Although sleep is important for healing, sleep deprivation is a major concern for patients in hospitals. The purpose of this review is to consolidate the observational and interventional studies that have been done to understand exogenous, non-pharmacological strategies for improving sleep in hospitals. We searched Medline, CINAHL, PsycINFO and the Web of Science databases for peer-reviewed articles published between 1970 and 2015 in English. A title review of 13,113 articles from four databases resulted in 783 articles that were further culled to 277 based on a review of the abstracts. The net result after reading the articles and a hand search was 42 articles. From each article we recorded the independent variables, methods used for measuring sleep and specific sleep outcomes reported. Results of data synthesis Noise is a modifiable cause of some sleep disruptions in hospitals, and when reduced can lead to more sleep. Earplugs and eye masks may help, but changing the sound and light environment is more effective. Calming music in the evening has been shown to be effective as well as daytime bright light exposure. Nursing care activities cause sleep disruption, but efforts at limiting interventions have not been demonstrated to improve sleep conditions. The research is hard to consolidate due to the multitude of independent variables and outcome metrics, but overall points to the potential for making meaningful improvements in the quality of patient sleep.
Sleep, hospital environment, inpatients, sleep deprivation, sound, light
This paper reviews studies of exogenous (i.e. non-pharmacological) strategies for improving the nighttime sleep of patients in hospitals. The significance of sleep disruption in hospitals has been addressed in other papers, as have the negative consequences for patient outcomes [1–6]. The authors identified all research papers on sleep improvement studies in hospitals, as well as studies that sought to make correlations between existing conditions and sleep outcomes, evaluated the evidence to support the efficacy of those interventions and provide recommendations for quality improvement initiatives.
Sleep is vital for maintaining health and healing, and is essential for a quality hospital experience. Growth hormones, responsible for physical repair and renewal, are primarily secreted during sleep [7, 8]. Sleep deprivation has serious impacts including decreased pain tolerance, increased immunosuppression, delayed healing, confusion, disorientation and delusions [7], higher blood pressure [9] and higher heart rate [10]. Longer term impacts include decreased performance on activities of daily living [4, 5], lower physical functioning after release from the hospital [11, 12], higher overall mortality 1-year post discharge [7] and incidence of delirium [13, 14]. Because of these varied negative impacts, hospitals have tried different improvement practices to enhance the quality of patient sleep in their facilities.
A brief description of sleep helps explain how it can be disrupted or promoted. During sleep we are no longer conscious of our environment, yet the brain continues to receive sensory information monitoring the environment for threats, filtering out and ignoring what it can and only attending to potentially threatening stimuli [15]. This subconscious vigilance is important for protecting us from danger, but makes sleep fragile in high sensory environments like the patient room. The arousal threshold is highest during the most restorative phase of sleep, slow wave sleep, which is decreased in critically ill patients [3, 16, 17], suggesting that patients spend more time at night with a lower arousal threshold.
Given that sleep is non-responsiveness to sensory stimuli from the environment, sleep can be supported through three basic mechanisms: reducing the stimuli themselves; interrupting the transmission of sensory stimuli from the environment to the receiver; or reducing the brain's attention to the stimuli. We call the first group ‘Environmental’ because it entails changing the environment to eliminate or minimize stimuli. The next category we call ‘Intermediate’ because it operates as a barrier between the environment and the internal conditions through simple devices (earplugs, eye masks) that dampen the reception of environmental stimuli by the internal system. The final category we call ‘Internal’ because these strategies change the internal receptiveness to sleep, and include relaxation strategies such as aromatherapy, massage, and daytime exposure to light to entrain the circadian rhythm.
If sleep is a state of disconnection with the environment, then how can hospitals support and encourage sleep? What quality improvement practices have been demonstrated to work and should be replicated? This review discusses the research in each mode of application (environmental, intermediate and internal) and then the programs that used multiple modalities to improve sleep. Regarding the sources of sleep disruptions, this review specifically focuses on sleep disruptions caused by environmental factors and does not explore sleep disruptions caused by pain, nor arousals caused by sleep-disordered breathing and ventilators.
Methods
We searched Medline, CINAHL, PsycINFO and Web of Science databases for articles published in peer-reviewed journals or conference proceedings, between 1970 and 2015 in English using combinations of three sets (intervention, outcome, setting) of keywords, listed in Table 1. The resulting set of articles, were filtered to include only those studying adult hospitalized patients in medical/surgical or intensive care inpatient units, and excluding populations with specific psychological conditions such as dementia because of their unique sleep architecture. Next, we performed a quality screening to identify articles reporting randomized controlled trials, quasi-randomized trials, before-and-after studies, cohort and observational studies that looked at the predictive power of hospital conditions on sleep.
