Which is the most effective nursing intervention to promote sleep that is appropriate for a patient in any situation?

Cochrane Database Syst Rev. 2015 Oct; 2015(10): CD008808.

Monitoring Editor: Rong‐Fang Hu, Xiao‐Ying Jiang,

Fujian Medical University, School of Nursing, FujianChina

The First Affiliated Hospital of Fujian Medical University, Department of Haematology and Rheumatology, 20 Chazhong Road, FuzhouFujian ProvinceChina, 350005

The First Affiliated Hospital of Fujian Medical University, Department of Hematology and Rheumatology, Chating, FuzhouFujian ProvinceChina, 350005

The Second Affiliated Hospital of Fujian Medical University, Department of Respiratory Medicine, Chating, QuanzhouFujian ProvinceChina, 362000

Fujian Medical University, School of Public Health, Chating, FuzhouFujian ProvinceChina, 350005

Fujian Provincial Hospital, Department of Neuro‐medicine, DongjieChina, 350000

Lancaster Medical School, LancasterUK, LA1 4YG

Fujian Medical University, School of Nursing, FuzhouChina

Abstract

Background

Adults in intensive care units (ICUs) often suffer from a lack of sleep or frequent sleep disruptions. Non‐pharmacological interventions can improve the duration and quality of sleep and decrease the risk of sleep disturbance, delirium, post‐traumatic stress disorder (PTSD), and the length of stay in the ICU. However, there is no clear evidence of the effectiveness and harms of different non‐pharmacological interventions for sleep promotion in adults admitted to the ICU.

Objectives

To assess the efficacy of non‐pharmacological interventions for sleep promotion in critically ill adults in the ICU.

To establish whether non‐pharmacological interventions are safe and clinically effective in improving sleep quality and reducing length of ICU stay in critically ill adults.

To establish whether non‐pharmacological interventions are cost effective.

Search methods

We searched the Cochrane Central Register of Controlled Trials (CENTRAL, 2014, Issue 6), MEDLINE (OVID, 1950 to June 2014), EMBASE (1966 to June 2014), CINAHL (Cumulative Index to Nursing and Allied Health Literature, 1982 to June 2014), Institute for Scientific Information (ISI) Web of Science (1956 to June 2014), CAM on PubMed (1966 to June 2014), Alt HealthWatch (1997 to June 2014), PsycINFO (1967 to June 2014), the China Biological Medicine Database (CBM‐disc, 1979 to June 2014), and China National Knowledge Infrastructure (CNKI Database, 1999 to June 2014). We also searched the following repositories and registries to June 2014: ProQuest Dissertations & Theses Global, the US National Institutes of Health Ongoing Trials Register (www.clinicaltrials.gov), the metaRegister of Controlled Trials (ISRCTN Register) (www.controlled‐trials.com), the Chinese Clinical Trial Registry (www.chictr.org.cn), the Clinical Trials Registry‐India (www.ctri.nic.in), the Grey Literature Report from the New York Academy of Medicine Library (www.greylit.org), OpenGrey (www.opengrey.eu), and the World Health Organization International Clinical Trials Registry platform (www.who.int/trialsearch). We handsearched critical care journals and reference lists and contacted relevant experts to identify relevant unpublished data.

Selection criteria

We included all randomized controlled trials (RCT) and quasi‐RCTs that evaluated the effects of non‐pharmacological interventions for sleep promotion in critically ill adults (aged 18 years and older) during admission to critical care units or ICUs.

Data collection and analysis

Two authors independently screened the search results and assessed the risk of bias in selected trials. One author extracted the data and a second checked the data for accuracy and completeness. Where possible, we combined results in meta‐analyses using mean differences and standardized mean differences for continuous outcomes and risk ratios for dichotomous outcomes. We used post‐test scores in this review.

Main results

We included 30 trials, with a total of 1569 participants, in this review. We included trials of ventilator mode or type, earplugs or eye masks or both, massage, relaxation interventions, foot baths, music interventions, nursing interventions, valerian acupressure, aromatherapy, and sound masking. Outcomes included objective sleep outcomes, subjective sleep quality and quantity, risk of delirium, participant satisfaction, length of ICU stay, and adverse events. Clinical heterogeneity (e.g., participant population, outcomes measured) and research design limited quantitative synthesis, and only a small number of studies were available for most interventions. The quality of the evidence for an effect of non‐pharmacological interventions on any of the outcomes examined was generally low or very low. Only three trials, all of earplugs or eye masks or both, provided data suitable for two separate meta‐analyses. These meta‐analyses, each of two studies, showed a lower incidence of delirium during ICU stay (risk ratio 0.55, 95% confidence interval (CI) 0.38 to 0.80, P value = 0.002, two studies, 177 participants) and a positive effect of earplugs or eye masks or both on total sleep time (mean difference 2.19 hours, 95% CI 0.41 to 3.96, P value = 0.02, two studies, 116 participants); we rated the quality of the evidence for both of these results as low.

There was also some low quality evidence that music (350 participants; four studies) may improve subjective sleep quality and quantity, but we could not pool the data. Similarly, there was some evidence that relaxation techniques, foot massage, acupressure, nursing or social intervention, and sound masking can provide small improvements in various subjective measures of sleep quality and quantity, but the quality of the evidence was low. The effects of non‐pharmacological interventions on objective sleep outcomes were inconsistent across 16 studies (we rated the quality of the evidence as very low): the majority of studies relating to the use of earplugs and eye masks found no benefit; results from six trials of ventilator modes suggested that certain ventilator settings might offer benefits over others, although the results of the individual trials did not always agree with each other. Only one study measured length of stay in the ICU and found no significant effect of earplugs plus eye masks. No studies examined the effect of any non‐pharmacological intervention on mortality, risk of post‐traumatic stress disorder, or cost‐effectiveness; the included studies did not clearly report adverse effects, although there was very low quality evidence that ventilator mode influenced the incidence of central apnoeas and patient‐ventilator asynchronies.

Authors' conclusions

The quality of existing evidence relating to the use of non‐pharmacological interventions for promoting sleep in adults in the ICU was low or very low. We found some evidence that the use of earplugs or eye masks or both may have beneficial effects on sleep and the incidence of delirium in this population, although the quality of the evidence was low. Further high‐quality research is needed to strengthen the evidence base.

Plain language summary

Non‐drug treatments for promoting sleep in adults in the intensive care unit

Review question

We reviewed the evidence on non‐pharmacological interventions (i.e. non‐drug treatments) for improving sleep in critically ill adults.

Background

Sleep is essential to enable adults in the intensive care unit (ICU) to recover from their illnesses. However, adults in the ICU often suffer from frequently disturbed sleep or a lack of sleep. The reasons for sleep disruption may include the underlying illness, uncomfortable therapy, psychological stress, or the ICU environment itself.

Interventions for sleep promotion include pharmacological treatments and non‐pharmacological interventions. Medications may produce side effects, such as a reduced ability to think clearly and negative effects on breathing, and they can also interfere with normal sleep patterns and lead to a risk of tolerance or drug dependency . Therefore, non‐pharmacological interventions, such as noise reduction, music therapy, alternative and complementary therapies, and social support, have been sought and are recommended for improving sleep in critically ill adults.

Search date

The evidence is current to June 2014.

Study characteristics

We found 30 trials, with a total of 1569 participants, and the interventions included changes to ventilator type and settings, earplugs and eye masks, relaxation therapy, sleep‐inducing music, massage, foot baths, aromatherapy, valerian acupressure, sound masking, and changing the visiting times of family members. We assessed the effects of these interventions on sleep outcomes (e.g., quality and amount of sleep), length of stay in the ICU, the occurrence of delirium, other adverse events, and death.

Key results and quality of evidence

Overall, the quality of the evidence for an effect of the interventions on any of the outcomes was low or very low. Normally, we would try to pool findings from similar trials of each intervention, but this was difficult because the design of the trials varied greatly. We were able to combine the results from three trials of earplugs and eye masks and found that their use increased the number of hours slept and prevented delirium in adults in the ICU. However, we cannot be certain about these findings because of problems with how the trials were carried out.

There was also some low quality evidence from four studies that music may improve subjective sleep quality and quantity, but we could not pool the data. Similarly, a low number of studies found that relaxation techniques, foot massage, acupressure, nursing or social intervention, and sound masking can provide small improvements in participant‐reported or nurse‐assessed sleep quality and quantity, but the quality of the evidence was low. The effects of the interventions on objective sleep outcomes (e.g., sleep measured by a machine) varied: the majority of studies that looked at the use of earplugs and eye masks found no benefit, and although the results from six trials of ventilator modes suggested that certain ventilator settings might offer benefits over others, the results of the individual trials did not always agree with each other. Only one study measured length of stay in the ICU and found no significant effect of earplugs plus eye masks. None of the included studies looked at economic outcomes, risk of post‐traumatic stress disorder, or deaths. The trials did not clearly report adverse effects, although there was very low quality evidence that ventilator mode might influence certain adverse effects that can happen when people are on a ventilator. In summary, further well‐designed and conducted research is needed to strengthen the evidence for the use of these interventions for improving sleep in critically ill adults.

Summary of findings

Background

Description of the condition

Sleep is a basic need for human survival and is essential for the recovery of critically ill adults. Normal human sleep is generally categorized as two states: non‐rapid eye movement (NREM) and rapid eye movement (REM), which alternate cyclically across a sleep episode. The American Academy of Sleep Medicine Scoring Manual (SiIber 2007) further subdivides NREM sleep into stages one to three. Sleep begins in NREM stage one (N1) and progresses through the deeper NREM stage two (N2) to NREM stage three (N3), which is also called delta sleep or slow‐wave sleep (SWS). A progressive increase in the threshold required for arousal (e.g., by noise) accompanies the progression of sleep from stage N1 through to stage N3. NREM sleep normally cycles with REM sleep approximately every 90 minutes. Normally, REM sleep accounts for about 25% of sleep time, and adults spend up to 50% of the night in stage N2 sleep.

Adults in intensive care units (ICUs) often suffer from a lack of sleep or frequent sleep disruptions (Gabor 2003; Meyer 1994). Both subjective and objective studies have demonstrated significant sleep disruption in critically ill patients (Freedman 1999; Freedman 2001; Friese 2007; Gabor 2001; Parthasarathy 2004; Simini 1999). In one study, as many as 38% of ICU patients experienced difficulty in falling asleep, and 61% reported shorter periods of sleep than usual (Orwelius 2008). Several studies using polysomnography (PSG) have consistently demonstrated that the sleep of ICU patients is characterized by sleep fragmentation, poor sleep efficiency, an increase in light sleep, and a decrease in both REM sleep and SWS (Cooper 2000; Freedman 2001; Friese 2007). Moreover, about 50% of sleep occurs during the day in ICU patients (Cooper 2000; Freedman 2001; Gabor 2003; Hardin 2006).

PSG represents the gold standard for techniques used to monitor sleep and is the only method to identify the individual sleep stages. However, many centres lack the facilities required for PSG (in terms of equipment and staff). Therefore, some studies (especially those performed in critical care units) have adopted other techniques for measuring sleep, such as actigraphy, Bispectral Index (BIS) monitoring, and nurse/patient assessment (Le Guen 2014; Jaber 2007). An ActiGraph is a small wristwatch device that can monitor whether a patient is asleep or awake based on the levels of patient wrist motor activity. ActiGraphs have been used in studies of sleep and circadian rhythms in ICU patients. However, actigraphy does not provide any information regarding either the stage or quality of sleep and tends to overestimate total sleep time compared with PSG and BIS. BIS is calculated from multiple analyses of the raw electroencephalography (EEG) waveform that is capable of detecting sleep, but the overlap of BIS values between given sleep stages currently prevents its use as a depth‐of‐sleep monitor (Nieuwenhuijs 2006). Furthermore, BIS values potentially provide an inaccurate indication of patients' sleep characteristics when patients have neurological abnormalities. ICU studies have often used subjective measurements of sleep: several visual analogue scales (VAS), such as the Verran/Snyder‐Halpern Sleep Scale (VSH) and the Richardson‐Campbell Sleep Questionnaire (RCSQ), have been developed and used to assess patients' sleep perception. The RCSQ score accounted for approximately 33% of the variance in the PSG indicator Sleep Efficiency Index (SEI) in one critical care group (Richards 2000). However, a problem with VAS scales is that patients may be incapable of completing the questionnaire; one study excluded half of the recruited participants because of unconsciousness or delirium (Frisk 2003).

