title: Effect of oral melatonin and wearing earplugs and eye masks on nocturnal sleep in healthy subjects in a simulated intensive care unit environment: which might be a more promising strategy for ICU sleep deprivation?
abstract: BACKGROUND
  Sleep deprivation is common in critically ill patients in the intensive care unit (ICU). Noise and light in the ICU and the reduction in plasma melatonin play the essential roles. The aim of this study was to determine the effect of simulated ICU noise and light on nocturnal sleep quality, and compare the effectiveness of melatonin and earplugs and eye masks on sleep quality in these conditions in healthy subjects.
  
  
  METHODS
  This study was conducted in two parts. In part one, 40 healthy subjects slept under baseline night and simulated ICU noise and light (NL) by a cross-over design. In part two, 40 subjects were randomly assigned to four groups: NL, NL plus placebo (NLP), NL plus use of earplugs and eye masks (NLEE) and NL plus melatonin (NLM). 1 mg of oral melatonin or placebo was administered at 21:00 on four consecutive days in NLM and NLP. Earplugs and eye masks were made available in NLEE. The objective sleep quality was measured by polysomnography. Serum was analyzed for melatonin levels. Subjects rated their perceived sleep quality and anxiety levels.
  
  
  RESULTS
  Subjects had shorter total sleep time (TST) and rapid eye movement (REM) sleep, longer sleep onset latency, more light sleep and awakening, poorer subjective sleep quality, higher anxiety level and lower serum melatonin level in NL night (P <0.05). NLEE had less awakenings and shorter sleep onset latency (P <0.05). NLM had longer TST and REM and shorter sleep onset latency (P <0.05). Compared with NLEE, NLM had fewer awakenings (P = 0.004). Both NLM and NLEE improved perceived sleep quality and anxiety level (P = 0.000), and NLM showed better than NLEE in perceived sleep quality (P = 0.01). Compared to baseline night, the serum melatonin levels were lower in NL night at every time point, and the average maximal serum melatonin concentration in NLM group was significantly greater than other groups (P <0.001).
  
  
  CONCLUSIONS
  Compared with earplugs and eye masks, melatonin improves sleep quality and serum melatonin levels better in healthy subjects exposed to simulated ICU noise and light.
  
  
  BACKGROUND
  Chinese Clinical Trial Registry ChiCTR-IPR-14005458 . Registered 10 November 2014.
authors.affiliation: Department of Critical Care Medicine, Fuxing Hospital, Capital Medical University, 20A Fu Xing Men Wai Da Jie, Xicheng District, Beijing, 100038, P.R. China. vivian198543@163.com.
authors.forename: Hua-Wei
authors.initials: HW
authors.lastname: Huang
authors.affiliation: Department of Pediatric Surgery, Fuzhou Children's Hospital of Fujian Province, Teaching Hospital of Fujian Medical University, Fuzhou, Fujian, 350005, P.R. China. 125699063@qq.com.
authors.forename: Bo-Lu
authors.initials: BL
authors.lastname: Zheng
authors.affiliation: Department of Critical Care Medicine, Fuxing Hospital, Capital Medical University, 20A Fu Xing Men Wai Da Jie, Xicheng District, Beijing, 100038, P.R. China. jiangli_fxyy@sina.com.
authors.forename: Li
authors.initials: L
authors.lastname: Jiang
authors.affiliation: Department of Otorhinolaryngology, Fuzhou Children's Hospital of Fujian Province, Teaching Hospital of Fujian Medical University, Ba Yi Qi Zhong Road, Gulou District, Fuzhou, Fujian, 350005, P.R. China. 80675849@qq.com.
authors.forename: Zong-Tong
authors.initials: ZT
authors.lastname: Lin
authors.affiliation: Department of Neurosurgery, Beijing Tiantan Hospital, Capital Medical University, Tiantan Xili 6, Chongwen District, Beijing, 100050, P.R. China. guobin_0912@sina.com.
authors.forename: Guo-Bin
authors.initials: GB
authors.lastname: Zhang
authors.affiliation: Department of Otorhinolaryngology, Fuzhou Children's Hospital of Fujian Province, Teaching Hospital of Fujian Medical University, Ba Yi Qi Zhong Road, Gulou District, Fuzhou, Fujian, 350005, P.R. China. shenlingfz@126.com.
authors.forename: Ling
authors.initials: L
authors.lastname: Shen
authors.affiliation: Department of Critical Care Medicine, Fuxing Hospital, Capital Medical University, 20A Fu Xing Men Wai Da Jie, Xicheng District, Beijing, 100038, P.R. China. xxm_fxyy@sina.cn.
authors.forename: Xiu-Ming
authors.initials: XM
authors.lastname: Xi
mesh_terms: D000328:Adult; D002492:Central Nervous System Depressants / Q000627:therapeutic use*; D004430:Ear Protective Devices; D004781:Environmental Exposure / Q000009:adverse effects; D005135:Eye Protective Devices; D064368:Healthy Volunteers; D006801:Humans; D007362:Intensive Care Units; D008027:Light / Q000009:adverse effects; D008550:Melatonin / Q000097:blood / Q000627:therapeutic use*; D008875:Middle Aged; D009622:Noise / Q000009:adverse effects; D017286:Polysomnography; D012892:Sleep Deprivation / Q000517:prevention & control*
chemical_list: D002492:Central Nervous System Depressants; D008550:Melatonin