Table 1
Search terms and results for each database
| Light | Medline | (MM ‘Light+’) OR (MM ‘Lighting’) OR (MM ‘Phototherapy+’) | (MM ‘Sleep+’) OR (MM ‘Sleep Disorders+’) | (MM ‘Inpatients’) OR (MM ‘Critical Care+’) OR (MM ‘Intensive Care Units+’) | 10 |
| CINAHL | (MM ‘Light+’) OR (MM ‘Lighting’) OR (MM ‘Photography+’) | (MM ‘Sleep+’) OR (MM ‘Sleep Disorders+’) | (MM ‘Inpatients’) OR (MM ‘Critical Care+’) OR (MM ‘Acute Care’) OR (MM ‘Medical-Surgical Nursing+’) OR (MM ‘Intensive Care Units+’) | 5 | |
| PsycINFO | MM ‘Illumination’ OR MM ‘Luminance’ OR DE ‘Light Adaptation’ OR DE ‘Dark Adaptation’ OR MM ‘Phototherapy’ | MM ‘Sleep’ OR MM ‘Napping’ OR MM ‘REM Sleep’ OR MM ‘Sleep Deprivation’ OR MM ‘Sleep Disorders’ OR MM ‘Insomnia’ OR DE ‘Biological Rhythms’ OR MM ‘Human Biological Rhythms’ OR MM ‘Sleep Wake Cycle’ OR MM ‘Consciousness States’ OR MM ‘Sleepiness’ OR MM ‘Wakefulness’ OR MM ‘Polysomnography’ OR MM ‘Sleep Treatment’ OR MM ‘CLOCK Gene’ | MM ‘Treatment Facilities’ OR MM ‘Hospitals’ OR MM ‘Intensive Care’ | 4 | |
| Web of Science | Light* OR Illumination OR Luminance OR Luminescence OR Dark* OR Phototherapy | Sleep* OR ‘Circadian rhythm’ OR Insomnia OR Nap OR ‘Biological Rhythm’ OR Wake* OR ‘CLOCK Gene’ | Inpatient OR ‘Critical care’ OR ‘Intensive care’ OR ‘Acute care’ OR MedSurg OR ‘Medical Surgical’ OR Perioperative OR Postoperative OR Hospital* OR ‘Health facility’ | 703 | |
| Noise | Medline | (MM ‘Sound+’) OR (MM ‘Voice+’) OR (MM ‘Acoustics+’) | (MM ‘Sleep+’) OR (MM ‘Sleep Disorders+’) | (MM ‘Inpatients’) OR (MM ‘Critical Care+’) OR (MM ‘Intensive Care Units+’) | 33 |
| CINAHL | (MM ‘Sound+’) OR (MM ‘Voice+’) OR (MM ‘Acoustics+’) | (MM ‘Sleep+’) OR (MM ‘Sleep Disorders+’) | (MM ‘Inpatients’) OR (MM ‘Critical Care+’) OR (MM ‘Acute Care’) OR (MM ‘Medical-Surgical Nursing+’) OR (MM ‘Intensive Care Units+’) | 33 | |
| PsycINFO | MM ‘Auditory Stimulation’ OR DE ‘Loudness’ OR DE ‘Noise Levels (Work Areas)’ OR MM ‘Acoustics’ OR MM ‘Voice’ | MM ‘Sleep’ OR MM ‘Napping’ OR MM ‘REM Sleep’ OR MM ‘Sleep Deprivation’ OR MM ‘Sleep Disorders’ OR MM ‘Insomnia’ OR DE ‘Biological Rhythms’ OR MM ‘Human Biological Rhythms’ OR MM ‘Sleep Wake Cycle’ OR MM ‘Consciousness States’ OR MM ‘Sleepiness’ OR MM ‘Wakefulness’ OR MM ‘Polysomnography’ OR MM ‘Sleep Treatment’ OR MM ‘CLOCK Gene’ | MM ‘Treatment Facilities’ OR MM ‘Hospitals’ OR MM ‘Intensive Care’ | 1 | |
| Web of Science | Sound OR Noise* OR Acoustic* OR Voice OR loudness | Sleep* OR ‘Circadian rhythm’ OR Insomnia OR Nap OR ‘Biological Rhythm’ OR Wake* OR ‘CLOCK Gene’ | Inpatient OR ‘Critical care’ OR ‘Intensive care’ OR ‘Acute care’ OR MedSurg OR ‘Medical Surgical’ OR Perioperative OR Postoperative OR Hospital* OR ‘Health facility’ | 784 | |
| Temperature/air | Medline | (MM ‘Temperature+’) OR (MM ‘Air+’) OR (MM ‘Environment, Controlled+’) | (MM ‘Sleep+’) OR (MM ‘Sleep Disorders+’) | (MM ‘Inpatients’) OR (MM ‘Critical Care+’) OR (MM ‘Intensive Care Units+’) | 9 |
| CINAHL | (MM ‘Temperature+’) OR (MM ‘Comfort’) OR (MM ‘Air+’) OR (MM ‘Environment, Controlled+’) | (MM ‘Sleep+’) OR (MM ‘Sleep Disorders+’) | (MM ‘Inpatients’) OR (MM ‘Critical Care+’) OR (MM ‘Acute Care’) OR (MM ‘Medical-Surgical Nursing+’) OR (MM ‘Intensive Care Units+’) | 4 | |
| PsycINFO | MM ‘Temperature Perception’ OR MM ‘Thermal Acclimatization’ OR MM ‘Temperature Effects’ OR MM ‘Cold Effects’ OR MM ‘Heat Effects’ OR MM ‘Physical Comfort’ | MM ‘Sleep’ OR MM ‘Napping’ OR MM ‘REM Sleep’ OR MM ‘Sleep Deprivation’ OR MM ‘Sleep Disorders’ OR MM ‘Insomnia’ OR DE ‘Biological Rhythms’ OR MM ‘Human Biological Rhythms’ OR MM ‘Sleep Wake Cycle’ OR MM ‘Consciousness States’ OR MM ‘Sleepiness’ OR MM ‘Wakefulness’ OR MM ‘Polysomnography’ OR MM ‘Sleep Treatment’ OR MM ‘CLOCK Gene’ | MM ‘Treatment Facilities’ OR MM ‘Hospitals’ OR MM ‘Intensive Care’ | ||
| Web of Science | Temperature OR Heat* OR thermal OR Comfort OR ‘Air Velocity’ OR ‘Air Conditioning’ OR Humidity OR Ventilation OR ‘Air Flow’ OR ‘Air Quality’ OR HVAC | Sleep* OR ‘Circadian rhythm’ OR Insomnia OR Nap OR ‘Biological Rhythm’ OR Wake* OR ‘CLOCK Gene’ | Inpatient OR ‘Critical care’ OR ‘Intensive care’ OR ‘Acute care’ OR MedSurg OR ‘Medical Surgical’ OR Perioperative OR Postoperative OR Hospital* OR ‘Health facility’ | 1690 | |
| Architecture/interior design/furniture | Medline | (MM ‘Architecture as Topic+’) OR (MM ‘Environment Design’) | (MM ‘Sleep+’) OR (MM ‘Sleep Disorders+’) | (MM ‘Inpatients’) OR (MM ‘Critical Care+’) OR (MM ‘Intensive Care Units+’) | 4 |
| CINAHL | (MM ‘Architecture+’) | (MM ‘Sleep+’) OR (MM ‘Sleep Disorders+’) | (MM ‘Inpatients’) OR (MM ‘Critical Care+’) OR (MM ‘Acute Care’) OR (MM ‘Medical-Surgical Nursing+’) OR (MM ‘Intensive Care Units+’) | 1 | |
