***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: OBJECTIVE To determine whether limiting intraoperative sedation depth during spinal anesthesia for hip fracture repair in elderly patients can decrease the prevalence of postoperative delirium . PATIENTS AND METHODS We performed a double-blind , r and omized controlled trial at an academic medical center of elderly patients ( > or=65 years ) without preoperative delirium or severe dementia who underwent hip fracture repair under spinal anesthesia with propofol sedation . Sedation depth was titrated using processed electroencephalography with the bispectral index ( BIS ) , and patients were r and omized to receive either deep ( BIS , approximately 50 ) or light ( BIS , > or=80 ) sedation . Postoperative delirium was assessed as defined by Diagnostic and Statistical Manual of Mental Disorders ( Third Edition Revised ) criteria using the Confusion Assessment Method beginning at any time from the second day after surgery . RESULTS From April 2 , 2005 , through October 30 , 2008 , a total of 114 patients were r and omized . The prevalence of postoperative delirium was significantly lower in the light sedation group ( 11/57 [ 19 % ] vs 23/57 [ 40 % ] in the deep sedation group ; P=.02 ) , indicating that 1 incident of delirium will be prevented for every 4.7 patients treated with light sedation . The mean + /- SD number of days of delirium during hospitalization was lower in the light sedation group than in the deep sedation group ( 0.5+/-1.5 days vs 1.4+/-4.0 days ; P=.01 ) . CONCLUSION The use of light propofol sedation decreased the prevalence of postoperative delirium by 50 % compared with deep sedation . Limiting depth of sedation during spinal anesthesia is a simple , safe , and cost-effective intervention for preventing postoperative delirium in elderly patients that could be widely and readily adopted Aim of the study - General anesthetics , arterial hypotension and hypoxia developing during anesthesia may result in impaired memory and a decline in other abilities ( such as attention , concentration , linguistic and writing abilities ) . Our aim was to detect changes in cognitive functions due to surgery and anesthesia with controlled arterial hypotension . Material s and methods - We studied  combined and intravenous anesthesia detecting pre- and postoperative cognitive functions , intraoperative haemodynamic parameters , demographic data , other data of case history and surgical data . The  Montreal Cognitive Assessment test  was applied in the r and omized , prospect i ve study . The preoperative data served as basis for comparison . The second test was performed following surgery when patients were fully awake . Both groups included 30 patients . Results and conclusion - After both narcosis methods ( postoperative second hour ) cognitive functions were significantly deteriorated ( p<0.05 ) . Median MoCA before sevoflurane anesthesia  was 24 points ( interquartile range : 22 - 25 ) , postoperative value was 20 ( 19 - 21 ) ( p<0.05 ) . Median MoCA before propofol anesthesia was 24 points ( 23 - 26 ) , postoperative value was 20 ( 18 - 22 ) ( p<0.01 ) . Intraoperative arterial blood pressure , pulse rate and oxygen saturation values did not correlate with worsening of cognitive function ( Pearson correlation coefficient values between -0.19 and 0.42 ) . Execution is influenced by age ( negative correlation ) and education ( positive correlation ) Clinical observation , as well as r and omized controlled trials , indicated an increasing rate of postoperative cognitive dysfunction ( POCD ) with increasing depth of general anesthesia . However , the findings are subject to bias due to varying degree of analgesia . In this trial , we compared the rate of POCD between patients receiving light versus high anesthesia  while holding analgesia comparable using nerve block Purpose This study was design ed to investigate the effect of bispectral index ( BIS ) monitoring on the recovery profiles , level of postoperative cognitive dysfunction , and anesthetic drug requirements of elderly patients undergoing elective orthopedic surgery with general anesthesia . Methods Sixty-eight patients over the age of 60 were r and omized into one of two groups . In the st and ard practice ( SP ) group , the anesthesiologists were blinded to the BIS value , and isoflurane was titrated according to st and ard clinical practice . In the BIS group , isoflurane was titrated to maintain a BIS value between 50–60 . Results The total isoflurane usage was 30 % lower in the BIS group compared to the SP group ( 5.6 ± 3 vs 7.7 ± 3 mL , P < 0.05 ) . The time to orientation was faster in the BIS group compared to the SP group ( 9.5 ± 3vs 13.1 ± 4 min , P < 0.001 ) . There were no differences in the postoperative psychometric tests between the two groups . Conclusions There was no difference in the level of postoperative cognitive dysfunction between the two groups . However , titration of isoflurane using the BIS index decreased utilization of isoflurane and contributed to faster emergence of elderly patients undergoing elective knee or hip replacement surgery . RésuméObjectifRechercher l’effet du monitorage par l’index  bispectral ( BIS ) sur les profils de récupération , le niveau de déficit cognitif postopératoire et les besoins d’anesthésiques chez des patients âgés qui subissent une intervention orthopédique non urgente avec anesthésie générale . MéthodeSoixante-huit patients de plus de 60 ans ont été répartis au hasard en deux groupes . Pour ceux du groupe de pratique courante ( PC ) , la valeur du BIS n’était pas connue des anesthésiologistes et l’isoflurane a été titré selon les normes de la pratique clinique . Pour les patients du groupe BIS , l’isoflurane a été titré de façon à maintenir un BIS entre 50 et 60.RésultatsL’utilisation totale d’isoflurane a été plus basse de 30 % dans le groupe BIS , comparé au groupe PC ( 5,6 ± 3 vs 7,7 ± 3 mL , P < 0,05 ) . Le retour à la