The reasons for sleep disruption are multifactorial and include underlying illness, uncomfortable therapy, psychological stress, age‐related changes in sleep patterns, pain, mechanical ventilation, and the ICU environment (Drouot 2008; Friese 2008; Weinhouse 2006; Weinhouse 2009). Environmental stimuli are thought to be important factors. Light, noise, patient‐care activities, and physician interventions all contribute to sleep deprivation; noise and patient‐care activities are thought to account for approximately 30% of observed sleep disruption (Gabor 2003). Continuous exposure to light can also disrupt the patient's naturally occurring circadian rhythms (Czeisler 1986).

There are several adverse consequences of sleep disruption, which may include an impaired immune function (Benca 1997), reduced inspiratory muscle endurance (Chen 1989), an altered weaning process (Pandharipande 2006), a degeneration in the quality of life (Dignani 2015), and prolonged neurocognitive dysfunction (O'Donoghue 2012). Importantly, these adverse consequences may be associated with ICU delirium and severe morbidity (Eddleston 2000; Novaes 1999; Pun 2007; Weinhouse 2006).

Interventions for sleep promotion involve both pharmacological treatment and non‐pharmacological interventions. Generally, pharmacological therapies are used for the treatment of sleep disturbances (Abad 2015). Pharmacological agents that induce sleep provide sedation and analgesia and are commonly used in the ICU setting. However, pharmacological interventions have potential side effects, including impaired cognitive function, risk of tolerance or dependency, depressed ventilation, and adversely affected normal sleep physiology (Mistraletti 2008). For example, benzodiazepines, opiates, or barbiturates disrupt normal sleep patterns and decrease REM activity and stage 3 sleep (Achermann 1987; Cronin 2001), whereas propofol leads to slow‐wave activity that mimics slow‐wave sleep and modifies circadian rhythms (Ozone 2000). Therefore, sedation in the ICU is both a cause and a potential treatment for sleep disruption in ICU patients (Weinhouse 2009). Additionally, induction of sleep by drugs is contraindicated in certain patient groups, such as non‐ventilated patients suffering from hypercapnic lung disease (Shilo 1999). Therefore, non‐pharmacological interventions have been sought, and a multifaceted approach is recommended to improve the sleep of critically ill patients (Jacobi 2002). In general, the efficacy of non‐pharmacological interventions for improving sleep has been considered to be less than pharmacological methods while having no risk of drug‐related tolerance or dependency (Hauri 1997; McClusky 1991).

Description of the intervention

A wide range of non‐pharmacological interventions have been used to improve sleep in ICU patients. These can be broadly categorized as follows: psychological (cognitive or behavioural) interventions, complementary therapies (e.g., music therapy, aromatherapy, massage, guided imagery, acupressure), environmental interventions (e.g., synchronization of ICU activities with daylight, noise reduction), social interventions (e.g., family support), and equipment modification (e.g., optimizing ventilator modes or ventilator types). Cognitive behavioural therapy (CBT) has been used to treat insomnia in the ambulant setting by changing poor sleep habits and prompting sleep hygiene practices (Gałuszko‐Węgielnik 2012). A meta‐analysis of 224 participants (aged > 60 years) who experienced insomnia in an ambulant setting indicated a mild effect of CBT for sleep problems and was best used for sleep maintenance insomnia (Montgomery 2003).

How the intervention might work

Complementary therapies, such as massage, music therapy, therapeutic touch, aromatherapy, relaxation, and mental imaginary, seem to comfort and reduce levels of stress and anxiety in critically ill patients, which in turn is likely to lead to improved sleep (Richards 2003). A combination of relaxation and imagery may be effective in improving the sleep of the critically ill adult (Richards 2003). Environmental interventions, such as reducing noise, controlling lighting, playing white noise, and adequate uninterrupted time for sleep, are safe and logical interventions to help patients sleep (Richards 2003). Several studies found that the use of earplugs and eye masks as methods of noise reduction and light control improved sleep quality (Koo 2008; Richardson 2007; Scotto 2009). Optimising modes of mechanical ventilation may also facilitate sleep, as some modes have been found to cause less arousals and awakenings per hour (Cabello 2008; Friese 2008; Parthasarathy 2004). However, the use of such non‐pharmacological interventions in critical care needs to take account of environmental and patient considerations. Interventions must be easy to implement (i.e., practical) and must not harm or diminish patient safety.

Why it is important to do this review

Several systematic reviews have highlighted benefits of non‐pharmacological interventions for improving sleep in different patient populations. Previous systematic reviews have assessed the efficacy of valerian and exogenous melatonin for improving sleep (Bent 2006; Buscemi 2005). Similarly, previous Cochrane reviews have examined the effects of bright light therapy, cognitive behavioural therapy, and acupuncture in improving sleep quality in patients with insomnia or elderly people (Cheuk 2012; Montgomery 2002; Montgomery 2003). However, there remains little clear evidence of the effectiveness of non‐pharmacological interventions for improving sleep quality in critically ill patients residing in critical care units. An earlier systematic review examined the effects of massage on relaxation, comfort, and sleep in acute and critical care settings and concluded that the existing clinical data at that time were insufficient and further studies were required (Richards 2000a). A subsequent review of complementary and alternative therapies to promote sleep in critically ill patients concluded that techniques to promote sleep through muscle relaxation might be difficult for critically ill patients because of the need for patients to be conscious to receive the therapy. The review also reported that interventions such as music therapy, environmental interventions, therapeutic touch, and relaxing massage appeared to be safe but that further randomized controlled trials were required to assess efficacy (Richards 2003). Therefore, it was important to perform this review, which examined recent studies, particularly as there remains little guidance on the potential efficacy and harms of these interventions for adult patients in the critical care unit.

Objectives

To assess the efficacy of non‐pharmacological interventions (Appendix 1) for sleep promotion in critically ill adult patients in the ICU.

To establish whether non‐pharmacological interventions are safe and clinically effective in improving sleep quality and reducing length of ICU stay in critically ill adults.

To establish whether non‐pharmacological interventions are cost effective.

Methods

Criteria for considering studies for this review

Types of studies

We included randomized controlled trials (RCTs) and quasi‐RCTs that evaluated the effects of non‐pharmacological interventions for sleep promotion in critical care units (CCU) or intensive care units (ICUs) for critically ill adult participants (aged 18 years and older).

We included all studies, published or unpublished, in any language.

Types of participants

Critically ill adult patients with stable haemodynamic status who were admitted to ICUs or critical care units and had a length of stay of more than 24 hours. We included studies of surgical or non‐surgical patients with or without mechanical ventilation. We imposed no restrictions on gender or ethnicity. We excluded studies enrolling participants who were diagnosed with obstructive sleep apnoea or dementia or those who were terminally ill or required palliative care.

Types of interventions

We included any non‐pharmacological intervention for improving sleep, such as those that examined one or a combination of interventions, and compared them with different non‐pharmacological interventions, pharmacological interventions (e.g., sedation), or standard care (e.g., routine nursing care).

We included the following types of non‐pharmacological interventions:

• psychological (cognitive or behavioural) interventions, such as music therapy, back massage, muscle relaxation, imagery, and therapeutic touch;

• environmental interventions, such as noise reduction, lighting control, and synchronization of ICU activities with daylight;

• social support interventions;

• equipment modification, including mechanical ventilation;

• complementary and alternative therapies: aromatherapy, herbs, acupuncture; and

• physical therapy modalities.

Types of outcome measures

Primary outcomes

• Changes in objective sleep variables (as measured by polysomnography, ActiGraph, or Bispectral Index), including Sleep Efficiency Index (SEI), rapid eye movement (REM) sleep time, REM sleep latency, and sleep fragmentation index.

• Length of ICU stay.

• Mortality.

Secondary outcomes

• Any adverse reactions or events.

• Risk of delirium during ICU stay.

• Changes in subjective sleep quality or quantity, measured by participant report or medical or nursing observation.

• Risk of post‐traumatic stress disorder (PTSD) once discharged from hospital.

• Participant satisfaction (as reported by the study authors).

• Economic outcomes.

Search methods for identification of studies

Electronic searches

We searched the Cochrane Central Register of Controlled Trials (CENTRAL, 2014, Issue 6), 2014, Issue 6) (Appendix 2), MEDLINE (OVID, 1950 to June 2014) (Appendix 3), EMBASE (1966 to June 2014), CINAHL (Cumulative Index to Nursing and Allied Health Literature, 1982 to June 2014), Institute for Scientific Information (ISI) Web of Science (1956 to June 2014) (Appendix 4) , CAM on PubMed (1966 to June 2014), Alt HealthWatch (1997 to June 2014), PsycINFO (1967 to June 2014), the China Biological Medicine Database (CBM‐disc, 1979 to June 2014), and China National Knowledge Infrastructure (CNKI Database, 1999 to June 2014).

We searched for relevant ongoing trials up to June 2014 using the following websites.

• The World Health Organization International Clinical Trials Registry platform (WHO ICTRP) (www.who.int/trialsearch) ‐ four WHO ICTRP Primary Registers.

• Chinese Clinical Trial Registry (www.chictr.org.cn).

• The metaRegister of Controlled Trials (ISRCTN Register) (www.controlled‐trials.com).

• The US National Institutes of Health Ongoing Trials Register (www.clinicaltrials.gov).

• Clinical Trials Registry‐India (www.ctri.nic.in).

We searched for grey literature using the following websites.

• OpenGrey (www.opengrey.eu).

• Grey Literature Report from the New York Academy of Medicine Library (www.greylit.org).

• ProQuest Dissertations & Theses Global (www.search.proquest.com).

We modified the MEDLINE search strategy to search the other databases (Appendix 3).

Searching other resources

We handsearched appropriate journals and abstracts of relevant conference proceedings. We searched the reference lists of all retrieved articles. We did not limit the search by language or publication status.

We handsearched the following journals:

• Critical Care Medicine (1995 to May 2014);

• Critical Care (1997 to May 2014);

• Journal of Critical Care (1995 to May 2014); and

• American Journal of Respiratory and Critical Care Medicine (1995 to May 2014).

Data collection and analysis

Selection of studies

Two authors (HRF, CXY) independently examined the titles and abstracts identified from the search. We retrieved and evaluated the full text of potentially relevant studies. Two authors (HRF, ZZY) independently assessed their eligibility according to our inclusion and exclusion criteria, resolving any disagreements by discussion. A third author (CJM) settled any disagreements. Where appropriate, we corresponded with study authors by telephone or by email to clarify study eligibility. We recorded reasons for study exclusion in the 'Characteristics of excluded studies' tables.

Data extraction and management

Two authors (HRF, XHN) independently extracted data using a tool developed by the authors (Appendix 5). We resolved any disagreements by discussion with a third author (CJM). Two review authors entered the data into Review Manager software (RevMan 5.3), and a third author (JXY) checked the data.

Assessment of risk of bias in included studies

Two authors (HRF, LYP) independently assessed the quality of all included trials as described in the Cochrane Handbook for Systematic Reviews of Interventions (Higgins 2011). We assessed the methodological quality of all trials on the basis of the following six domains:

• random sequence generation;

• allocation concealment;

• blinding of participants, personnel, and outcome assessors;

• incomplete outcome data;

• selective reporting; and

• other sources of validity.

Measures of treatment effect

We calculated mean differences (MDs) with 95% confidence intervals (CI) for continuous data and standardized mean differences (SMDs) for outcome measures using results from different scales. Where possible, we obtained standard deviations from standard errors and confidence intervals. We analysed longer ordinal scales as continuous data. We combined adjacent categories together and made them into dichotomous data for trichotomous‐type outcomes. Where trichotomous‐type outcomes were summarized using methods for dichotomous data, we used risk ratios (RR) with 95% CIs to describe the intervention effect. We estimated heterogeneity using the I² statistic (Higgins 2011). In the case of significant clinical heterogeneity, we did not pool results.