| PsycINFO | MM ‘Furniture’ OR MM ‘Architecture’ OR MM ‘Interior Design’ OR MM ‘Hospital Environment’ | MM ‘Sleep’ OR MM ‘Napping’ OR MM ‘REM Sleep’ OR MM ‘Sleep Deprivation’ OR MM ‘Sleep Disorders’ OR MM ‘Insomnia’ OR DE ‘Biological Rhythms’ OR MM ‘Human Biological Rhythms’ OR MM ‘Sleep Wake Cycle’ OR MM ‘Consciousness States’ OR MM ‘Sleepiness’ OR MM ‘Wakefulness’ OR MM ‘Polysomnography’ OR MM ‘Sleep Treatment’ OR MM ‘CLOCK Gene’ | MM ‘Treatment Facilities’ OR MM ‘Hospitals’ OR MM ‘Intensive Care’ | 1 | |
| Web of Science | Architecture OR Furniture OR Furnishing OR Floor* OR ‘Interior Design’ OR ‘Hospital Design’ OR ‘Facility Environment’ OR ‘Hospital environment’ OR ‘Healthcare Environment’ | Sleep* OR ‘Circadian rhythm’ OR Insomnia OR Nap OR ‘Biological Rhythm’ OR Wake* OR ‘CLOCK Gene’ | Inpatient OR ‘Critical care’ OR ‘Intensive care’ OR ‘Acute care’ OR MedSurg OR ‘Medical Surgical’ OR Perioperative OR Postoperative OR Hospital* OR ‘Health facility’ | 488 | |
| Medical equipment and supplies | Medline | (MM ‘Equipment and Supplies+’) | (MM ‘Sleep+’) OR (MM ‘Sleep Disorders+’) | (MM ‘Inpatients’) OR (MM ‘Critical Care+’) OR (MM ‘Intensive Care Units+’) | 4 |
| CINAHL | (MM ‘Equipment and Supplies+’) | (MM ‘Sleep+’) OR (MM ‘Sleep Disorders+’) | (MM ‘Inpatients’) OR (MM ‘Critical Care+’) OR (MM ‘Acute Care’) OR (MM ‘Medical-Surgical Nursing+’) OR (MM ‘Intensive Care Units+’) | 8 | |
| PsycINFO | ’Medical Therapeutic Devices’ OR MM ‘Apparatus’ OR MM ‘Mobility Aids’ OR MM ‘Assistive Technology’ | MM ‘Sleep’ OR MM ‘Napping’ OR MM ‘REM Sleep’ OR MM ‘Sleep Deprivation’ OR MM ‘Sleep Disorders’ OR MM ‘Insomnia’ OR DE ‘Biological Rhythms’ OR MM ‘Human Biological Rhythms’ OR MM ‘Sleep Wake Cycle’ OR MM ‘Consciousness States’ OR MM ‘Sleepiness’ OR MM ‘Wakefulness’ OR MM ‘Polysomnography’ OR MM ‘Sleep Treatment’ OR MM ‘CLOCK Gene’ | MM ‘Treatment Facilities’ OR MM ‘Hospitals’ OR MM ‘Intensive Care’ | 0 | |
| Web of Science | Equipment OR Device OR Apparatus OR Supply OR Alarm OR Bed OR Technology | Sleep* OR ‘Circadian rhythm’ OR Insomnia OR Nap OR ‘Biological Rhythm’ OR Wake* OR ‘CLOCK Gene’ | Inpatient OR ‘Critical care’ OR ‘Intensive care’ OR ‘Acute care’ OR MedSurg OR ‘Medical Surgical’ OR Perioperative OR Postoperative OR Hospital* OR ‘Health facility’ | 1937 | |
| Nursing care | Medline | (MM ‘Patient Care Management+’) OR (MM ‘Clinical Protocols+’) OR (MM ‘Hospital Administration+’) OR (MM ‘Health Personnel+’) OR (MM ‘Patient Care+’) OR (MM ‘Diagnostic Techniques and Procedures+’) OR (MM ‘Visitors to Patients’) | (MM ‘Sleep+’) OR (MM ‘Sleep Disorders+’) | (MM ‘Inpatients’) OR (MM ‘Critical Care+’) OR (MM ‘Intensive Care Units+’) | 159 |
| CINAHL | (MM ‘Patient Care+’) OR (MM ‘Health Services Administration+’) OR (MM ‘Health Personnel+’) OR (MM ‘Caregivers’) OR (MM ‘Diagnosis+’) OR (MM ‘Visitors to Patients’) | (MM ‘Sleep+’) OR (MM ‘Sleep Disorders+’) | (MM ‘Inpatients’) OR (MM ‘Critical Care+’) OR (MM ‘Acute Care’) OR (MM ‘Medical-Surgical Nursing+’) OR (MM ‘Intensive Care Units+’) | 152 | |
| PsycINFO | MM ‘Treatment Planning’ OR MM ‘Therapeutic Processes’ OR MM ‘Health Care Policy’ OR MM ‘Health Care Administration’ OR MM ‘Hospital Administration’ OR MM ‘Clinicians’ OR MM ‘Health Personnel’ OR MM ‘Medical Personnel’ OR MM ‘Nurses’ OR MM ‘Physicians’ OR MM ‘Caregivers’ OR MM ‘Diagnosis’ OR MM ‘Medical Diagnosis’ OR MM ‘Treatment’ OR MM ‘Health Care Services’ OR MM ‘Treatment Guidelines’ OR MM ‘Institution Visitation’ | MM ‘Sleep’ OR MM ‘Napping’ OR MM ‘REM Sleep’ OR MM ‘Sleep Deprivation’ OR MM ‘Sleep Disorders’ OR MM ‘Insomnia’ OR DE ‘Biological Rhythms’ OR MM ‘Human Biological Rhythms’ OR MM ‘Sleep Wake Cycle’ OR MM ‘Consciousness States’ OR MM ‘Sleepiness’ OR MM ‘Wakefulness’ OR MM ‘Polysomnography’ OR MM ‘Sleep Treatment’ OR MM ‘CLOCK Gene’ | MM ‘Treatment Facilities’ OR MM ‘Hospitals’ OR MM ‘Intensive Care’ | 18 | |
| Web of Science | ’Care process’ OR ‘Clinical process’ OR Nursing* OR ‘Care plan’ OR ‘Patient care’ OR Organization OR Administration OR Policy OR Protocol OR Staff OR Personnel OR Nurse OR Caregiver OR Physician OR ‘Care time’ OR ‘Care episode’ OR ‘Care activity’ OR ‘Patient transfer’ OR Diagnosis OR Diagnostic OR ‘Physical exam’ OR ‘Vital Sign’ OR ‘Wound Assessment’ OR ‘Skin Test’ OR phlebotomy OR Visitor OR Visitation | Sleep* OR ‘Circadian rhythm’ OR Insomnia OR Nap OR ‘Biological Rhythm’ OR Wake* OR ‘CLOCK Gene’ | Inpatient OR ‘Critical care’ OR ‘Intensive care’ OR ‘Acute care’ OR MedSurg OR ‘Medical Surgical’ OR Perioperative OR Postoperative OR Hospital* OR ‘Health facility’ | 18 636 | |
| Total | 24 688 | ||||
| After removing duplicates | 13 113 |
Study selection
