***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
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    ***EXAMPLES*** 
    Input: Introduction Many intensive care patients experience sleep disruption potentially related tonoise , light and treatment interventions . The purpose of this study was tocharacterise , in terms of quantity and quality , the sleep of intensive care patients , taking into account the impact of environmental factors . Methods This observational study was conducted in the adult ICU of a tertiary referralhospital in Australia , enrolling 57 patients .  Polysomnography ( PSG ) was performedover a 24-hour period to assess the quantity ( total sleep time : hh : mm ) and quality ( percentage per stage , duration of sleep episode ) of patients ' sleep while in ICU.Rechtschaffen and Kales criteria were used to categorise sleep . Interrater checkswere performed . Sound pressure and illuminance levels and care events weresimultaneously recorded . Patients reported on their sleep quality in ICU using theRichards Campbell Sleep Question naire and the Sleep in Intensive Care Question naire . Data were summarised using frequencies and proportions or measures of central tendency and dispersion as appropriate and Cohen 's Kappa statistic wasused for interrater reliability of the sleep data analysis . Results Patients ' median total sleep time was 05:00 ( IQR : 02:52 to 07:14 ) . The majority ofsleep was stage 1 and 2 ( medians : 19 and 73 % ) with scant slow wave and REM sleep . The median duration of sleep without waking was 00:03 . Sound levels were high(mean Leq 53.95 dB(A ) during the day and 50.20 dB(A ) at night ) and illuminancelevels were appropriate at night ( median < 2 lux ) but low during the day(median : 74.20 lux ) . There was a median 1.7 care events/h . Patients ' meanself-reported sleep quality was poor . Interrater reliability of sleep staging washighest for slow wave sleep and lowest for stage 1 sleep . Conclusions The quantity and quality of sleep in intensive care patients are poor and may berelated to noise , critical illness itself and treatment events that disturb sleep . The study highlights the challenge of quantifying sleep in the critical care setting and the need for alternative methods of measuring sleep . The results suggest that a sound reduction program is required and other interventions toimprove clinical practice s to promote sleep in intensive care patients .Trial registration Australian New Zeal and clinical trial registry(http://www.anzctr.org.au/ ) : ACTRN12610000688088 IMPORTANCE No highly effective interventions to prevent delirium have been identified . OBJECTIVE To examine whether ramelteon , a melatonin agonist , is effective for the prevention of delirium . DESIGN , SETTING , AND PARTICIPANTS A multicenter , rater-blinded , r and omized placebo-controlled trial was performed in intensive care units and regular acute wards of 4 university hospitals and 1 general hospital . Eligible patients were 65 to 89 years old , newly admitted due to serious medical problems , and able to take medicine orally . Patients were excluded from the study if they had an expected stay or life expectancy of less than 48 hours . INTERVENTIONS Sixty-seven patients were r and omly assigned using the sealed envelope method to receive ramelteon ( 8 mg/d ; 33 patients ) or placebo ( 34 patients ) every night for 7 days . MAIN OUTCOMES AND MEASURES Incidence of delirium , as defined by the Diagnostic and Statistical Manual of Mental Disorders ( Fourth Edition ) . RESULTS Ramelteon was associated with a lower risk of delirium ( 3 % vs 32 % ; P = .003 ) , with a relative risk of 0.09 ( 95 % CI , 0.01 - 0.69 ) . Even after risk factors were controlled for , ramelteon was still associated with a lower incidence of delirium ( P = .01 ; odds ratio , 0.07 [ 95 % CI , 0.008 - 0.54 ] ) . The Kaplan-Meier estimates of time to development of delirium were 6.94 ( 95 % CI , 6.82 - 7.06 ) days for ramelteon and 5.74 ( 5.05 - 6.42 ) days for placebo . Comparison by log-rank test showed that the frequency of delirium was significantly lower in patients taking ramelteon  than in those taking placebo ( χ(2 ) = 9.83 ; P = .002 ) . CONCLUSIONS AND RELEVANCE Ramelteon administered nightly to elderly patients admitted for acute care may provide protection against delirium . This finding supports a possible pathogenic role of melatonin neurotransmission in delirium . TRIAL REGISTRATION