Unit of analysis issues

We included both parallel and cross‐over randomized controlled trials. The participants in each intervention arm were the unit of analysis in a single parallel group design. According to the Cochrane Handbook for Systematic Reviews of Interventions (Higgins 2011), the recommended method for including multiple groups from one study is to combine all relevant experimental intervention groups from the study into a single group and combine all relevant control intervention groups into a single control group. Although we found an orphan study with more than a two‐arm parallel intervention group and some cross‐over trials with more than two intervention groups in this review, we could not include them in a meta‐analysis. Considering the presence of carry‐over, we had planned to analyse the data from only the first period in cross‐over RCTs. However, only two cross‐over RCTs reported data from the first period and the cross‐over period, whereas the remaining studies only reported the whole period data. Thus, we took the decision to exclude cross‐over studies from the meta‐analyses.

Dealing with missing data

Whenever possible, we contacted the trial authors to request missing data. We calculated missing statistics (such as standard deviations or correlation coefficients) from other statistics, such as the standard error or confidence intervals.

Assessment of heterogeneity

We firstly explored clinical heterogeneity by assessing the clinical and methodological characteristics of the included studies (for example, trial design, participant characteristics, intervention, or outcome measurement). If we pooled data from multiple studies, we formally assessed heterogeneity using the I² statistic (Higgins 2011) and by visual inspection of the forest plots. We considered a Chi² statistic with a P value < 0.10 or an inconsistency between studies (I² statistic) greater than 50% as evidence of relevant heterogeneity.

Assessment of reporting biases

We assessed the scope for reporting bias by the absence of primary outcomes and by less detailed reporting of non‐significant outcomes. Due to the small number of studies included in each category, we did not perform funnel plots for publication bias.

Data synthesis

We anticipated that studies would use different scales to measure the same outcomes. We calculated standardized mean differences (SMDs) from different scales. We made the following intervention comparisons using meta‐analyses: use of earplugs or eye masks or both versus no use of earplugs or eye masks. We had planned to include the following additional treatment comparisons, but there were insufficient trials to do so, or the available trials had important clinical heterogeneity among them: acupressure versus other interventions or placebo, aromatherapy versus other interventions or placebo, back massage versus other interventions or placebo, foot baths versus other interventions or placebo, relaxation and imagery versus other interventions or placebo, foot massage versus other interventions or placebo, using sound masking versus other interventions or placebo, and social support intervention versus other interventions or placebo. Therefore, we included trials comparing these interventions with other therapies or placebo in the narrative but not the meta‐analysis of this review.

Subgroup analysis and investigation of heterogeneity

We had planned to explore the following subgroups:

• age;

• sex;

• interventions (different methods, different duration, or difference frequency); and

• trial quality (e.g., RCT and quasi‐RCT).

However, since we only pooled two studies for each meta‐analysis in this review, we did not perform subgroup analyses (see Differences between protocol and review).

Sensitivity analysis

We did not perform sensitivity analyses due to the small number of studies included in each group (see Differences between protocol and review).

'Summary of findings' tables

We used the principles of the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach (Guyatt 2008) to assess the quality of the body of evidence associated with specific outcomes. Because of the number of interventions considered, the heterogeneity between studies, and the lack of meta‐analyses, we provided a narrative summary of findings: Table 1.

Summary of findings for the main comparison

Non‐pharmacological interventions for sleep promotion in ICU patients ‐ narrative summary

Results

Description of studies

Please see the 'Characteristics of included studies' tables; the 'Characteristics of excluded studies' tables; the 'Characteristics of studies awaiting classification' tables; and the 'Characteristics of ongoing studies' tables.

Results of the search

Please see Figure 1.

Study flow diagram. CBM = China Biological Medicine Database; CENTRAL = Cochrane Central Register of Controlled Trials; CINAHL = Cumulative Index to Nursing and Allied Health Literature; CNKI = China National Knowledge Infrastructure; ISI = Institute for Scientific Information; PQDD = ProQuest Dissertations & Theses Global; RCT = randomized controlled trial; WHO ICTRP = the World Health Organization International Clinical Trials Registry platform. *One trial examined music intervention and eye mask/earplugs and is counted under both categories. ** One trial examined relaxation interventions and back massage and is counted under both categories.

We identified 72 potentially relevant studies and retrieved them for further assessment. We included 30 studies (see the 'Characteristics of included studies' tables). We contacted the authors of five studies, Alexopoulou 2007; Andréjak 2013; Bosma 2007; Richards 1998; Wallace 1998, by email and retrieved details of study methods and data from them.

We excluded a total of 27 studies that did not meet the inclusion criteria (see the 'Characteristics of excluded studies' tables for detailed descriptions).

Ten trials registered on the US National Institutes of Health Ongoing Trials Register (www.clinicaltrials.gov) are ongoing (see the 'Characteristics of ongoing studies' tables for detailed descriptions), and five studies are awaiting classification (see the 'Characteristics of studies awaiting classification' tables).

Included studies

In this review, we included 30 randomized controlled trials, with 1569 participants; 12 trials using cross‐over design; and 18 trials using parallel group design. There were 29 randomized trials and one quasi‐randomized trial. Eight trials were conducted in China, one was conducted in Korea, one was conducted in Japan, 11 were conducted in Europe, and nine were conducted in the United States (see the 'Characteristics of included studies' tables for detailed descriptions).

Participants

The number of participants per study ranged from a minimum of six to a maximum of 136. Ten trials included ventilated participants (Alexopoulou 2007; Andréjak 2013; Bosma 2007; Cabello 2008; Córdoba‐Izquierdo 2013; Hu 2010; Jaber 2007; Parthasarathy 2002; Roche‐Campo 2013; Wallace 1998); most of these studies ventilated participants through an endotracheal tube or tracheostomy, and only one of these trials, Córdoba‐Izquierdo 2013, used non‐invasive ventilation. One study included both ventilated participants and non‐ventilated participants (Jaber 2007). Nine studies reported trials that were conducted in single‐bed rooms in the critical care unit (Alexopoulou 2007; Andréjak 2013; Borromeo 1998; Gragert 1990; Richards 1998; Richardson 2003; Su 2013; Toublanc 2007; Wallace 1998). Seven trials were conducted in coronary care units (Borromeo 1998; Gao 2008; Gragert 1990; Li 2011; Richards 1998; Ryu 2012; Wang 2012), one was performed in a cardiac surgical intensive care unit (Hu 2010), two were performed in a medicosurgical department of anaesthesia and resuscitation (Jaber 2007; Le Guen 2014), one was performed in a respiratory intensive care unit (ICU) (Toublanc 2007), one was performed in a pulmonary and critical care unit (Parthasarathy 2002), and the remaining studies were performed in medical ICUs.

Thirteen studies, Andréjak 2013; Bosma 2007; Córdoba‐Izquierdo 2013; Foreman 2013; Gao 2008; Hu 2010; Le Guen 2014; Parthasarathy 2002; Ruan 2006; Su 2013; Sha 2013; Toublanc 2007; Wang 2012, reported that baseline characteristics did not differ significantly between the groups.

Interventions

We included six trials of ventilator mode, eight trials using earplugs or eye masks or both, five trials of music interventions (which included one trial, Hu 2010, using earplugs and eye masks combined with music intervention), three trials of relaxation and imagery (which included one trial of back massage and relaxation intervention (Richards 1998)), one trial of back massage and relaxation intervention, one trial of foot massage combined with the use of a Chinese herb sleep pillow (Wang 2012), one trial of a foot bath intervention (Namba 2012), one trial of social support intervention through changing the ICU visit time for family members (Gao 2008), one trial of a nursing intervention (Li 2011), one trial of valerian acupressure (Chen 2012), one trial of ventilator type (Córdoba‐Izquierdo 2013), one trial of receiving mechanical versus spontaneous ventilation (Roche‐Campo 2013), one trial of aromatherapy (Borromeo 1998), and one trial of sound masking (using USASI noise, namely a continuous sound occurring at the same level over a long period) (Gragert 1990).

The interventions included in this review were heterogeneous with respect to components, methods, content, and intensity of use. The duration of the interventions ranged from 10 minutes, Chen 2012, to seven days (Wang 2012). Most cross‐over trials had no washout period between intervention periods (Alexopoulou 2007; Andréjak 2013; Bosma 2007; Cabello 2008; Jaber 2007; Martin 2008; Parthasarathy 2002; Roche‐Campo 2013; Toublanc 2007); only two trials used a washout period (Borromeo 1998; Namba 2012).

1. Optimizing ventilator mode, type, or management strategy

Six trials examined the effect of ventilator mode on sleep, namely three trials of assist‐control ventilation (ACV) versus pressure support ventilation (PSV) (Cabello 2008; Parthasarathy 2002; Toublanc 2007), two trials of proportional assist ventilation (PAV) versus PSV (Alexopoulou 2007; Bosma 2007), and one trial of pressure‐controlled ventilation (PCV) versus low PSV (Andréjak 2013).

One trial, Córdoba‐Izquierdo 2013, examined the effect of optimizing ventilator type on sleep.

One trial, Roche‐Campo 2013, examined the effect of mechanical versus spontaneous ventilation on sleep.

2. Earplugs or eye masks or both

We included eight trials using earplugs or eye masks or both. Four of these trials compared the use of earplugs versus no use of earplugs during regular night‐time sleeping hours (Martin 2008; Scotto 2009; Van Rompaey 2012; Wallace 1998). One trial compared the use of earplugs and eye masks combined with sleep‐inducing music versus no use of earplugs, no eye masks, and no music (Hu 2010). Two trials compared the use of earplugs and eye masks versus no use of earplugs and eye masks during night‐time (Le Guen 2014; Xie 2011). One trial compared oral melatonin, sound‐reducing headphones, and eye covers versus standard care (Foreman 2013). The duration of the interventions varied from one night, Le Guen 2014; Martin 2008; Scotto 2009; Wallace 1998, to four nights (Van Rompaey 2012).

3. Music intervention

Five studies included in this review used music intervention with sleep‐inducing or relaxing music, but the methods of the interventions, frequency and duration of music listening, and methods in the control group varied greatly between these trials. One trial compared earplug‐delivered sleep‐inducing music for 52 minutes versus control group (no music, but earplugs and eye shield worn) (Ryu 2012). One study compared a 45‐minute music‐listening intervention versus usual care without music (Su 2013). One trial combined the use of earplugs and eye masks with music listening versus no use of earplugs or eye masks and no music (Hu 2010). (We also counted this study under the eye mask/earplug category.) One trial compared a 20‐minute relaxing music therapy versus sitting and uninterrupted resting (Jaber 2007). One trial compared an individualized music intervention (12.30 p.m. to 1.30 p.m. and 8.30 p.m. to 9.30 p.m.) versus usual care during the period of ICU stay (Sha 2013).

4. Relaxation techniques

Three trials used relaxation techniques: Richardson 2003 used a combination of relaxation and imagery (13 to 18 minutes in length); Ruan 2006 used a combination of relaxation, imagery, and relaxing music; Richards 1998 used a combination of muscle relaxation, mental imagery, and music (a 7.5‐minute relaxation audiotape consisting of music; guided imagery; and muscle relaxation. We also included this trial under 'back massage' intervention below).

5. Massage

a) Back massage and relaxation intervention

Richards 1998 compared the effect of a back massage and relaxation intervention on sleep with two different groups: group one received a six‐minute back massage; group two received a teaching session on relaxation and a 7.5‐minute audiotape at bedtime consisting of muscle relaxation, mental imagery, and relaxing background music; group three received usual nursing care. The duration of the intervention was one night.

b) Foot massage or foot bath

Wang 2012 examined the effect of foot massage combined with use of a "sleep pillow" (ingredients: Chinese herbal medicine); the duration of the intervention was seven days.

Namba 2012 examined the efficacy of a foot bath intervention for sleep promotion.

6. Valerian acupressure

Chen 2012 compared valerian acupressure on the Shenmen, Neiguan, and Yongquan acupoints versus usual care; the duration of the intervention was one night.

7. Aromatherapy

Borromeo 1998 examined the effects of aromatherapy intervention on sleep.