The initial search retrieved 13 113 articles from four databases for which we excluded 12 330 articles based on a review of the titles. A review of the abstracts for the remaining 783 articles resulted in 277 articles that warranted closer examination, and of these only 40 met all our criteria. Two papers published subsequently were discovered through hand searching. Fig. 1 shows the process of inclusion/exclusion.
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Literature review flow diagram.
Data extraction
Each article was reviewed by both authors, and key information about the variables, setting, population and findings was abstracted into tables. Additionally, articles were labeled by the modality of intervention (environmental, internal, intermediate, and multi-modal) and the way in which sleep was measured (polysomnography, self-report, observation, actigraphy). These details are captured in Tables 2–5; the specific strategies used by each are listed in Table 6.
Table 2
Summary of environmental references
| Aaron, Carlisle, Carskadon, Meyer, Hill, & Millman (1996) | Environmental | Noise | Observational | Polysomnography | Intermediated respiratory care unit (IRCU) | 66.8(2.8) | Number of arousals from sleep |
| Adib-Hajbaghery, Izadi-Avanji & Akbari (2012) | Environmental | Noise; Light; Temperature | Observational | Self-report | Medical surgical wards | 71.8(5.6) | Overall quality of sleep scores |
| Bihari, McEvoy, Matheson, Kim, Woodman, & Bersten (2012) | Environmental | Noise; Light; Nursing activity | Observational | Self-report | Medical surgical ICU | 63.2(16.7) | Sleep quality; daytime sleepiness |
| Elliott, McKinley, Cistulli, & Fien (2013) | Environmental | Noise | Observational | Self-report; Polysomnography | Adult ICU | 60.13(20.2) | Total sleep time; Sleep stages; Duration per stage; Duration of sleep episode |
| Elliott, Rai, & McKinley (2014) | Environmental | Noise; Light | Observational | Self-report; Polysomnography | Adult ICU | Not reported (patients older than 17 years) | Total sleep time; Number of sleep periods |
| Faraklas, Holt, Tran, Lin, Saffle, & Cochran (2013) | Environmental | Sleep hygiene protocol | Experimental | Self-report | Adult burn trauma ICU | Pre-treatment group = 41(27–58); Post-treatment group = 49(33–62) | Sleep quality |
| Freedman, Gazendam, Levan, Pack, & Schwab (2001) | Environmental | Noise | Observational | Polysomnography | Mechanically ventilated patients in medical ICU | 61(16) | Arousals from sleep specifically due to noise |
| Gabor, Cooper, Crombach, Lee, Kadikar, Bettger, & Hanly (2003) | Environmental | Noise; Nursing activity | Observational | Self-report; Polysomnography | Mechanically ventilated patients in critical care unit | 56.7(19.2) | Arousals from sleep; Arousal or awakenings causes by noise; Arousals or awakenings caused by patient care activities |
| Gardner, Collins, Osborne, Henderson, & Eastwood (2009) | Environmental | Quiet time(Noise; Light; Care activity) | Experimental | Observation; Self-report | Orthopedic wards | Experimental group = 56.4(19.1); Control group = 50.5(19.4) | Afternoon sleep; overall sleepiness |
| Li, Wang, Vivienne Wu, Liang, & Tung (2011). | Environmental | Noise; Light Nursing care | Experimental | Self-report | Surgical ICU | 50 (2.6) | Sleep quality |
| Maidl, Leske, & Garcia (2014) | Environmental | Quiet time (Light, Noise, Care activities) | Experimental | Self-report; observation | Adult Neuroscience/Cardiovascular ICU | 61 | Sleep quality |
| Missildine, Bergstrom, Meininger, Richards, & Foreman (2010) | Environmental | Noise; Light | Observational | Self-report; actigraphy | Medical units | 79 | Total sleep time; Sleep efficiency; Duration of longest sleep period; number/length of wake episodes; Sleep quality |
| Norton, Flood, Brittin, & Miles, (2015) | Environmental | Noise; Light, Temperature; Aroma | Experimental | Self-report | Medical, surgical, emergency, and high-dependency | Not reported | Overall sleep quality; Disturbance from noise, temperature, light, smell and routine checks |
| Olson, Borel, Laskowitz, Moore, & McConnell (2001) | Environmental | Quiet time(Noise; Light; Care activity) | Experimental | Observation | Neuocritical care | 51 for intervention; 48 for control | Sleep state (Asleep, awake or unable to determine) |
| Park, Yoo, Cho, Kim, Jeong, & Ha (2014) | Environmental | Noise | Observational | Self-report | Internal medicine | 60 (14.8) | Sleep quality |
| Patel, Baldwin, Bunting, & Laha (2014) | Environmental | Noise; Light; Nursing care | Experimental | Self-report | ICU | Pre-treatment group = 60(13.7); Post-treatment group = 60.6(16.3) | Sleep efficiency index; daytime sleepiness; time asleep at night |
