***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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    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 Objective To assess and compare the impact of overnight sedation with midazolam or propofol on anxiety and depression levels , as well as sleep quality , in non-intubated patients in intensive care . Design Open , comparative , prospect i ve , r and omised study . Setting Surgical intensive care unit ( ICU ) in a university hospital . Patients 40 conscious patients expected to stay in the ICU for at least 5 days who were admitted following trauma or elective orthopaedic , thopaedic , thoracic or abdominal surgery . Measurements and results Evaluation of a self- assessment scale ( Hospital Anxiety and Depression Scale , HAD ) on the day following the 1st , 3rd and 5th night of sedation with either midazolam or propofol .  Heart rate , pulse oximetry and blood gases were monitored . Eight patients were excluded from the analysis . The level of anxiety was severe ( HAD>10 ) in 31 % of the patients receiving midazolam and in 26 % ( p=0.1 ) receiving propofol after the first night of sedation , with no significant improvement over the next few days . The levels of depression remained high ( > 10 ) in 54 % of patients receiving midazolam , and in 16 % of the patients receiving propofol ( p=0.15 ) . Sleep quality tended to improve during the study in the two groups . Conclusions These data show that half of the patients in the ICU experienced high levels of anxiety and depression during the first 5 postoperative or post-trauma days in the ICU . The beneficial effects of sedation on sleep quality were comparable for midazolam and propofol , regardless of a lack of improvement in anxiety and depression . However , an improved quality of sleep could help to re-establish a physiological night and day rhythm Objective : To determine whether benzodiazepine and propofol doses are increased at night and whether daytime and nighttime sedative doses are associated with delirium , coma , and delayed liberation from mechanical ventilation . Design : Single-center , prospect i ve cohort study nested within the Awakening and Breathing Controlled r and omized trial . Setting : Saint Thomas Hospital in Nashville , TN , from 2004 to 2006 . Patients : Adult patients receiving mechanical ventilation for > 12 hrs with continuous recording of hourly sedation dosing . Interventions : We measured hourly doses of benzodiazepine and propofol exposure during the daytime ( 7 AM to 11 PM ) and nighttime ( 11 PM to 7 AM ) for 5 days . We quantified nighttime dose increases by subtracting the average hourly daytime dose on the preceding day from subsequent average hourly nighttime dose . We used multivariable logistic regression to determine whether daytime and nighttime dose increases were independently associated with delirium , coma , and delayed liberation from mechanical ventilation . Measurements and Main Results : Among 140 patients , the  median Acute Physiology and Chronic Health Evaluation II score  was 27 ( interquartile range 22–33 ) . Among those receiving the sedatives ,  benzodiazepine and propofol doses were increased at night on 40 % and 41 % of patient-days , respectively . Of 485 patient-days , delirium was present on 160 ( 33 % ) and coma on 206 ( 42 % ) . In adjusted models , greater daytime benzodiazepine dose was independently associated with failed spontaneous breathing trial and extubation , and subsequent delirium ( p < .02 for all ) . Nighttime increase in benzodiazepine dose was associated with failed spontaneous breathing trial ( p < .01 ) and delirium ( p = .05 ) . Daytime propofol dose was marginally associated with subsequent delirium ( p = .06 ) . Conclusions : Nearly half of mechanically ventilated intensive care unit patients received greater doses of sedation at night , a practice associated with failed spontaneous breathing trials , coma , and delirium . Over the first 5 days in our study , patients spent 75 % of their time in coma or delirium , outcomes that may be reduced by efforts to decrease sedative exposure during both daytime and nighttime hours in the intensive care unit Objective To assess survival , morbidity ( physical and psychological ) , quality of life ( QOL ) , and employment status of intensive care survivors up to 12 months after discharge from the intensive care unit ( ICU ) . Design Prospect i ve study . Setting University hospital adult ICU . Patients Between August 1 , 1995 , and July 31 , 1996 , 370 patients were admitted . Of these patients , 29 % died in the ICU . Three months after discharge from the ICU , 227 patients were alive , and 143 agreed to participate .  Cumulative mortality was calculated using the original complete cohort . Measurements and Main Results Demographic data , severity of acute illness ( Acute Physiology and Chronic Health Evaluation [ APACHE ] II ) , admitting specialty , primary diagnosis , and length of stay were recorded . Physical and ICU-related psychological morbidity ( Hospital Anxiety and Depression scale score ) were recorded . Health-related QOL was assessed using the Short-Form 36 . All the question naires were completed in the clinic at 3 months . Assessment of physical morbidity and employment status at 6 and 12 months were conducted by telephone . The cumulative mortality was 39 % at 3 months , 41 % at 6 months , and 43 % at 12 months . Deaths after 3 months occurred in the group who refused follow-up . The median age for the follow-up group was 51 yrs ; the gender split was 68 women and 75 men ; the mean admission APACHE II score was 18.79 ( sd 6.15 ) ; and the median length of ICU stay was 3.8 