8. Sound masking

Gragert 1990 compared sound masking (USASI noise) versus usual care.

9. Social support intervention and nursing intervention

Gao 2008 compared changing the ICU visit time for family members versus conventional care with standard visiting times.

Li 2011 compared a nursing intervention programme using the Roy Adaptation Model as a guide versus conventional care; the duration of the intervention was two weeks.

Outcomes

Not all trials measured all of the outcomes relevant for this review. Included studies examined objective sleep outcomes or subjective sleep outcomes or both.

Sleep was measured using polysomnography (Alexopoulou 2007; Andréjak 2013; Bosma 2007; Cabello 2008; Córdoba‐Izquierdo 2013; Namba 2012; Parthasarathy 2002; Richards 1998; Roche‐Campo 2013; Su 2013; Toublanc 2007Wallace 1998), ActiGraph (Chen 2012; Le Guen 2014), Bispectral Index (BIS) (Jaber 2007), electroencephalography (EEG) and methods of muscle tension (Foreman 2013; Xie 2011), nurse observation (Chen 2012; Gragert 1990; Gao 2008; Ruan 2006), and participant assessment (Borromeo 1998; Gragert 1990; Hu 2010; Le Guen 2014; Martin 2008; Richardson 2003; Ryu 2012; Scotto 2009; Toublanc 2007; Sha 2013; Van Rompaey 2012; Wang 2012; Xie 2011).

Sixteen trials used subjective sleep scales to measure sleep quality on the day following the intervention, but the sleep scales varied among these trials: five trials, Richardson 2003; Martin 2008; Scotto 2009; Su 2013; Ryu 2012, used the Verran/Synder‐Halpern (VSH (Snyder‐Halpern 1987)) Sleep Scale (although the versions of the VSH Scale used differed between these trials, and the rating methods were different); three studies, Borromeo 1998; Gragert 1990; Hu 2010, used the Richardson‐Campbell Sleep Questionnaire (RCSQ, a self‐reported visual analogy instrument (Richards 2000)); three trials, Li 2011; Sha 2013; Xie 2011, used a Chinese version of the Pittsburgh Sleep Quality Index (PSQI) scale (Liu 1996); one trial, Chen 2012, used the PSQI and Stanford Sleepiness Scale (SSS (Fichten 1995)); one trial, Wang 2012, used the Athens Insomnia Scale (AIS (Soldatos 2000)) to measure subjective sleep quality; one trial, Le Guen 2014, measured self‐assessment sleep quality by Spiegel score (Klimm 1987) and Medical Outcomes Study Sleep questionnaire (Hays 2005); and two trials, Toublanc 2007; Van Rompaey 2012, used participant‐perceived measures of sleep quality.

Two trials reported outcomes relating to the incidence of delirium (Le Guen 2014; Van Rompaey 2012). Van Rompaey 2012 assessed delirium using the validated Neelon/Champagne Confusion (NEECHAM) scale (Milisen 2005), which was based on the nurses' 24‐hour assessment of the level of processing information, the level of behaviour, and the physiological condition.

The majority of cross‐over trials included in this review only reported the whole‐period outcomes of the study. Two trials reported outcomes during the first period and the second period in addition to the whole period (Roche‐Campo 2013; Toublanc 2007).

Excluded studies

We excluded 27 studies (see the 'Characteristics of excluded studies' tables). We excluded these studies for the following reasons: four trials did not have relevant outcomes; 13 trials were not randomized or quasi‐randomized controlled trials; in six studies, the types of participants were not relevant; in two studies, the interventions were not relevant; and two articles were systematic reviews.

Risk of bias in included studies

For details of the 'Risk of bias' rating for each study and the reasons for each rating, please see the 'Characteristics of included studies' tables. A summary of the 'Risk of bias' judgements by study and domain (sequence generation, allocation concealment, blinding, incomplete data, and selective reporting) can be found in Figure 2 and Figure 3.

'Risk of bias' graph: review authors' judgements about each 'Risk of bias' item presented as percentages across all included studies.

'Risk of bias' summary: review authors' judgements about each 'Risk of bias' item for each included study.

Blinding

Because of the nature of the interventions, it was not possible to blind personnel or participants or both to the intervention in any of the included studies. Therefore, we considered that all studies were at a high risk of performance and detection bias by participants and personnel, although we note that this was potentially less of a factor for the objective outcomes (e.g., mortality and objective sleep variables).

Seventeen studies considered objective sleep measures, and nine of these studies, Andréjak 2013; Bosma 2007; Cabello 2008; Córdoba‐Izquierdo 2013; Richards 1998; Roche‐Campo 2013; Su 2013; Toublanc 2007; Wallace 1998, were at a low risk of performance and detection bias by outcome assessors because polysomnography (PSG) sleep records (i.e., objective sleep measures) were scored by an expert who was blinded to the randomization assignment. The risk of bias for outcome assessors was unclear in six studies (Alexopoulou 2007; Chen 2012; Foreman 2013; Jaber 2007; Namba 2012; Parthasarathy 2002), and there was a high risk of bias for outcome assessors in one study (Le Guen 2014).

Selective reporting

For two studies (Li 2011; Richardson 2003), it appeared that a degree of selective reporting had taken place, and we rated these studies as at a high risk of reporting bias. We considered 20 trials to be at a low risk of reporting bias, and it was unclear whether the remaining eight trials were at a risk of reporting bias.

Other potential sources of bias

Seven trials declared a conflict of interest; the other trials did not declare a conflict of interest, so we judged the potential bias to be "unclear" as we had insufficient information to permit a judgement. Most trials did not report a sample size calculation. Other potential sources of bias were evident in one trial (Richardson 2003); the author did not report the mean sleep scores on day one, day two, and day three in both groups, but reported the mean sleep scores on day one, day two, and day three by gender. We then combined the male group and the female group into a single group and calculated the mean sleep scores in both groups. The results showed that the mean sleep scores of the first night (namely baseline) were significantly different between the two groups. In Chen 2012, the baseline mean age and mean Acute Physiology Score (APS) scores of the experimental group were higher than those of the control group. In Córdoba‐Izquierdo 2013, the baseline Epworth Sleepiness Scale scores were higher in the NIVD group than in the NIVICU group. Sha 2013 did not assess the baseline of PSQI scores.

Effects of interventions

See: Table 1

Please see Table 1.

There was considerable clinical heterogeneity across the included studies due to the wide range of scales used to assess outcomes, the different participant populations, and study designs used (e.g., duration, time points). We could not pool the majority of results for meta‐analysis ‐ in which case, we have presented measures of treatment effect. If the published results did not provide sufficient detail to calculate between‐group differences and 95% confidence intervals, we present the data as reported in the study reports.

1 Primary outcome: objective sleep variables

In summary, the effects of non‐pharmacological interventions on objective measurements of sleep quality and quantity were inconsistent across studies. Overall, we rated the quality of the evidence as very low. The reasons for downgrading the quality of the evidence varied by intervention type and are summarized at the end of each subsection below.

a) Ventilator mode or type

Six cross‐over trials examined the effects of ventilator modes on objective sleep variables in ICU patients (Alexopoulou 2007; Andréjak 2013; Bosma 2007; Cabello 2008; Parthasarathy 2002; Toublanc 2007). All of these trials measured sleep using PSG, although there was inconsistency in the method of reporting outcomes between studies. Because of important clinical heterogeneity and missing data, we did not incorporate these studies into a meta‐analysis. We summarize below findings for these individual studies measuring PSG sleep variables (as reported by the authors) and present them in Table 2, Table 3, and Table 4.

1

Comparison of sleep quantity between ACV versus PSV

2

Comparison of sleep quantity between PAV versus PSV

3

Comparison of sleep quantity between PCV versus PSV

Three studies examined objective sleep variables in participants receiving ACV versus PSV (Cabello 2008; Parthasarathy 2002; Toublanc 2007).

i) One trial, Parthasarathy 2002, demonstrated a significant increase in Sleep Efficiency Index (SEI) in the ACV group (mean = 75, standard deviation (SD) = 5) compared with the PSV group (mean = 63, SD = 5) (P value < 0.05). However, no significant improvement in SEI was found by Cabello and colleagues (P value > 0.05; Cabello 2008).

ii) Two trials, Cabello 2008; Parthasarathy 2002, reported sleep fragmentation index, but only one, Parthasarathy 2002, indicated a significant reduction in sleep fragmentation index in the ACV group (mean = 54, SD =7) compared with the PSV group (mean = 79, SD = 7) (P value < 0.05). Cabello 2008 found no significant reduction in sleep fragmentation index (P value > 0.05).

iii) Toublanc 2007 reported no significant reduction in awakening index between ACV and PSV groups (P value > 0.05).

iv) Two trials, Cabello 2008; Parthasarathy 2002, measured the percentage of stage three and four sleep, but no significant difference was found between the PSV and ACV groups in either trial (P value > 0.05). However, during the second period of the cross‐over study by Toublanc et al (Toublanc 2007), higher percentages of stage three sleep (mean = 6.3, SD = 7.7 versus mean = 0.3, SD = 1.0) (P value < 0.01) and stage four sleep (mean = 5.4, SD = 13.2 versus mean = 0, SD = 0) (P value < 0.05) were observed in the ACV group compared with those in the low PSV group.

Two studies compared PAV versus PSV (Alexopoulou 2007; Bosma 2007).

i) In Alexopoulou 2007, SEI was significantly higher in the PAV group (mean = 98.9, SD = 2.3) compared with the PSV group (mean =87.7, SD = 16.4) (P value < 0.05). Bosma 2007 found no significant difference in SEI (P value > 0.05).

ii) No significant reductions in sleep fragmentation index and slow‐wave sleep (SWS) per cent were found in either trial (P > 0.05).

Only one study compared PCV versus PSV (Andréjak 2013).

i) SEI was significantly higher in the PCV group (mean = 61.5, SD = 25.1) compared with the PSV group (mean = 39.2, SD = 29.1) (P value < 0.01).

ii) A significant increase in the number of hours of REM sleep time was reported in the PCV group (mean = 3.4, SD=6.4) compared with the PSV group (mean = 0.8, SD = 2.1) (P value < 0.01).

iii) No significant difference in the percentage of stage three and four sleep was observed between groups (P value > 0.05).

Two studies examined the effect of ventilator type on objective sleep variables (Córdoba‐Izquierdo 2013; Roche‐Campo 2013). One study of 24 participants with acute hypercapnic respiratory failure requiring non‐invasive ventilation, Córdoba‐Izquierdo 2013, compared the use of conventional ICU ventilators versus dedicated non‐invasive ventilators and found no significant difference between the groups in sleep fragmentation index, total sleep time (TST), stage one per cent, stage two per cent, SWS per cent, and REM per cent (P value > 0.05).

One cross‐over study examined spontaneous ventilation versus mechanical ventilation at low levels of pressure support in 16 tracheostomized participants during weaning (Roche‐Campo 2013). Total sleep time was greater during mechanical ventilation than during spontaneous ventilation (183 minutes versus 132 minutes, P value = 0.04). This study found no significant difference between the groups in SWS time, REM time, and sleep fragmentation index (P value > 0.05).

We rated the quality of the evidence as low for the effect of ventilator mode or type on objective sleep variables, having downgraded once for inconsistency (findings differed between studies) and once for risk of selection bias.

b) Earplugs or eye masks or both

Two studies assessed the effect of eye masks or earplugs or both on objective sleep variables as measured using PSG (Foreman 2013; Wallace 1998). Due to clinical heterogeneity in study design, the results from these studies could not be combined statistically. Wallace 1998 reported significantly higher percentages of REM sleep during the night in the group assigned to earplugs compared with the control group (mean = 5.60, SD = 8.00 versus mean = 2.40, SD = 5.60) (P value = 0.04). No significant difference in other objective sleep variables (sleep period time, SEI, sleep maintenance efficiency index, number of awakenings) was found between the groups in this study (each P value > 0.05). Foreman 2013 examined objective sleep variables in 12 neurological ICU patients who received oral melatonin, sound‐reducing headphones, and eye covers versus standard care, finding no significant difference between the groups in terms of sleep architecture (no P value or 95% CI reported).