| Pattison & Robertson (1996) | Environment | Layout | Observational | Self-report | Post-operative gynecology | 43.6 for patients in Bay layout; 47.1 for Nightingale layout | Sleep quality |
| Pimentel-Souza, Carvalho, & Siqueira (1996) | Environmental | Noise | Observational | Self-report | Internal medicine | 35.6 (17–60) | Sleep quality |
| Sheely (1996) | Environmental | Nursing care | Observational | Self-report | Cancer | 48 | Total sleep time; Sleep quality |
| Valham, Sahlin, Stenlund, & Franklin (2012) | Environmental | Temperature | Experimental | Self-report; Polysomnography | Sleep apnea | 59.6 | Apnea-hypopnea index; Sleepiness; Sleep stage; Total sleep time; Sleep efficiency |
Table 3
Summary of intermediate references
| Jones & Dawson (2012) | Intermediate | Eye masks & ear plugs | Experimental | Self-report | ICU | Pre-treatment group = 58.07(18.44); Post-intervention group = 56.34(18.41) | Sleep quantity; Sleep quality |
| Le Guen, Nicolas-Robin, Lebard, Arnulf, & Langeron (2014) | Intermediate | Eye masks & ear plugs | Experimental | Observation; Self-report; Actigraphy | Post-anesthesia care unit | control group = 59 (3); intervention group = 62 (3) | Sleep quality; Need for a nap; Sleep length; Sleep efficiency |
| Richardson, Allsop, Coghill, & Turnoc (2007) | Intermediate | Eye masks & ear plugs | Experimental | Self-report | Cardiothoracic ICU | Not reported (patients older than 18 years) | Self-reported sleep experience |
| Scotto, McClusky, Spillan, & Kimme (2009) | Intermediate | Earplugs | Experimental | Self-report | Critical care unit | 63 | Sleep quality |
| Yazdannik, Zareie, Hasanpour, & Kashefi (2014) | Intermediate | Eye masks & ear plugs | Experimental | Self-report | ICU | Not reported (patients older than 18 years) | Sleep effectiveness; Sleep disturbance |
Table 4
Summary of internal references
| Bano, Chiaromanni, Corrias, Turco, De Rui, Amodio, et al. (2014) | Internal | Light | Observational | Self-report | Internal medicine | Mean = 76(11) | Sleep quality |
| Cho, Min, Hur, & Lee (2013) | Internal | Aroma | Experimental | Self-report | Ischemic heart diseases | Not reported | Sleep quality |
| Giménez, Geerdinck, Versteylen, Leffers, Meekes, Herremans, et al. (2011) | Internal | Light | Experimental | Actigraphy | Cardiology | 65.9(14.9) | Total sleep duration; Sleep onset latency; Sleep efficiency |
| Hajibagheri, Babaii, & Adib-Hajbaghery (2014) | Internal | Aroma | Experimental | Self-report | Coronary care unit | Experimental group = 61.40(11.64); Control group = 63.9(10.23) | Overall sleep quality, sleep latency, sleep duration, sleep efficiency, sleep disturbance |
| Chong, Tan, Tay, Wong, & Ancoli-Israel (2013) | Internal | Light | Experimental | Observation | Delirious geriatric | 84.2 | Total sleep time; Number of awakenings; Number of sleep bouts (SB); Length of each bout |
| Richards (1998) | Internal | Massage; Guided relaxation | Experimental | Polysomnography | Coronary care unit | 65.8 (range, 55–79) | Sleep efficiency index |
| Richardson (2003) | Internal | Relaxation; Guided imagery | Experimental | Self-report | Critical care unit | 58.4 (14.3) | Sleep quality |
| Ryu, Park, & Park (2012) | Internal | Music | Experimental | Self-report | Cardiac ICU | 61.2 | Sleep quality; Sleep quantity |
| Su, Lai, Chang, Yiin, Perng, & Chen (2013) | Internal | Music | Experimental | Self-report; Polysomnography | Medical ICU isolation | 61.68 | Sleep quality; Total sleep time; sleep efficiency; Sleep onset latency; Percentages of stages N1, N2, N3, and rapid eye movement (REM) sleep |
| Wakamura & Tokura (2001) | Internal | Light | Experimental | Actigraphy | Cardiac | 67 (range 57–77) | Bedtime; Get up time; Time in bed; Sleep start; Sleep end; Actual awake time; Assumed sleep; Actual sleep time; Immobile minutes; Melatonin levels |
| Yang, Choi, Ko, Joe, Han, & Kim (2012) | Internal | Light | Experimental | Observation | Delirious medical surgical | Control group = 71.8; Treatment group = 67.8 | Total sleep time; Sleep efficiency; Sleep onset latency; Number of awakenings; Wake after sleep onset; Time from wake up to rising |
| Zimmerman, Nieveen, Barnason, & Schmaderer (1996) | Internal | Music, Music video | Experimental | Self-report | Post-corornary artery bypass graft | 67 (range 37–84) | Sleep quality |
Table 5
Summary of multi-modal references
| Kamdar, King, Collop, Sakamuri, Colantuoni, Neufeld, et al. (2013) | Environmental, Intermediate, Internal | Sleep hygiene protocol | Experimental | Observation; Self-report | Medical ICU | ICU evaluation: baseline = 54(43–63), Sleep QI = 54(44–66); Post-ICU evaluation: baseline = 53(41–61), sleep QI = 54(34-62) | Sleep depth; Sleep onset latency; Number of awakenings; Sleep efficiency; Sleep quality |