University Hospital Medical Information Network Clinical Trials Registry Identifier : UMIN000005591 Objectives : Occurrence of delirium in the ICU is associated with a longer stay in the ICU . To examine whether the use of ramelteon , a melatonin agonist , can prevent delirium and shorten the duration of ICU stay of critically ill patients . Design : A single-center , triple-blinded , r and omized placebo-controlled trial . Setting : ICU of an academic hospital . Patients : Eligible patients were ICU patients who could take medicines orally or through a nasogastric tube during the first 48 hours of admission . Interventions : The intervention group received ramelteon ( 8 mg/d ) , and the control group received placebo ( 1 g/d of lactose powder ) at 20:00 hours every day until discharge from the ICU . Measurements and Main Results : A total of 88 subjects were r and omized to the ramelteon group ( 45 subjects ) or the placebo group ( 43 subjects ) . As the primary endpoint , there was a trend toward decrease in the duration of ICU stay ( 4.56 d ) in the ramelteon group compared with the placebo group ( 5.86 d ) ( p = 0.082 and p = 0.028 before and after adjustments ) . As the secondary endpoints , statistically significant decreases in the occurrence rate ( 24.4 % vs 46.5 % ; p = 0.044 ) and duration ( 0.78 vs 1.40 d ; p = 0.048 ) of delirium were observed in the ramelteon group . The nonintubated patients of the ramelteon group showed statistically significantly fewer awakenings per night and a higher proportion of nights without awakenings . Conclusions : Ramelteon tended to decrease the duration of ICU stay as well as decreased the occurrence rate and duration of delirium statistically significantly BACKGROUND Traumatic brain injury ( TBI ) is a devastating and costly acquired condition that affects individuals of all ages , races , and geographies via a number of mechanisms . The effects of TBI on melatonin receptors remain unknown . PURPOSE The purpose of this study is to explore whether endogenous changes in two melatonin receptor subtypes ( MT1 and MT2 ) occur after experimental TBI . SAMPLE A total of 25 adult male Sprague Dawley rats were used with 6 or 7 rats per group . METHODS Rats were r and omly assigned to receive either  TBI modeled using controlled cortical impact or sham surgery and to be sacrificed at either 6- or 24-h post-operatively . Brains were harvested , dissected , and flash frozen until whole cell lysates were prepared , and the supernatant fluid aliquoted and used for western blotting . Primary antibodies were used to probe for melatonin receptors ( MT1 and MT2 ) , and beta actin , used for a loading control . ImageJ and Image Lab software were used to quantify the data which was analyzed using t-tests to compare means . RESULTS Melatonin receptor levels were reduced in a brain region- and time point- dependent manner . Both MT1 and MT2 were reduced in the frontal cortex at 24h and in the hippocampus at both 6h and 24h . DISCUSSION MT1 and MT2 are less abundant after injury , which may alter response to MEL therapy . Studies characterizing MT1 and MT2 after TBI are needed , including exploration of the time course and regional patterns , replication in diverse sample s , and use of additional variables , especially sleep-related outcomes . CONCLUSION TBI in rats result ed in lower levels of MT1 and MT2 ; replication of these findings is necessary as is evaluation of the consequences of lower receptor levels CONTEXT Delirium is a common problem in the intensive care unit ( ICU ) . Accurate diagnosis is limited by the difficulty of communicating with mechanically ventilated patients and by lack of a vali date d delirium instrument for use in the ICU . OBJECTIVES To vali date a delirium assessment instrument that uses st and ardized nonverbal assessment s for mechanically ventilated patients and to determine the occurrence rate of delirium in such patients . DESIGN AND SETTING Prospect i ve cohort study testing the Confusion Assessment Method for ICU Patients ( CAM-ICU ) in the adult medical and coronary ICUs of a US university-based medical center . PARTICIPANTS A total of 111 consecutive patients who were mechanically ventilated were enrolled from February 1 , 2000 , to July 15 , 2000 , of whom 96 ( 86.5 % ) were evaluable for the development of delirium and 15 ( 13.5 % ) were excluded because they remained comatose throughout the investigation . MAIN OUTCOME MEASURES Occurrence