One quasi‐RCT of 75 ICU patients, Xie 2011, compared the use of earplugs and eye masks versus usual care on objective sleep variables, as measured by EEG. There was a greater improvement in the mean number of hours of SWS in the intervention group compared with the control group (SWS: post‐test mean = 2.18, SD = 0.34 versus post‐test mean = 1.43, SD = 0.28) (P value < 0.01) (REM: post‐test mean = 2.09, SD = 0.28 versus post‐test mean = 0.71, SD = 0.36) (P value < 0.01). A greater reduction in the mean number of hours of waking time was also reported in the intervention group compared with the control group (post‐test mean = 1.79, SD = 0.75 versus post‐test mean = 3.8, SD = 0.79) (P value < 0.01); no significant difference in NREM time was observed between groups (P value > 0.05).

One study of 41 postoperative patients compared the use of earplugs and eye masks versus usual care on objective sleep variables, as measured by ActiGraph (Le Guen 2014). This study found no significant between‐group difference (P value > 0.05) in sleep variables, including sleep efficiency, sleep fragmentation, sleep disruptions, movement numbers, or activity scores.

We rated the quality of the evidence as very low for the effect of earplugs or eye masks or both on objective sleep variables, having downgraded twice for inconsistency (findings differed between studies) and once for risk of selection bias.

c) Music intervention

One study examined the effects of listening to music (versus usual care) on PSG sleep variables in 28 ICU patients (Su 2013). The authors reported that participants in the music group had shorter stage two sleep time (P value = 0.014) and longer stage three sleep time (P value = 0.008) in the first two hours of the nocturnal sleep as calculated by generalized estimating equation analysis. No statistically significant differences in the mean total sleep time, sleep efficiency, and stage one sleep times were reported between groups (P value > 0.05).

One study measured objective sleep variables as measured by BIS (Jaber 2007). The author reported a significantly greater reduction in BIS in the music intervention group (post‐test mean = 81, SD = 10) compared with the control group (post‐test mean = 94, SD = 5) (P value < 0.01).

We rated the quality of the evidence as very low for the effect of music on objective sleep variables, having downgraded once for inconsistency (findings differed between studies), once for indirectness (only two small studies included), and once for risk of selection bias in Jaber 2007.

d) Relaxation techniques

Richards 1998 compared a six‐minute back massage versus relaxation intervention plus relaxing music (combined muscle relaxation, mental imagery, and audiotape) versus usual care (control). The study measured objective sleep variables using PSG in 69 older men with cardiovascular illness. Participants in the back‐massage group slept more than one hour longer than those in the control group (mean = 319.82, SD = 48.45 versus mean = 257.33, SD = 108.22; no significance value reported). This study found a significant difference among the three groups in SEI (control group: mean = 62.84, SD = 24.46; back‐massage group: mean = 77.32, SD = 10.53; relaxation group: mean = 73.13, SD = 15.66, F = 3.73) (P value = 0.03). No significant differences in other PSG sleep variables were found in this study.

We rated the quality of the evidence as very low for the effect of relaxation techniques on objective sleep variables, having downgraded once for risk of selection bias, once for indirectness (only one study population), and once for imprecision (large standard deviations).

e) Foot massage or foot bath

One study of six participants compared using foot baths at 40℃ for 10 minutes before sleep onset with usual care and measured PSG sleep (Namba 2012). There was no significant difference in total sleep time, sleep efficiency, time spent in REM or sleep stages, and sleep fragmentation (all P values > 0.05).

We rated the quality of the evidence as very low for the effect of foot massage/bath on objective sleep variables, having downgraded once for risk of selection bias, once for indirectness (only one study population), and once for imprecision.

f) Other interventions

None of the studies examined the effect of valerian acupressure, aromatherapy, sound masking, or nursing/social interventions on objective sleep variables.

2) Primary outcome: length of ICU stay

We rated the quality of the evidence as very low for this outcome, having downgraded once for risk of selection bias, once for indirectness (only one population considered), and once for imprecision (wide confidence intervals).

a) Earplugs or eye masks or both

Hu 2010 examined the effect of earplugs plus eye masks plus sleep‐inducing music versus usual care on the length of ICU stay. No significant difference in the length of ICU stay was found between groups (MD = ‐5.90, 95% CI ‐16.42 to 4.62) (P value > 0.05).

b) Other interventions

No other trials examined the effect of the other non‐pharmacological intervention types on the length of ICU stay.

3) Primary outcome: mortality

None of the included studies examined mortality.

4) Secondary outcome: adverse events

We rated the quality of the evidence as very low for this outcome, having downgraded once for risk of selection bias, once for indirectness (the evidence was based only on studies of ventilator mode or type), and once for imprecision (large standard deviations reported in individual studies).

a) Ventilator mode or type

Five trials assessed the effect of ventilator mode on adverse events, such as central apnoeas, patient‐ventilator asynchronies, and ineffective efforts. In Bosma 2007, total patient‐ventilator asynchronies per hour were more frequent during PSV than during PAV (53 ± 59 versus 24 ±15) (P value = 0.02); episodes of central apnoeas were observed during the night with PSV, whereas no participants showed central apnoeas during the night on PAV. In Cabello 2008, no apnoeas occurred during ACV, whereas nine of 15 participants presented sleep apnoeas during PSV, and the mean number of ineffective efforts per hour of sleep were similar with ACV, automatically adjusted pressure support ventilation (aPSV), and clinically adjusted pressure support ventilation (cPSV) (P value > 0.05). In Parthasarathy 2002, apnoeas occurred in six of 11 participants during PSV alone, but not during ACV; the use of PSV with dead space decreased the frequency of apnoeas significantly (P value < 0.05). In Alexopoulou 2007, the two modes (PAV and PSV) had comparable effects on respiratory variables, particularly at high assist, and a significant proportion of participants in both groups developed periodic breathing during sleep. In Roche‐Campo 2013, one participant experienced periodic breathing and one participant experienced central apnoeas regardless of the ventilatory mode used; nobody exhibited ineffective efforts.

b) Other interventions

No trials of the other non‐pharmacological interventions examined adverse events.

5) Secondary outcome: delirium

We rated the quality of the evidence as low for this outcome, having downgraded once for risk of selection bias and once for imprecision (wide confidence intervals ‐ see Table 1).

a) Earplugs or eye masks or both

Two studies examined the effect of earplugs or eye masks or both on the risk of delirium (Le Guen 2014; Van Rompaey 2012). Van Rompaey and colleagues used the validated Neelon and Champagne Confusion Scale (NEECHAM) (Van Rompaey 2008). In Le Guen 2014, the author did not report the method of assessment of delirium. A meta‐analysis of these two studies showed that use of earplugs or eye masks or both significantly decreased the risk of delirium or confusion (risk ratio (RR) 0.55, 95% CI 0.38 to 0.80) (P value = 0.002) (Analysis 1.1; Figure 4).

Forest plot of comparison: earplugs or eye mask or both versus usual care, outcome: 2.2 incidence of delirium and confusion.

Analysis

Comparison 1 Ear plugs or eye mask versus usual care or both, Outcome 1 Incidence of delirium and confusion.

b) Other interventions

No trials of the other non‐pharmacological interventions examined delirium.

6) Secondary outcome: subjective sleep quantity or quality

Overall, we rated the quality of the evidence for this outcome as low. The reasons for downgrading the quality of the evidence varied by intervention type and are summarized at the end of each subsection below.

a) Ventilator mode or type

Toublanc 2007 reported that self‐perceived quality of sleep in ICU patients was poor, but did not compare subjective sleep quality between the different ventilator modes.

b) Earplugs or eye masks or both

Six studies of earplugs or eye masks or both assessed sleep quality or quantity using subjective sleep scales (Hu 2010; Le Guen 2014; Martin 2008; Scotto 2009; Van Rompaey 2012; Xie 2011); the scales used varied among these trials.

Two studies, involving 120 participants, compared earplugs and eye masks versus usual care and assessed nurse‐measured (subjective) sleep quantity (Le Guen 2014; Xie 2011). Meta‐analysis of these two studies showed that total sleep time was significantly greater in the intervention group compared with the control group (MD 2.19 hours, 95% CI 0.41 to 3.96, two studies, 116 participants). However, there was evidence of heterogeneity between studies for this outcome (I² statistic = 79%; P value = 0.03) (Analysis 1.2; Figure 5).

Forest plot of comparison: Use of ear plugs and eye mask versus usual care, outcome: 2.3 subjective sleep quantity; total sleep time (hours).

Analysis

Comparison 1 Ear plugs or eye mask versus usual care or both, Outcome 2 Total sleep time.

Two studies, Hu 2010 and Xie 2011, compared the use of earplugs and eye masks versus usual care and assessed subjective sleep quality using the RCSQ and PSQI scales, respectively. As Hu 2010 combined music and the use of earplugs/eye masks in the intervention group whereas Xie 2011 examined earplugs plus eye masks only, we could not pool data from the two studies. Subjective sleep quality in the intervention group was greater in the intervention versus control groups of both studies. In Hu 2010, the mean difference in the Chinese version of RCSQ scores of perceived quality (0 = better sleep, 100 = poor sleep) for intervention versus control was ‐27.00 (95% CI ‐40.15 to ‐13.85). In Xie 2011, the mean difference in PSQI score (0 = best sleep, 21 = worst sleep) for intervention versus control was ‐7.25 (95% CI ‐8.46 to ‐6.04).

Le Guen 2014 evaluated subjective sleep quality using the Spiegel score for which higher scores indicate a better sleep quality; a total score below 15 signifies a pathological sleep, and a score above 20, good sleep. Postoperatively, the mean Spiegel score in the earplug and eye mask group was 20 (SD = 4) compared with 15 (SD = 5) in the control group (comparison P value = 0.006). Additionally, only 50% of the participants in the intervention group reported the need for a nap compared with 95% of those in the control group (P value = 0.001).

Martin 2008 reported no significant difference in VSH sleep scores between earplug and usual care groups (post‐test mean = 56.7, SD = 25.6 versus post‐test mean = 59.2, SD = 27.0; significance value not reported). Scotto 2009 also assessed sleep quality using the VSH sleep score. The author reported that use of earplugs improved the subjective sleep quality (P value < 0.05), but no mean scores were reported.

One study, Van Rompaey 2012, of 136 participants compared sleep perception using five dichotomous questions on the self‐reported sleep quality of the participant, which they categorized as: bad sleep (sum < 2), moderate sleep (sum 2 < 4), and good sleep (sum ≥ 4). More participants perceived good sleep in the intervention group than those in the control group after the first night (P value = 0.042, no Chi² test value reported).

Overall, we deemed the quality of the evidence for the effect of earplugs or eye masks or both on objective sleep variables as low, having downgraded once for inconsistency (findings differed between studies) and once for risk of selection bias.

c) Music interventions

Four studies of music intervention reported subjective sleep quality. One study, Sha 2013, used the PSQI sleep scale, and one study, Hu 2010, used a Chinese version of RSCQ. We could not pool data from these studies as they reported no post‐test PSQI total scores (Sha 2013), and the sleep quality scales were incompatible (Hu 2010). In Sha 2013, the subjective sleep quality, sleep time, sleep efficiency, and total PSQI scores were significantly improved in the intervention group compared with the control group (P value < 0.05). Additionally, the incidence of sleep disorder in the music intervention group was significantly lower than that in the control group (P value = 0.036).

Two studies examined subjective sleep quality using different versions of the VSH sleep scale (Ryu 2012; Su 2013). However, Ryu 2012 combined music with the use of earplugs and eye masks, whereas Su 2013 did not; for this reason, we could not combine the results in a meta‐analysis. Ryu 2012 reported that participants receiving a music intervention had improved sleep quality versus those receiving usual care (standardized mean difference (SMD) 0.93, 95% CI 0.15 to 1.72; N = 28). Similarly, sleep quality was improved in participants receiving music intervention plus eye masks and earplugs versus usual care (SMD 1.37, 95% CI 0.79 to 1.94; N = 58; Su 2013).