| LaReau, Benson, Watcharotone, & Manguba (2008) | Environmental, Internal | Sleep hygiene protocol | Experimental | Observation; Self-report | Adult medical | 79.6(7.78) | Hours of sleep; Number of awakenings; Sleep quality; Use of sleep medication |
| Spence, Murray, Tang, Butler, & Albert (2011) | Environmental, Intermediate, Internal | Multifactorial | Observational | Self-report | Cardiac | 61 | Prevention or disruption of sleep |
| Thomas, Salas, Gamaldo, Chik, Huffman, Rasquinha, & Hoesch (2012) | Environmental, Internal | Multifactorial | Experimental | Self-report | neurology/ neurosurgery | Phase 1 = 49(1); Phase 2 = 43(3); Phase 3 = 46(3) | Difficulty sleeping; Sleep onset latency; Number of awakenings; Hours of sleep |
| Topf & Thompson (2001) | Environmental, Internal | Noise, Bed, Pain, Anxiety | Observational | Self-report | Postoperative Cardiac | 62 | Sleep effectiveness; Sleep disturbance |
Table 6
Detailed strategies employed by experimental studies
| Limiting visits | Limiting treatment | Lower voices | Closing doors | Decreasing alarm noise/ anticipating alarms | Turning lights down/off | TV off | Early medication/Toilet | Sleep rounds | Bundling care | Afternoon quiet time | Adjusting temperature | Sleep Hygiene | Earplugs | Eye masks | Daytime Light | Aroma | Music | Guided Relaxation | Other | |
| Cho, Min, Hur, & Lee (2013) | ✔ | |||||||||||||||||||
| Faraklas, Holt, Tran, Lin, Saffle, & Cochran (2013) | ✔ | ✔ | ✔ | ✔ | ✔ | ✔ | ✔ | ✔ | ||||||||||||
| Gardner, Collins, Osborne, Henderson, & Eastwood (2009) | ✔ | ✔ | ✔ | ✔ | ✔ | ✔ | ||||||||||||||
| Giménez, Geerdinck, Versteylen, Leffers, Meekes, Herremans, et al. (2011) | ✔ | |||||||||||||||||||
| Hajibagheri, Babaii, & Adib-Hajbaghery (2014) | ✔ | |||||||||||||||||||
| Jones & Dawson (2012) | ✔ | ✔ | ||||||||||||||||||
| Chong, Tan, Tay, Wong, & Ancoli-Israel (2013) | ✔ | ✔ | ||||||||||||||||||
| Kamdar, King, Collop, Sakamuri, Colantuoni, Neufeld, et al. (2013) | ✔ | ✔ | ✔ | ✔ | ✔ | ✔ | ✔ | ✔ | Minimizing overhead pages | |||||||||||
| LaReau, Benson, Watcharotone, & Manguba (2008) | ✔ | ✔ | ✔ | ✔ | ✔ | ✔ | ||||||||||||||
| Le Guen, Nicolas-Robin, Lebard, Arnulf, & Langeron (2014) | ✔ | ✔ | ||||||||||||||||||
| Li, Wang, Vivienne Wu, Liang, & Tung (2011). | ✔ | ✔ | ✔ | ✔ | ✔ | Turn down phone volume | ||||||||||||||
| Maidl, Leske, & Garcia (2014) | ✔ | ✔ | ✔ | ✔ | ✔ | ✔ | ✔ | Repositioning | ||||||||||||
| Norton, Flood, Brittin, & Miles, (2015) | ✔ | ✔ | ✔ | ✔ | Fixing noisy equipment; phones (turning down or answering quickly) ; Soft soled shoes | |||||||||||||||
| Olson, Borel, Laskowitz, Moore, & McConnell (2001) | ✔ | ✔ | ✔ | ✔ | ✔ | Blinds closed | ||||||||||||||
| Patel, Baldwin, Bunting, & Laha (2014) | ✔ | ✔ | ✔ | ✔ | ✔ | ✔ | ✔ | |||||||||||||
| Richards (1998) | ✔ | Massage | ||||||||||||||||||
| Richardson (2003) | ✔ | |||||||||||||||||||
| Richardson, Allsop, Coghill, & Turnoc (2007) | ✔ | ✔ | ||||||||||||||||||
| Ryu, Park, & Park (2012) | ✔ | ✔ | ✔ | |||||||||||||||||
| Scotto, McClusky, Spillan, & Kimme (2009) | ✔ | |||||||||||||||||||
| Su, Lai, Chang, Yiin, Perng, & Chen (2013) | ✔ | |||||||||||||||||||
| Thomas, Salas, Gamaldo, Chik, Huffman, Rasquinha, & Hoesch (2012) | ✔ | ✔ | ✔ | ✔ | Offered blankets, warm milk, lotion, room spritzer | |||||||||||||||
| Valham, Sahlin, Stenlund, & Franklin (2012) | ✔ | |||||||||||||||||||
| Wakamura & Tokura (2001) | ✔ | |||||||||||||||||||
| Yang, Choi, Ko, Joe, Han, & Kim (2012) | ✔ | |||||||||||||||||||
| Yazdannik, Zareie, Hasanpour, & Kashefi (2014) | ✔ | ✔ | ||||||||||||||||||
| Zimmerman, Nieveen, Barnason, & Schmaderer (1996) | ✔ |
Results
General features and quality assessment
These studies vary significantly in research designs, methods, independent variables, measurement techniques, patient population and reported outcomes creating a challenge for synthesizing the data and drawing general conclusions. There were 27 experimental studies where the researchers made a change to the environment, care process or offered patients a sleep aid (earplugs, eye masks) and documented subsequent impacts on sleep. The other 15 articles described observational studies where researchers looked for correlations between existing conditions and sleep. Most of the studies evaluated the impact of intervention bundles making it difficult to assess the effectiveness of individual measures. Patient population also was variable across the selected studies with 8 studies on cardiovascular patients, 4 medical surgical patients, 15 ICU patients, 5 medical surgical patients, 3 internal medicine patients, 4 critical care patients and 3 postoperative patients. Geriatric, neuro and respiratory populations were among those studied.