days . At 3 months , ∼80 % of all patients interviewed were satisfied with their QOL . Older men ( > 65 yrs ) and younger women ( < 65 yrs ) demonstrated significantly better health with respect to some subdomains of the Short-Form 36 compared with their counterparts . The prevalence of psychological distress ( Hospital Anxiety and Depression scale score , ≥8 ) was low : 11.9 % had heightened anxiety , and 9.8 % were depressed . There were high levels of fatigue , poor concentration , and sleep disturbance ; the latter was more marked in women ( p = .022 ) . Improvement in all three symptoms occurred during the next 9 months . Significantly more women reported loss of hair ( p < .0001 ) . Men were slower to return to employment ; 75 % of women had returned by 6 months compared with only 65 % of men at 1 yr . Conclusion Assessment of outcome after ICU stay must include QOL measurements . Three months after discharge , there is a low incidence of ICU-related psychological or psychiatric illness and the majority of patients are satisfied . Differences in the incidence and nature of morbidity exist between the genders STUDY OBJECTIVES The effect of opioid medications on sleep architecture has been demonstrated in patients with comorbid pain or opioid addiction . This study examined whether commonly used opioid medications have an adverse effect on sleep architecture in healthy adults . METHODS Forty-two healthy subjects were examined with  polysomnography  after a bedtime dose of placebo , sustained-release morphine sulfate ( 15 mg ) , or methadone ( 5 mg ) on each of 3 different nights in a double-blind multiple crossover study in a sleep laboratory in the General Clinical Research Center at an academic medical center . RESULTS Both opioid drugs significantly reduced deep sleep and increased stage 2 sleep ( both p < .01 ) ; neither had an effect on sleep efficiency , wake after sleep onset , or total sleep time . CONCLUSIONS Single doses of oral opioid medications can significantly affect sleep architecture in healthy adults , and observed reductions in slow-wave sleep following opioid administration may have important implication s for the pathogenesis of opioid-use related fatigue Objective : The assessment of propofol to produce diurnal sedation in critically ill patients Design : Prospect i ve clinical study Setting : Intensive Care Unit , University Hospital Patients and participants : Thirty consecutive patients admitted to the Intensive Care Unit older than 18 years who were expected to be se date d for more than 50 h Interventions : The patients were r and omised into two groups . All received sedation with a constant background infusion of morphine and a variable infusion rate of propofol , which was altered hourly to maintain the intended sedation score . The first group received constant light sedation ( CLS ) over 50 h aim ing for a Ramsay score of 2–3 . The second group received CLS between 0600 h and 2200 h and additional night sedation ( ANS ) with propofol between 2200 h and 0600 h , aim ing for a sedation score of 4–5 . Measurements and results : Patients were studied for 50 h from 1800 h on the first day of admission . Recordings of heart rate , blood pressure , sedation scores and propofol and morphine infusion rates were made hourly . An APACHE II score was recorded for each patient . Sedation scores were analysed by blind visual assessment and cosinor analysis , which is used in chronobiology to examine the correlation of data with a cosine curve . Patients in the ANS group had significantly better rhythmicity of sedation levels using cosinor analysis ( r = 26 % v 8 % ) p < 0.01 . There was no difference between the CLS and ANS groups with respect to age , sex or APACHE II scores . Nine out of 15 patients in the ANS group achieved diurnal sedation . Three patients in the CLS group showed diurnal rhythmicity of sedation , which can be attributed to natural sleep , and had a median APACHE II score of 12 . Five patients in the CLS group and three in the ANS group showed a deep constant sedation pattern . They had high APACHE II scores ( median 21.5 ) and an obtunded conscious level on admission due to severe sepsis . Conclusion : Propofol can safely provide diurnal sedation in the critically ill when titrated against the Ramsay score . Sedation levels can not be manipulated in some severely ill patients CONTEXT In the intensive care unit ( ICU ) , delirium is a common yet underdiagnosed form of organ dysfunction , and its contribution to patient outcomes is unclear . OBJECTIVE To determine if delirium is an independent predictor of clinical outcomes , including 6-month mortality and length of stay among ICU patients receiving mechanical ventilation . DESIGN , SETTING , AND PARTICIPANTS Prospect i ve cohort study enrolling 275 consecutive mechanically ventilated patients admitted to adult medical and coronary ICUs of a US university-based medical center between February 2000 and May 2001 . Patients were followed up for development of delirium over 2158 ICU days using the Confusion Assessment Method for the ICU and the Richmond Agitation-Sedation Scale . MAIN OUTCOME MEASURES Primary outcomes included 6-month mortality , overall hospital length of stay , and length of stay in the post-ICU period . Secondary outcomes were ventilator-free days and cognitive impairment at hospital discharge . RESULTS Of 275 patients , 51 ( 18.5 % ) had persistent coma and died in the hospital . Among the remaining 224 patients , 183 ( 81.7 % ) developed delirium at 
    Output:
    
We found insufficient evidence to determine whether administration of propofol would improve the quality and quantity of sleep in adults in the ICU .