Overall, we deemed the quality of the evidence for the effect of music interventions on objective sleep variables as very low, having downgraded once for inconsistency (findings differed between studies) and twice for a high risk of selection bias.

d) Relaxation techniques

One study measured perception of sleep quality using the VSH sleep scale (Richardson 2003). No differences were observed between control and experimental sleep scores on day one, two, and three (each P value > 0.05; no mean sleep score values were reported by group). We calculated mean sleep scores and used intention‐to‐treat (ITT) analysis; the results showed the intervention group (namely a combination of relaxation and imagery) exhibited significantly less change in sleep scores from the first night to the third night (MD ‐13.52, 95% CI ‐34.24 to 7.20), indicating better sleep in the intervention group (higher sleep scores indicated a perception of improved sleep in this trial). However, we also found the baseline of sleep scores in the intervention group was significantly higher than those in the control group, which resulted in a high risk of selection bias in the study, so it was difficult to ascertain if there was a real effect.

One study measured sleep quality and quantity by nursing observation (Ruan 2006). The main outcomes were trichotomous types; the study classified the outcome of the time taken to fall asleep into "less than 30 minutes", "0 to 60 minutes", or "greater than 60 minutes", and it classified the outcome of total nocturnal sleep time into "less than three hours", "three to five hours", or "greater than five hours". Using methodology recommended in the Cochrane Handbook for Systematic Reviews of Interventions (Higgins 2011), we transformed the published data into a dichotomous format by combining adjacent categories together, using "greater than 60 minutes" and "greater than five hours" as cut‐off points. The results showed that it took significantly less time to fall asleep in the intervention group than in the control group (RR 0.34, 95% CI 0.11 to 1.06), but there was no significant difference between the groups for total nocturnal sleep time (RR 0.26, 95% CI 0.09 to 0.74).

We deemed the quality of the evidence for the effect of foot massage/bath on objective sleep variables as very low, having downgraded once for indirectness (evidence based on two small populations), once for risk of selection bias, and once for precision (wide confidence intervals).

e) Foot massage or foot bath

In Namba 2012, the participants claimed that they slept well the night after receiving a foot bath. One study, Wang 2012, of 104 participants with sleep problems in a coronary critical care unit compared foot massage plus 'sleep pillow' (ingredients: Chinese herbal medicine) and measured perceived sleep quality using the Athens Insomnia Scale (AIS). This study found that the mean change scores of AIS in the intervention group were higher than those in the control group (mean = 1.06, SD = 0.72 versus mean = 0.74, SD = 0.61) (P value < 0.05). We deemed the quality of the evidence for the effect of foot massage/bath on objective sleep variables as low, having downgraded once for indirectness (evidence based on two small populations) and once for risk of selection bias.

f) Valerian acupressure

One study of 85 ICU patients, Chen 2012, compared valerian acupressure on the Shenmen, Neiguan, and Yongquan acupoints versus usual care and measured subjective sleep quality using the Stanford Sleepiness Scale (SSS). This study found that, compared with the control group, the acupressure group had lower SSS ratings (i.e., better sleep; mean = 2.5, SD = 0.5 versus mean = 3.4, SD =1.1) (P value < 0 .001) and a greater number of hours sleep as observed by nursing staff (mean = 3.4, SD = 1.7 versus mean = 2.6, SD = 1.5) (P value < 0.05 ). We calculated the mean changes and the standard deviations in each group from baseline and calculated the mean difference. We found evidence of a difference between the two groups for number of hours of sleep (MD 0.7, 95% CI 0.29 to 1.11) (P value = 0.0008) and waking frequency (MD ‐4.30, 95% CI ‐6.36 to ‐2.24) (P value < 0.0001), but not for SSS ratings (MD ‐0.10, 95% CI ‐0.35 to 0.15) (P value = 0.44). We deemed the quality of the evidence for the effect of valerian acupressure on objective sleep variables as low, having downgraded once for indirectness (evidence based on one small population) and once for risk of selection bias.

g) Aromatherapy

One study compared aromatherapy intervention versus usual care and measured perceived sleep quality by RCSQ (Borromeo 1998). The study indicated no significant between‐group differences in sleep scores (intervention group: mean = 59.84, SD = 2.91; control group: mean = 63.28, SD = 2.48) (P value > 0.05). We deemed the quality of the evidence for the effect of aromatherapy on objective sleep variables as low, having downgraded once for indirectness (evidence based on one small population) and once for risk of selection bias.

h) Sound masking

One study of 40 older patients in a critical care unit assessed the effect of sound masking on subjective sleep quality measured by RCSG and nursing observation (Gragert 1990). The results indicated a significant difference in mean SEI between the intervention group and the control group (75% versus 61%; P value = 0.016), a greater total sleep time (308.70 minutes versus 249.5 minutes, P value = 0.012), and a reduced sleep latency time (35.12 minutes versus 102.60 minutes, P value = 0.000). No standard deviations were provided. No significant difference was seen in the number of awakenings (P value = 0.60). The following six variables were scored from 0 to 100 mm using the RCSQ: sleep depth, falling asleep, awakenings, returning to sleep, quality of sleep, and noise level (0 represented the best possible score, and 100 represented the worst possible score). The results showed that there was greater sleep depth (81.55 versus 54., P value = 0.001), less sleep latency (79.80 versus 56.15, P value = 0.002), and fewer awakenings (79.40 versus 56.20, P value = 0.002) in the intervention group compared with the control group. Subjective sleep quality was greater (81.20 versus 54.60, P value = 0.002); participants had less difficulty returning to sleep (79.90 versus 58.35, P value = 0.005) and lower subjective impressions of the noise level during the night‐time (90.85 versus 38.40, P value = 0.000) in the intervention group compared with the control group. We deemed the quality of the evidence for the effect of sound masking on objective sleep variables as low, having downgraded once for indirectness (evidence based on one small population) and once for risk of selection bias.

i) Nursing intervention or social intervention

One study, Gao 2008, compared changing the ICU visiting time for family members versus conventional care and demonstrated a significant increase in hours of total sleep time in the intervention group (post‐test mean = 6.7, SD = 1.1 versus post‐test mean = 3.6, SD = 2.4) (P value < 0.05).

One study, Li 2011, compared a nursing intervention programme with the Roy Adaptation Model as a guide versus conventional care and measured subjective sleep quality by PSQI (0 = better sleep, 21 = worse sleep). The author reported a significantly higher subjective sleep quality in the intervention group than in the control group (post‐test mean = 5.57, SD = 2.62 versus post‐test mean = 10.03, SD = 2.62) (P value < 0.05).

7. Secondary outcome: PTSD

None of the included studies examined PTSD.

8. Secondary outcome: participant satisfaction

a) Music interventions

One trial reported that five participants did not complete the study because they refused or resented the music therapy (Jaber 2007).

b) Other interventions

No trials examined the effect of the other non‐pharmacological intervention types on participant satisfaction.

9. Secondary outcome: economic outcomes

None of the included studies examined economic outcomes.

Discussion

Summary of main results

We included non‐pharmacological interventions, such as ventilator modes and type, earplugs or eye masks or both, massage, relaxation techniques, foot baths, music interventions, nursing interventions, valerian acupressure, aromatherapy, and the use of sound masking, in this review. Thirty studies, with a total of 1569 adult participants, were eligible for inclusion, three of which provided data suitable for meta‐analysis (all three studies assessed the use of earplugs or eye masks or both). Outcomes included objective sleep outcomes (as measured by polysomnography (PSG), Bispectral Index (BIS), or ActiGraph), subjective sleep quality and quantity by participant assessment or nursing observation, risk of delirium during intensive care unit (ICU) stay, participant satisfaction, length of ICU stay, and adverse events.

We considered the overall quality of the evidence for an effect of non‐pharmacological interventions on objective sleep variables in ICU patients as very low. Clinical heterogeneity prevented meaningful meta‐analysis of data from individual studies that examined the same intervention, and findings across studies of the same intervention were often inconsistent; the following text discusses our findings for this outcome by intervention type.

Four included studies examined the effect of earplugs or eye masks or both on objective sleep variables, all versus usual care (i.e., without using earplugs or eye masks). Individual studies provided some evidence that the use of earplugs or eye masks or both may increase rapid eye movement (REM) sleep time (Wallace 1998; Xie 2011) and non‐REM (NREM) 3˜4 time (Xie 2011). However, the trials contributing evidence for this outcome were potentially at a risk of selection bias, and there were inconsistent findings between studies (Le Guen 2014). Therefore, our overall rating of the evidence for an effect of earplugs or eye masks or both on objective sleep variables was very low. Mechanical ventilation has been cited as an important contributing factor to sleep disruption, and the optimization of ventilator mode is recommended for sleep promotion in ICU patients (Friese 2008; Parthasarathy 2004). Six randomized cross‐over studies also examined the effect of ventilator mode or type on objectively measured sleep variables (Alexopoulou 2007; Andréjak 2013; Bosma 2007; Cabello 2008; Parthasarathy 2002; Toublanc 2007). Clinical heterogeneity in the types and methods of interventions assessed and the specific outcomes measured meant that it was not possible to pool data from these studies.

Results from individual studies suggested that optimizing ventilator modes may improve sleep quality and reduce patient–ventilator asynchrony. In particular, pressure‐controlled ventilation mode (PCV), assist‐control ventilation mode (ACV), and proportional assist ventilation (PAV) mode appeared to offer some benefit in terms of sleep quantity or quality or both compared with pressure support ventilation mode (PSV). For example, in one study, Toublanc 2007, participants on ACV had lower wakefulness and longer stage one and two NREM sleep than participants on PSV. In a separate study (Parthasarathy 2002), differences in respiratory rate, mechanical expiratory time, mechanical inspiratory time, and end‐tidal CO₂ between sleep and wakefulness were greater during PSV than during ACV. However, we considered many of the included studies to be at a risk of selection bias, and findings were inconsistent between studies. For example, Parthasarathy 2002 reported that participants with ACV had a higher Sleep Efficiency Index (SEI) and lower sleep fragmentation than those during PSV, whereas Cabello 2008 reported no significant difference in SEI and sleep fragmentation. In addition to ventilator mode, the effect of ventilator type was also examined. One included study, Córdoba‐Izquierdo 2013, examined the effects of dedicated non‐invasive ventilators versus conventional ICU ventilators on sleep and reported no significant difference between groups. Similarly, another included study, Roche‐Campo 2013, reported that sleep quality was similar during mechanical ventilation (MV) and spontaneous ventilation (SV), but noted a greater quantity of sleep during MV than during SV in tracheostomized participants with prolonged weaning. Both studies were of an unclear risk of selection bias and represented only small populations of participants. Overall, we rated the quality of the evidence for the effect of ventilator mode or type on objective sleep variables as low. Similarly, the quality of evidence for an effect of music interventions on objective sleep variables was very low, with only two studies contributing relevant data, which we could not pool because of clinical heterogeneity. The two included studies reported contrasting findings: in one study, Jaber 2007, music interventions appeared effective in reducing the BIS with a difference of 13 points between groups. However, Su 2013 reported no effect of music interventions on PSG sleep outcomes.

Only one included study, Hu 2010, incorporated length of ICU stay as an outcome (a secondary outcome for this review). No significant effect of earplugs plus eye masks was found on length of ICU stay. We rated the overall quality of the evidence for this outcome as very low. None of the interventions examined in this review were assessed in relation to effect on mortality.

In terms of the review's secondary outcomes, few included studies assessed the effect of the interventions on adverse events in ICU patients. There was some evidence that ventilator mode influenced the incidence of adverse events, such as central apnoeas and patient‐ventilator asynchronies. Generally, more adverse events were noted with PSV compared with ACV or PAV. For example, two included studies reported that no central apnoeas occurred during ACV whereas more than 50% of participants had apnoeas during PSV (Cabello 2008; Parthasarathy 2002). However, clinical heterogeneity between studies prevented meta‐analysis, and we rated the quality of the evidence for this outcome (and thus the effect of ventilator mode on adverse events) as low.