Only eight studies measured sleep using polysomnography, a technique that records biophysiological changes and provides the most accurate and detailed information about sleep. Actigraphy, which measures lack of movement as a surrogate for sleep, was used in four studies. Thirty-four studies used a self-report survey tool such as the Pittsburgh Sleep Quality Index, Richards Campbell Sleep Questionnaire and Verran-Snyder-Halpern Sleep Scale to measure quality and quantity of sleep. In eight studies, a trained observer recorded sleep status. Many studies employed more than one sleep measurement methodology.
There was great variance in the sleep outcomes reported. The most common was overall sleep quality and total sleep duration. Other outcomes reported were sleep onset latency (time it takes to fall asleep), sleep efficiency (percentage of time in bed that is spent asleep), number of awakenings, number of arousals, daytime sleepiness, sleep depth and perceived disturbance of sleep. We only noted the impact on sleep, not capturing other outcomes such as sedative use or patient satisfaction.
Environmental strategies for minimizing stimuli
This category includes strategies to minimize the external stimuli (noise, light, temperature, aroma, nursing care activities) that wake patients during the night. See Table 2 for a summary of each article.
Noise
Noise is frequently cited as a major contributor to sleep disruption in hospitals. The studies of noise and sleep tend to have high quality objective data for sleep [18–21] and environmental sound levels [18–23]. Several studies found a correlation between number of sound peaks and number of arousals [18–20]. One study found that 20% of the arousals or awakenings from sleep could be attributed to sound peaks [18] and another found environmental noise explained 11.5% of the arousals and 17% of awakenings [19].
Research has found that the average noise level in hospitals is also important. In one hospital a significant dose response relationship between the self-reported sleep disturbances score and the mean noise levels was found, whereas the maximum noise level was not an indicator of sleep disturbances [22]. Patients find noise highly disruptive [21] and report feeling tired in the morning in noisier hospitals [23].
Layout
Two studies were found that evaluated the impact of hospital unit layout on sleep. One found no statistical difference in sleep in two ward layouts [24]. A second study found people slept better in private rooms compared with sleeping in an open ward [18].
Association with noise, light and sleep
Two observational studies evaluated impact of noise and light conditions in hospitals on sleep. In one study environmental conditions were significantly correlated with sleep quality; environmental noise was the most frequently reported sleep disturbing factor, although lighting conditions had a stronger negative effect on sleep quality [25]. While not significant, another study's findings trended in the same direction [26].
Noise, light and nursing care combined interventions
An observational study evaluating multiple environmental factors found that noise and nursing activities were significantly correlated with poor sleep quality [27].
Four multipronged improvement programs combining strategies to reduce nighttime disruptions from noise, light and nursing activities were evaluated. Two studies documented significant improvements in sleep quality and confirmed noise reductions [28, 29]. A third study confirmed significant reduction in noise, light and staff-patient interactions at night and found significant improvements in mean sleep efficiency index, daytime sleepiness and time asleep at night [30]. The final study showed a significant improvement in falling asleep more quickly after implementation, but found no impact on overall sleep quality [31].
Quiet time programs
Hospitals have tried designating ‘quiet times’ (typically from 2 to 4 p.m.) when lights are dimmed and staff and visitors are asked to minimize sounds. Two studies reported a positive impact on patient's likelihood of being asleep during a quiet time versus a control group but found no impact on sleep quality [32, 33]. Patients reported valuing quiet time in another study despite failing to find a significant impact on sleep [34].
Nursing care
Nighttime nursing activities are recognized as a major contributor to sleep disruption in hospitals [6, 16, 18, 35–39]. Several multifactorial studies included nursing care [28–30]. Only one study found this to be the sole factor, and reported that nighttime care activities were negatively correlated with sleep quality, but none impacted sleep quantity [40].
Ambient temperature
In the only article that studied the impact of temperature, sleep apnea researchers exposed 40 patients to different nighttime temperatures over three nights and found increased total sleep time and greater sleep efficiency on nights with the lowest temperature [41].
Summary of environment strategies
Noise and light have both been shown to be related to poor quality sleep in hospitals [25]. A direct relationship between noise in hospitals and sleep has been observed in several studies [20, 22, 23]. Hospitals have been able to reduce noise and light levels through interventions such as quiet times [32, 33]. Reducing disruptions due to nursing care activities have been included in successful multifactorial solutions [28–30], but rarely as a singular intervention [40].
Intermediate solutions for blocking external stimuli
Earplugs and eye masks offer an easy and affordable solution for improving sleep by blocking out noise and light. Five studies evaluating the impact of earplugs and eye masks in isolation were reviewed [42–46]. In one study patients with earplugs reported significant improvements in sleep depth, ease of falling asleep, satisfaction, amount, movement during sleep, and waking in the night [42]. A second study reported a significant decline in sleep quality in the control group, while the group with earplug and eye masks maintained a constant sleep quality [43]. Two other studies reported positive impacts on patient sleep quality, but provided no statistical analysis [45, 46] and another failed to find any significant impact on sleep [44].
Internal strategies for promoting sleep
There were 12 studies which used strategies for creating internal conditions to encourage sleep (see Table 4) including techniques to calm the mind through relaxation, music, aromatherapy, as well as strategies intended to support internal circadian rhythms in patients.
Relaxation
Relaxation through massage or guided imagery has not been proven to be effective in promoting sleep. A clinically meaningful (>1 h), but not statistically significant, impact on total patient sleep time was measured for a back massage program [47]. Another study that evaluated relaxation and guided imagery at bedtime found no significant difference in self-reported sleep depth or fragmentation between the intervention and control groups [48].
Music
Three studies found a significant positive impact of music on self-reported sleep quality [49–51]. Patients who were exposed to music with a nature video had better sleep quality than the group who only had a rest [49]. Another study measured significant improvement in sleep quality in an experimental group who listened to 45 min of ‘sedating’ music [50]. The final study compared patients sleeping with earphones with and without calming music and found the music to improve sleep quality and quantity [51].