rate of delirium and sensitivity , specificity , and interrater reliability of delirium assessment  s using the CAM-ICU , made daily by 2 critical care study nurses , compared with assessment s by delirium experts using Diagnostic and Statistical Manual of Mental Disorders , Fourth Edition , criteria . RESULTS A total of 471 daily paired evaluations were completed . Compared with the reference st and ard for diagnosing delirium , 2 study nurses using the CAM-ICU had sensitivities of 100 % and 93 % , specificities of 98 % and 100 % , and high interrater reliability ( kappa = 0.96 ; 95 % confidence interval , 0.92 - 0.99 ) . Interrater reliability measures across subgroup comparisons showed kappa values of 0.92 for those aged 65 years or older , 0.99 for those with suspected dementia , or 0.94 for those with Acute Physiology and Chronic Health Evaluation II scores at or above the median value of 23 ( all P<.001 ) . Comparing sensitivity and specificity between patient subgroups according to age , suspected dementia , or severity of illness showed no significant differences . The mean ( SD ) CAM-ICU administration time was 2 ( 1 ) minutes . Reference st and ard diagnoses of delirium , stupor , and coma occurred in 25.2 % , 21.3 % , and 28.5 % of all observations , respectively . Delirium occurred in 80 ( 83.3 % ) patients during their ICU stay for a mean ( SD ) of 2.4 ( 1.6 ) days . Delirium was even present in 39.5 % of alert or easily aroused patient observations by the reference st and ard and persisted in 10.4 % of patients at hospital discharge . CONCLUSIONS Delirium , a complication not currently monitored in the ICU setting , is extremely common in mechanically ventilated patients . The CAM-ICU appears to be rapid , valid , and reliable for diagnosing delirium in the ICU setting and may be a useful instrument for both clinical and research purpose Background : Postoperative neurological injuries , including cognitive dysfunction , sleep disorder , delirium , and anxiety , are the important consequences of  coronary artery bypass graft surgery ( CABG ) . Evidence has shown that postoperative sleep disturbance is partly due to disturbed melatonin secretion in the perioperative period . The aim of this study was to evaluate the effect of melatonin on postoperative sleep disorder in patients undergoing CABG . Method : One hundred forty-five elective CABG patients participated in a r and omized double-blind study during the preoperative period . The patients were r and omized to receive either 3 mg of melatonin or 10 mg of Oxazepam one hour before sleep time . Each group received the medication from 3 days before surgery until the time of discharge . Sleep quality was evaluated using the Groningen Sleep Quality Score ( GSQS ) , and the incidence of delirium was evaluated by nursing records . Sleep quality and anxiety scores were compared before and after surgery through the Wilcoxon signed-rank test . The analysis of covariance ( ANCOVA ) and independent t-test were used to compare the sleep and anxiety scores between the groups . P values ≤ 0.05 were considered statistically significant . Results : Totally , 137 patients at a mean age of 60 years completed the study ( 76 % male ) . The analysis of the data showed that sleep was significantly disturbed after surgery in both groups . The patients in the Oxazepam group demonstrated significantly higher disturbance in their mean postoperative GSQS score than did their counterparts in the melatonin group ( p value < 0.001 ) . A smaller proportion of the participants experienced delirium in the melatonin group ( 0.06 % ) than in the Oxazepam group ( 0.12 % ) ; however , this difference was not statistically significant . Conclusion : The result of the present study revealed that melatonin  improved sleep in post-cardiac surgery patients more than what was observed with Oxazepam . Therefore , melatonin may be considered an effective alternative for Benzodiazepines in the management of postoperative sleep disorder BACKGROUND AND AIM Patients in the intensive care unit often suffer from lack of sleep at night . We hypothesised that nocturnal melatonin may increase observed nocturnal sleep in tracheost 
    Output:
    
Exogenous administration of melatonin and melatonin receptor agonists could improve the sleep of subjects in the intensive care units , which may play an important role in decreasing the prevalence of delirium and shortening duration of ICU stay