Two included studies examined the incidence of delirium in ICU patients (Le Guen 2014; Van Rompaey 2012). Both of these studies examined the effect of earplugs or eye masks or both, and we pooled data from these studies for meta‐analysis. In participants using earplugs or eye masks or both, the risk of delirium was lower than for participants in the control group (risk ratio (RR) 0.55, 95% confidence interval (CI) 0.38 to 0.80). Assuming an incidence of delirium of 489 per 1000 people in the ICU with usual care, we estimated that 220 fewer people per thousand would experience delirium if using earplugs or eye masks or both (CI 98 to 303 fewer people per thousand). However, we rated the quality of the evidence for this finding as low.

Several studies assessed subjective sleep quantity or quality with the various non‐pharmacological interventions in ICU patients (Borromeo 1998; Chen 2012; Gao 2008; Gragert 1990; Hu 2010; Le Guen 2014; Li 2011; Martin 2008; Namba 2012; Richardson 2003; Ruan 2006; Ryu 2012; Scotto 2009; Sha 2013; Su 2013; Toublanc 2007; Van Rompaey 2012; Wang 2012; Xie 2011). Overall, we rated the quality of the evidence for objective sleep quality/quantity as low. Using various subjective scales, six studies individually reported some benefit of earplugs or eye masks or both on subjective sleep quality (Hu 2010; Le Guen 2014; Martin 2008; Scotto 2009; Van Rompaey 2012; Xie 2011). Pooled data from two of these studies showed a benefit for the use of earplugs/eye masks compared with usual care (Le Guen 2014; Xie 2011; 116 participants). The mean difference in total sleep quantity versus usual care was 2.19 hours (95% CI 0.41 to 3.96) although we observed evidence of heterogeneity (I² statistic = 79%). The quality of the evidence for the effect of this intervention on sleep quantity (assessed subjectively) was low due to heterogeneity and an unclear or high risk of selection and detection bias in these studies. Individual studies also provided some evidence that music interventions may improve subjective sleep quantity or quality (Ryu 2012; Sha 2013; Su 2013). However, findings were inconsistent across studies, and the studies had a high risk of selection bias. Therefore, we considered the quality of the evidence for an effect of music intervention on subjective sleep quantity/quality as very low. Several included studies examined alternative and complementary therapies; relaxation techniques (Richardson 2003; Ruan 2006), foot massage or foot bath (Namba 2012; Wang 2012), acupressure (Chen 2012), nurse or social intervention (Gao 2008; Li 2011), and sound masking (Gragert 1990) may offer some benefit in terms of subjectively measured sleep quantity or quality. However, the number of studies per intervention type was minimal (i.e., one or two studies), and the studies had an unclear or high risk of selection bias. Therefore, we rated the quality of the evidence for an effect of these interventions on subjectively measured sleep quantity/quality as low.

None of the interventions examined in this review were assessed in relation to mortality, risk of post‐traumatic stress disorder, or economic cost.

Overall completeness and applicability of evidence

The review included 29 randomized controlled trials (RCTs) and one quasi‐RCT. Because of the small number of studies per intervention and the different outcomes used across studies, we could not incorporate many studies into meta‐analyses in this review.

We found very limited evidence supporting non‐pharmacological interventions, such as massage, acupressure, imagery relaxation, nursing intervention, and social support. Most of these trials had small sample sizes, and none of the trials measured longer‐term clinical outcomes.

Interestingly, we found that ongoing studies are assessing several other non‐pharmacological interventions, including environmental modification, behavioural interventions, massage therapy, and 'device modifications' (see Ongoing studies). The excluded studies also examined several other non‐pharmacological interventions; these included aromatherapy (Cho 2013), use of earplugs and eye protective devices (House 2003; Koo 2008), an ICU‐wide quality improvement intervention (Kamdar 2013), therapeutic touch (Cox 1999), a postoperative pain treatment programme (Diby 2008), a sedation wake‐up trial and spontaneous breathing trial (Figueroa‐Ramos 2010), and implementing a "quiet time" protocol to reduce ICU environmental stimuli (Olson 2001). We excluded the majority of these trials as they were not RCTs, and most used non‐equivalent group designs.

The frequency and duration of the interventions varied widely across the trials. There were relatively small numbers of participants in all of the included studies, and few studies used power analysis, thereby, limiting study power. It was often difficult to collate and interpret information from the included studies due to inconsistency in the outcomes studied between the included trials. For example, few studies reported the same sleep outcomes or type of data with respect to PSG sleep variables. Similarly, few studies that assessed subjective sleep outcomes used the same sleep scales to measure subjective sleep quality. All of these factors contributed to our overall rating of the quality of the evidence using Grading of Recommendations Assessment, Development and Evaluation (GRADE). None of the included trials provided data on the effects of the non‐pharmacological interventions on mortality, risk of post‐traumatic stress disorder (PTSD), and cost effectiveness in ICU patients.

Quality of the evidence

A large number of the included studies had an unclear or high risk of allocation bias as methods of random sequence generation or allocation concealment or both were often inadequately reported or inappropriate. Furthermore, blinding of participants and personnel was often not possible for non‐pharmacological treatments, such as massage, use of earplugs and eye masks, imagery, relaxation, music therapy, or social support. As many of the trials in this review included subjective outcomes, such as subjective sleep scores, there was a high risk of performance bias associated with many of the studies. For many of the included studies, there was a need for additional methodological and statistical information, which if available, could have improved the quality of the evidence in the review. Additionally, many of the included studies provided insufficient information about general characteristics before randomization, and the majority of included studies had relatively small numbers of participants (most trials did not use power analysis), thus, limiting the power of the trials. Finally, due to substantial clinical heterogeneity, it was generally not possible to pool data across studies of the same intervention type, and findings from individual studies of the same intervention type were often inconsistent. In summary, all of these factors provided rationale for rating the quality of the evidence as low or very low (Table 1).

Potential biases in the review process

Our goal was to determine whether a range of non‐pharmacological interventions were effective for sleep promotion in ICU patients. We developed our search strategy to cover as many terms as possible. We searched all available databases, checked the reference lists of all relevant trials, and included trials without restricting language for both published and unpublished studies. Where necessary, we contacted the authors for additional unpublished information. However, it remains possible that we missed some published and unpublished trials. In the several instances where we contacted lead authors to request additional data and detailed information regarding research practice, we often failed to receive a reply from the authors (See Characteristics of included studies).

Agreements and disagreements with other studies or reviews

Music interventions have been cited as helpful measures to improve mood and reduce anxiety in coronary heart disease patients (Bradt 2009) and mechanically ventilated patients (Bradt 2010) and to reduce pain in cancer patients (Bradt 2011). In a systematic review (de Niet 2009), music‐assisted relaxation had a moderate effect on the sleep quality of participants with sleep complaints, possibly via effect on psychological outcomes (e.g., by assisting the relaxation for ICU patients). These findings are supported by those of a Cochrane systematic review, which suggested that music listening may have a large anxiety‐reducing effect on mechanically ventilated patients (Bradt 2014). These reviews reported no adverse reactions or outcomes relating to participant satisfaction.

An earlier systematic review by Richards and colleagues, Richards 2000a, examined the effects of massage on relaxation, comfort, and sleep in acute and critical care settings. In agreement with our findings, the review concluded that the clinical data were insufficient and further studies were required. Another systematic review, Richards 2003, presented the complementary and alternative therapies for promoting sleep in critically ill patients. The review searched the Cumulative Index to Nursing and Allied Health Literature (CINAHL) and MEDLINE databases and limited to papers in the English language from 1982 to 2002. Therapies included massage, relaxation technique, aromatherapy, therapeutic touch, environmental interventions, music therapy, and alternative sedatives. Although this review focused on the interventions and did not assess quality of the evidence, the authors conclusions were similar to those that we obtained: that there is currently insufficient evidence relating to the efficacy of non‐pharmacological interventions for sleep promotion in critically ill patients. A more recent systematic review, Tamrat 2014, identified non‐pharmacologic interventions for improving sleep quality and quantity of non‐intensive care unit inpatients. Again, this review found insufficient evidence to support the use of any non‐pharmacologic intervention for improving sleep quality or quantity in general inpatients. Finally, it will be interesting to examine our findings alongside those of a future Cochrane systematic review, which plans to evaluate the use of pharmacological agents for the promotion of sleep in the intensive care unit (Evans 2016).

Authors' conclusions

Implications for practice

Mechanical ventilation is an important contributing factor to sleep deprivation. In this review, several studies investigated the effects of ventilator modes on sleep outcomes, although we were unable to perform meta‐analysis of these studies. There was some evidence from individual studies to suggest that pressure‐controlled ventilation mode, assist‐control ventilation mode, and proportional assist ventilation mode may all improve sleep quantity or quality or both compared with pressure support ventilation mode. However, we noted some inconsistent findings between studies, and we rated the overall quality of the evidence as very low.

Our findings suggest that non‐pharmacological interventions, such as the use of earplugs or eye masks or both, may have some beneficial effects on sleep promotion and potentially decrease the risk of delirium in intensive care unit (ICU) adult patients. However, again, the quality of the evidence was generally low due to inconsistency in the findings of the contributing studies and the risk of bias associated with these studies. If using earplugs and eye masks, careful consideration should be given to implementation. For example, Scotto 2009 reported that some ICU patients were unwilling to use earplugs or eye masks or both because they found them uncomfortable or they fell out during sleep. Therefore, it may be important to provide alternative designs of earplugs or eye masks, or for clinical staff to help with the correct insertion of the earplugs.

Implications for research

The quality of existing evidence relating to the use of non‐pharmacological interventions for sleep promotion in ICU patients is low or very low. Whilst these interventions are often difficult to assess in the ICU setting and some of the methodological difficulties (e.g., blinding) relate to the nature of the interventions, we have several recommendations for future research in this area.

Generally, future studies should ensure the following:

1. Provide power calculations so that adequate sample sizes are used and where possible use as large a sample size of participants as is feasible.

2. Ensure low risk of bias through rigorous methodological development and reporting. For example, trials need to use reliable methods of allocation concealment, and methods of blinding should be as robust as possible. It is essential that trial design methods and outcomes are better reported, including randomization methods, loss to follow up, and details of prespecified outcomes measures.

3. Include an assessment of sleep‐related outcomes using polysomnography, which represents the gold standard of sleep measurement; relatively few published studies use this technique.

4. Outcomes should focus not only on sleep outcomes but also on the clinical outcomes, such as mortality, incidence of adverse events, or the risk of delirium or PTSD. Greater inclusion of outcomes relating to participant satisfaction, length of ICU stay, or health economics would also be desirable.

5. Include a validated sleep scale to measure subjective sleep quality. (A validated consensus instrument is required for comparison of studies in different countries.)

Specifically, we would recommend that more research is needed to test the effects of music intervention on objective sleep outcomes, ideally using polysomnography (PSG). A greater volume of research is needed for interventions, such as massage, acupressure, music therapy, environmental intervention, behaviour therapy, and psychological support, all in the ICU setting. (These interventions are used widely for sleep promotion in other clinical settings.)

Finally, we note that the analysis of data from cross‐over trials is critical for systematic reviews in this area. Therefore, a consensus in the method of reporting outcomes from cross‐over trials is required (e.g., reporting first period data and full period data separately). We also recommend that cross‐over trials include an adequate washout period between interventions; an inadequate washout period could potentially confound the findings of studies where the intervention serves to improve sleep via anxiolytic effects.

What's new

Acknowledgements

We would like to thank Professor Wu Taixiang (Chinese Cochrane Centre); Professor Chen Junmin (Department of Haematology and Rheumatology, The First Affiliated Hospital of Fujian Medical University); Dr Karen Hovhannisyan (Cochrane Anaesthesia Review Group (CARG) Trials Search Co‐ordinator); and Jane Cracknell (Cochrane Anaesthesia, Critical and Emergency Care (ACE) Managing Editor).

We would like to thank Mathew Zacharias (content editor), Georgopoulos Dimitris, G Iapichino, G Mistraletti, Matthew Bailey (peer reviewers), NL Pace (statistical editor), and Janet Wale (consumer editor) for their help and editorial advice during the preparation of the protocol (Hu 2010) for the systematic review.

We would like to thank Bronagh Blackwood (content editor); Janet Wale (consumer editor); Matthew Bailey, Jaap Lancee, Paul Montgomery, and Paula L Watson (peer reviewers) for their help and editorial advice during the preparation of this systematic review.