Aroma
Studies have demonstrated a positive impact of aromatherapy [52, 53]. Measures of quality of sleep, such as sleep index, duration and sleep disturbance were significantly improved in one study [52]. Another study reported that sleep quality remained constant in the experimental group while declining for controls [53]. A third multifactorial study included prevention of noxious odors through closing toilet room doors as an intervention and found no improvement in sleep disturbance [28]. While the quantity of these studies are limited, the findings suggest aromatherapy may be beneficial for promoting sleep.
Daytime light
Daylight plays an important role in sleep regulation. It suppresses melatonin increasing alertness and entraining the circadian rhythm to support better sleep at night. We categorize daytime light exposure as an internal strategy because it impacts sleep as a result of a change in internal conditions. Light at night acts as an external stimulant so those studies were grouped with environmental strategies.
Elderly patients exposed to bright daytime light for a week slept longer and awoke later [54]. Delirium patients treated with a combination of morning light and antipsychotic drugs slept longer than those with just the drugs [55]. The use of bright light in the early evening was also found to be effective in increasing total sleep time and reducing awakenings for elderly patients [56].
Two studies were found that focused on the full course of lighting throughout the day as opposed to limited treatment episodes [57, 58]. In one study patients who slept near the window experienced significantly higher light levels during morning and early afternoon and reported significantly better subjective sleep quality than those sleeping far from the window [57]. An interventional study found that patients in rooms with simulated daylight fell asleep faster and slept longer with the impact of the effect increasing over their length of stay [58].
In general these studies confirm the positive impact of bright light exposure increasing total sleep time by between 27 min [54] and over an hour more [55].
Summary of internal strategies
There is strong evidence about the positive impact of music on sleep [49–51] and good foundational evidence of the potential for daytime light exposure to increase the duration of sleep [54, 55, 58]. The evidence for massage, relaxation and aromatherapy is not strong at this point, but these strategies may warrant further investigation.
Multiple modality strategies
Some of the sleep promotion studies used a combination of environmental, intermediate and internal strategies [59–64]. These were evenly split between observational [59–61] and interventional [62–64] research methods.
Two observational studies [59, 60] evaluated patient survey data on disruptive environmental and psychological factors to determine the correlations with sleep quality and satisfaction. One found that while noise and light were highly disruptive they were not significantly associated with sleep [60]. The other study found noise, unfamiliar bed, pain and anxiety to each be correlated with sleep effectiveness [59]. The third observational study documented use/presence of a defined list of sleep promotion and relaxation aids and found no correlation with self-reported sleep disturbance [61].
Three separate studies of sleep-promoting quality improvement programs (combinations of nursing, light and quiet times) failed to find any significant impact on self-reported sleep quality [62–64] despite the findings in one of the studies of a significant decrease in noise and reported disruptions caused by medication administration [64].
While it is likely that a successful sleep improvement program will need to address both internal and external factors, there were no studies found presenting strong evidence of the efficacy of such an intervention.
Conclusion
Studies with multifactorial interventions to improve sleep are difficult to conduct and interpret. The majority of the experimental research reviewed for this paper employed a combination of strategies to improve sleep for hospitalized patients making it a challenge to isolate the effect of individual strategies. Looking across the research we are able to conclude that hospitals can make quality improvements to support better sleep. The constant level of noise and the number of peak noise events in hospitals is responsible for some of the sleep disruptions, it is modifiable through quiet time protocols and use of single patient rooms, and when reduced leads to more sleep for patients. Although nursing care activities are responsible for sleep disruption, efforts at limiting nurse activity have not been demonstrated to improve sleep conditions. Offering patients earplugs and eye masks is an easy and affordable solution that may help, but changing the sound and light environment is more effective. Positive solutions such as calming music in the evening has been shown to be effective, as well as bright light exposure during the day.
While the research results are uneven and hard to consolidate due to the multitude of independent variables and sleep outcome metrics, overall these studies point to the potential for making meaningful improvements in the quality of patient sleep.
Implications
The disruption of sleep in hospitals results from a number of factors intrinsic to the patient, the external environment and the care process. Altogether the intrinsic and extrinsic factors included in these studies only explained about a quarter of the variance in sleep quality [18, 60] leaving the cause of most of the awakenings/arousals from sleep unexplained.
Even with this uncertainty, this literature review demonstrates that we can make progress; conditions in hospitals can be improved such that patients get a better, even if not perfect, night of sleep. It is also clear that any successful solution will be multifactorial and require involvement of many stakeholders from architects, suppliers, nurses, environmental services, laboratory, clinicians and leadership.
Limitations of this review
A major challenge in summarizing this body of literature has been the diversity of independent and dependent variables making it impossible to compare impacts. A narrower focus could have allowed for more in-depth comparison of the results, but we found it important to include the full range of non-pharmacological approaches. At the same time by limiting our focus to studies conducted in hospitals we have excluded a large body of research on sleep that has taken place with healthy subjects in sleep labs. It is important to recognize that patient subgroups may have sleep challenges related to their health conditions or the specific hospital department [65] and therefore not all solutions will have the same impact across patient types or with healthy subjects.
Research needs
To adequately capture the true impact of multifactorial sleep improvement projects, larger sample sizes will be needed. Additionally, other factors should be considered in the mix. Limited work has been done on the impact of somatosensory stimuli on sleep disruption such as medical devices [8], comfort in bed [66], and skin temperature [67]. The most impactful research at this point may be to quantify the financial costs of these interventions and the impact on a widely recognized metric such as patient satisfaction. Healthcare leaders are likely to pay far more attention to improving sleep conditions if they know it is an affordable way to improve the patient experience.
Acknowledgments
The authors would like to thank the research team at the SimTigrate Design Lab especially Lisa Lim, who helped us in early conceptualization of the project.
Funding
This work was supported by Hill-Rom.
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