep with frequent awakenings and loss of circadian rhythm.1, 2, 3, 4, 5 The environment of the Intensive Care Unit (ICU) itself poses numerous barriers to sleep.2, 3, 6, 7 Critically ill patients admitted to the ICU are subject to disrupted day/night routine, high levels of noise (e.g. staff conversations and alarms) and light levels overnight, invasive and painful procedures, noxious smells, numerous physical restraints (such as monitor leads, catheters, and oxygen masks or mechanical ventilation), and stress, in addition to illness and pain associated with their health condition.1, 7, 8, 9

Research utilising self-report measures has consistently found that patients experience poor quality of sleep (QoS) and increased daytime sleepiness whilst in the ICU.1, 3, 7, 10 These findings have been largely attributed to the nature of the ICU environment and the numerous barriers posed to sleep by routine care in this setting.

Few studies have attempted to examine and account for the quality and patterns of patients’ sleep prior to ICU admission. Chronic illness and pain may predispose individuals to poor sleep prior to ICU admission, and inadequate or fragmented sleep may exacerbate the acute deterioration of an individual's health state, necessitating hospitalisation.3, 11 Bihari and colleagues³ found that QoS at home prior to ICU admission was a significant predictor of QoS in the ICU; however QoS at home only accounted for 6% of variability in reported sleep quality throughout ICU stay. This relationship is further called into question by Ehlers and colleagues,⁷ who found that 82% of ICU patients reported that they slept well or ‘very well’ at home, despite 71% reporting inadequate sleep in the ICU. It is therefore important to investigate whether individuals admitted to the ICU have poor baseline sleep quality preceding ICU admission, in order to better-account for the influence of the ICU environment on the quality of patients’ sleep.

This study aims to examine the self-reported QoS of non-mechanically ventilated patients admitted to the ICU of Frankston Hospital (Victoria, Australia), particularly in relation to their pre-hospitalisation QoS. This study also aims to examine the factors identified by patients as barriers to gaining sufficient sleep whilst in the ICU.