Appendices

Appendix 1. Interventions

01 Psychological interventions, cognitive or behavioural therapy such as music therapy, back massage, muscle relaxation, imagery, therapeutic touch.

02 Environmental interventions, such as noise reduction, lighting control, synchronization of ICU activities with daylight.

03 Social support interventions

04 Physical therapy modalities

05 Equipment modification, including mechanical ventilation.

06 Comentary therapy such as aromatherapy, herbs, acupuncture, acupressure.

Appendix 2. Search strategy for CENTRAL

Appendix 3. Search strategies

01 Search Strategy for MEDLINE (via OVID 1950 to May 2014)

1. Complementary Therapies/ or Music Therapy/ or Massage/ or Muscle Relaxation/ or "Imagery (Psychotherapy)"/ or Cognitive Therapy/ or Behavior Therapy/ or Social Support/ or Physical Therapy Modalities/ or Aromatherapy/ or ((Music or complementary or alternative or cognitive or behavioural) adj3 therapy*).ti,ab. or (imagery or massage or muscle relaxation or therapeutic touch or aromatherapy).ti,ab. or ((environmental or cognitive or behavioural or interventions or social support) adj3 intervention*).ti,ab. or (nighttime light or noise level* ).ti,ab.
2. exp Sleep/ or (sleep adj3 (promot* or help* or support* or Initiat*)).mp. or sleep.ti,ab.
3. 1 or 2
4. exp Critical Illness/ or exp Critical Care/ or exp Intensive Care/ or exp Intensive Care Units/ or (((intensive or critical) adj3 unit*) or (critical* adj3 ill*)).mp. 
5. 4 and 3
6. ((randomized controlled trial or controlled clinical trial).pt. or randomized.ab. or placebo.ab. or clinical trial.af. or randomly.ab. or trial.ti.) not (animals not (humans and animals)).sh. 
7. 6 and 5

02 Search Strategy for EMBASE <1980 to April 2014>

#1 (((Music or complementary or alternative or cognitive or behavioural) adj3 therap*) or (imagery or massage or muscle relaxation or therapeutic touch or aromatherapy) or ((environmental or cognitive or behavioural or interventions or social support) adj3 intervention*) or (nighttime light or noise level* or melatonin)).ti,ab. or (sleep adj3 (promot* or help* or support* or Initiat*)).mp. or sleep.ti,ab.
#2 alternative medicine/ or music therapy/ or massage/ or muscle relaxation/ or imagery/ or cognitive therapy/ or behavior therapy/ or social support/ or physiotherapy/ or aromatherapy/ or exp sleep/
#3 #1 or #2
#4 intensive care unit/ or ((intensive or critical) adj3 unit*).ti,ab.
#5 #3 and #4
#6 (controlled study.ab. or random*.ti,ab. or trial*.ti,ab.) not (animals not (humans and animals)).sh.
#7 #5 and #6
#8 from #7 keep #1

03 Search Strategy for CINAHL via EBSCO host <1982 to July 2013>

#S1 (MH "Alternative Therapies")
#S2 (MM "Music Therapy")
#S3 (MH "Massage")
#S4 (MH "Muscle Relaxation")
#S5 (MH "Cognitive Therapy")
#S6 (MH "Behavior Therapy")
#S7 (MH "Social Support (Iowa NOC)") or (MH "Social Support Index")
#S8 (MH "Physical Therapy")
#S9 (MH "Aromatherapy")
#S10 (MH "Sleep")
#S11 AB ((Music or complementary or alternative or cognitive or behavioural) and therap*)
#S12 AB imagery or massage or muscle relaxation or therapeutic touch or aromatherapy
#S13 AB ((environmental or cognitive or behavioural or interventions or social support) and intervention*)
#S14 AB nighttime light or noise level*
#S15 AB ( (sleep and (promot* or help* or support* or Initiat*)) ) or TI sleep
#S16 #S1 or #S2 or #S3 or #S4 or #S5 or #S6 or #S7 or #S8 or #S9 or #S10 or #S11 or #S12 or #S13 or #S14 or #S15
#S17 (MM "Critical Illness") or (MM "Critically Ill Patients")
#S18 (MM "Critical Care")
#S19 (MH "Intensive Care Units")
#S20 AB ( (intensive or critical) and unit* ) or AB ( critical* and ill* )
#S21 #S17 or #S18 or #S19 or #S20
#S22 #S16 and #S21
#S23 (MM "Random Assignment")
#S24 AB random* or AB controlled trial*
#S25 #S23 or #S24
#S26 #S22 and #S25

Appendix 4. Search strategy for ISI Web of Science

#1 Topic=(Critical Illness or Critical Care or Intensive Care or Intensive Care Units or critical* ill*)
#2 Topic=(Sleep or sleep promot* or help* or support* or Initiat*)
#3 Topic=(randomized controlled trial or controlled clinical trial or placebo or clinical trial or randomly or trial)
#4 Topic=(Music or complementary or alternative or cognitive or behavioural therap* or imagery or massage or muscle relaxation or therapeutic touch or ventilation or aromatherapy or environmental or cognitive or behavioural or interventions or social support intervention* or nighttime light or noise level*)
$5 #4 AND #3 AND #2 AND #1

Appendix 5. Data Extraction Form

CARG 200 Non‐pharmacological interventions for sleep promotion in intensive care unit

Data Extraction Form

Reviewer ________________________

Reference number ________________

Study ID ________________________

Date of review ___________________

Study eligibility form

I f issue relates to selective reporting (i.e. when authors may have taken measurements for particular outcomes, but not reported these), reviewers should contact trialists for information on possible non‐reported outcomes & reasons for exclusion from publication. Study should be listed in 'Studies awaiting assessment' until clarified. If no clarification is received after three attempts, study should then be excluded. 

Final decision: Include □ Unclear □ Exclude □

 
Freehand space for comments on study design and treatment:

References to trial

Check other references identified in searches. If there are further references to this trial link the papers now and list below. All references to a trial should be linked under one Study ID in RevMan.

Participants and trial characteristics

Methodological quality

Were withdrawals described? Yes □ No □ not clear □

Discuss if appropriate

Data extraction

Freehand space for writing actions such as contact with study authors and changes

References to other trials 

Notes

Edited (no change to conclusions)

Data and analyses

Comparison 1

Ear plugs or eye mask versus usual care or both

Characteristics of studies

Characteristics of included studies [ordered by study ID]

Characteristics of excluded studies [ordered by study ID]

Characteristics of studies awaiting assessment [ordered by study ID]

Characteristics of ongoing studies [ordered by study ID]

Differences between protocol and review

1. In the protocol (Hu 2010), we planned to synthesize data using Review Manager software (RevMan 5); in the review, we used RevMan 5.3.

2. At least one o utcome listed under 'Criteria for considering studies for this review' was a criteria for including studies; this was not pre‐specified in the protocol.

3. In the protocol, we originally specified the inclusion of studies of critically ill adult patients who were admitted to the intensive or critical care units, where the length of intensive care unit (ICU) stay was more than 48 hours, having stable hemodynamic status without any sedative, narcotic drugs administered in the 24 hours prior to recruitment. During the review, we did not restrict the length of ICU stay because several trials included participants where the expected length of stay in the ICU was more than 24 hours.

4. We added two additional authors to the team: Xin Huining was responsible for entering data, and David Evans was responsible for checking the review against peer review comments and revising the review for language.

5. We changed the Allied and Complementary Medicine Database (AMED) to Alt HealthWatch from May 2011, because we were then unable to access the AMED database.

6. We had planned to include the following additional treatment comparisons, but there were insufficient trials to do so, or the available trials had important clinical heterogeneity among them: acupressure versus other interventions or placebo, aromatherapy versus other interventions or placebo, back massage versus other interventions or placebo, foot baths versus other interventions or placebo, relaxation and imagery versus other interventions or placebo, foot massage versus other interventions or placebo, using sound masking versus other interventions or placebo, and social support intervention versus other interventions or placebo. Therefore, we included trials comparing these interventions with other therapies or placebo in the narrative but not the meta‐analysis of this review.

7. Considering the presence of carry‐over, we had planned to analyse the data from only the first period in cross‐over RCTs. However, only two cross‐over RCTs reported data from the first period and the cross‐over period, whereas the remaining studies only reported the whole period data. Thus, we took the decision to exclude cross‐over studies from the meta‐analyses.

8. We planned to test the robustness of the evidence by sensitivity analyses according to sequence generation, allocation concealment (adequate or unclear or inadequate), and blinding (adequate or unclear or inadequate or not performed). We intended to compare the fixed‐effect model results with the random‐effects model results. We planned to undertake sensitivity analyses to examine the effects of excluding study subgroups. None of these actions were performed due to the heterogenous nature of the included studies.

9. We planned to perform subgroup analyses. However, as we only pooled two studies for each meta‐analysis in this review, subgroup analyses were not performed,

10. We replaced the outcome of arousal index with the sleep fragmentation index in the 'Summary of findings' table as the majority of trials reported the sleep fragmentation index and did not report the arousal index.

11. We originally included the following statements in the protocol but did not implement these plans during the review owing to the types of data available; we removed these methods from the current methods section, but they may be relevant to future updates.

• • Effect measures for dichotomous outcomes: we will calculate odds ratios (ORs) and 95% confidence intervals (CIs) for dichotomous outcomes.

  • Dealing with missing data: we will extract data regarding intention‐to‐treat (ITT). If the researchers did not perform ITT and participants lost to follow up are less than 20%, but sufficient raw data are available, we will conduct an ITT analysis prior to data entry into RevMan 5.0. If more than 20% of the data are missing from the study, we will exclude the study from the meta‐analysis and perform an available case analysis.

  • 'Summary of findings' tables: we intend to include seven outcomes, such as sleep efficiency index; rapid eye movement (REM) sleep time; REM sleep latency; arousal index; mortality; length of ICU stay; and risk of delirium during ICU stay.

Contributions of authors

Conceiving the review: Rong‐Fang Hu (HRF).
Co‐ordinating the review: HRF.
Undertaking manual searches: HRF.
Screening search results: HRF and Xiao Y Chen (CXY).
Organizing retrieval of papers: HRF and CXY.
Screening retrieved papers against inclusion criteria: HRF.
Appraising quality of papers: HRF and Yueping Li (LYP).
Extracting data from papers: HRF and CXY.
Writing to authors of papers for additional information: HRF.
Providing additional data about papers: HRF.
Obtaining and screening data on unpublished studies: Xiao‐Ying Jiang (JXY).
Data management for the review: HRF and JXY.
Entering data into Review Manager (1): HRF.
RevMan statistical data: HRF and Junmin Chen (CJM).
Other statistical analysis not using RevMan: LYP.
Double entry of data: (data entered by person one: HRF; data entered by person two: Xin Huining (XHN)).
Interpretation of data: HRF, CJM, and Zhiyong Zeng (ZZY).
Statistical inferences: LYP.
Writing the review: HRF and David Evans (DE).
Guarantor for the review (one author): HRF.
Person responsible for reading and checking review before submission: CJM, HRF, and DE

Sources of support

Internal sources

• School of Nursing, Fujian Medical University, China.

External sources

• National Natural Science Funds of China (Grant No. 81201500) and Ministry of Education's Humanities and Social Sciences Project (No.11YJC190008), China.

Declarations of interest

Rong‐Fang Hu: nothing to declare.
Xiao‐Ying Jiang: nothing to declare.
Junmin Chen: nothing to declare.
Zhiyong Zeng: nothing to declare.
Xiao Y Chen: nothing to declare.
Yueping Li: nothing to declare.
Xin Huining: nothing to declare.
David Evans: nothing to declare.

References

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NCT01343095 {published data only}

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NCT01580956 {unpublished data only}

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NCT01607723 {unpublished data only}

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IRCT2013030912749N1 {unpublished data only}

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NCT00638339 {unpublished data only}

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NCT01082016 {unpublished data only}

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NCT01276652 {unpublished data only}

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NCT01284140 {unpublished data only}

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NCT01523938 {unpublished data only}

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NCT01727375 {unpublished data only}

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NCT02095496 {unpublished data only}

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