conscience a été plus rapide dans le groupe BIS , comparé au groupe PC ( 9,5 ± 3 vs 13,1 ±4 min , P < 0,001 ) . Les tests psychométriques postopératoires n’ont présenté aucune différence intergroupe . Conclusion Le niveau de déficit cognitif postopératoire n’était pas différent d’un groupe à l’autre . Cependant , le titrage de l’isoflurane à l’aide de l’index BIS a permis de réduire l’utilisation d’isoflurane et a favorisé une récupération plus rapide chez des patients âgés qui subissent la mise en place d’une prothèse totale de hanche Background The study determined the one year incidence of post operative cognitive decline ( POCD ) and evaluated the effectiveness of an intra-operative anaesthetic intervention in reducing  post-operative cognitive impairment in older adults ( over 60 years of age ) undergoing elective orthopaedic or abdominal surgery . Methods and Trial Design The design was a prospect i ve cohort study with a nested r and omised , controlled intervention trial , using intra-operative BiSpectral index and cerebral oxygen saturation monitoring to enable optimisation of anaesthesia depth and cerebral oxygen saturation in older adults undergoing surgery . Results In the 52 week prospect i ve cohort study ( 192 surgical patients and 138 controls ) , mild ( χ2 = 17.9 p<0.0001 ) , moderate ( χ2 = 7.8 p = 0.005 ) and severe ( χ2 = 5.1 p = 0.02 ) POCD were all significantly higher after 52 weeks in the surgical patients than among the age matched controls . In the nested RCT , 81 patients were r and omized , 73 contributing to the data analysis ( 34 intervention , 39 control ) . In the intervention group mild POCD was significantly reduced at 1 , 12 and 52 weeks ( Fisher ’s Exact Test p = 0.018 , χ2 = 5.1 p = 0.02 and χ2 = 5.9 p = 0.015 ) , and moderate POCD was reduced at 1 and 52 weeks ( χ2 = 4.4 p = 0·037 and χ2 = 5.4 p = 0.02 ) . In addition there was significant improvement in reaction time at all time-points ( Vigilance Reaction Time MWU Z = −2.1 p = 0.03 , MWU Z = −2.7 p = 0.004 , MWU Z = −3.0 p = 0.005 ) , in MMSE at one and 52 weeks ( MWU Z = −2.9 p = 0.003 , MWU Z = −3.3 p = 0.001 ) , and in executive function at 12 and 52 weeks ( Trail Making MWU Z = −2.4 p = .0.018 , MWU Z = −2.4 p = 0.019 ) . Conclusion POCD is common and persistent in older adults following surgery . The results of the nested RCT indicate the potential benefits of intra-operative monitoring of anaesthetic depth and cerebral oxygenation as a pragmatic intervention to reduce post-operative cognitive impairment . Trial Registration Controlled-Trials.com IS RCT We r and omized 74 patients to either a lower Bispectral Index ( BIS ) regimen ( median BIS , 38.9 ) or a higher BIS regimen ( mean BIS , 50.7 ) during the surgical procedure . Preoperatively and 4–6 wk after surgery , the patients ’ cognitive status was assessed with a cognitive test battery consisting of processing speed index , working memory index , and verbal memory index . Processing speed index was 113.7 ± 1.5 ( mean ± se ) in the lower BIS group versus 107.9 ± 1.4 in the higher BIS group ( P = 0.006 ) . No difference was observed in the other two test battery components . Somewhat deeper levels of anesthesia were therefore associated with better cognitive function 4–6 wk postoperatively , particularly with respect to the ability to process information BACKGROUND  Postoperative delirium in elderly patients is a frequent complication and associated with poor outcome . The aim of this parallel group study was to determine whether monitoring depth of anaesthesia influences the incidence of postoperative delirium . METHODS Patients who were planned for surgery in general anaesthesia expected to last at least 60 min and who were older than 60 yr were included between March 2009 and May 2010 . A total of 1277 patients of a consecutive sample were r and omized ( n=638 open , n=639 blinded ) and the data of 1155 patients were analysed ( n=575 open , n=580 blinded ) . In one group , the anaesthesiologists were allowed to use the bispectral index ( BIS ) data to guide anaesthesia , while in the other group , BIS monitoring was blinded .  Cognitive function was evaluated at baseline , 1 week , and 3 months after operation . RESULTS Delirium incidence was lower in patients guided with BIS . Postoperative delirium was detected in 95 patients ( 16.7 % ) in the intervention group compared with 124 patients ( 21.4 % ) in the control group ( P=0.036 ) . In a multivariate analysis , the percentage of episodes of deep anaesthesia ( BIS values < 20 ) were independently predictive for postoperative delirium ( P=0.006 ; odds ratio 1.027 ) . BIS monitoring did not alter the incidence of postoperative cognitive dysfunction ( 7th day P=0.062 ; 90th day P=0.372 ) . CONCLUSIONS Intraoperative neuromonitoring is associated with a lower incidence of delirium , possibly by reducing extreme low BIS values . Therefore , in high-risk surgical patients , this may give the anaesthesiologist a possibility to influence one precipitating factor in the complex genesis of delirium . Clinical trial registration IS RCT N Register : 36437985 . http://www.controlled-trials.com/IS RCT Objective To investigate whether the depth of total intravenous anesthesia affects postoperative cognitive dysfunction . Methods Ninety-six patients with facial spasm who were scheduled to receive microvascular decompression were r and omly divided into 2 groups : deeper anesthesia ( n=50 ) and lighter anesthesia ( n=46 ) . Exclusion criteria included : a history of neurologic or mental disease , serum creatinine in excess of 177 & mgr;mol/L , active liver disease , cardiac dysfunction , pulmonary dysfunction , endocrine disease , metabolic disease , a history of surgery , fewer than 6 years of school , inability to complete neuropsychologic testing , vision dysfunction , and auditory dysfunction .  Propofol and sufentanil were used for anesthesia induction and propofol and remifentanil were used for the maintenance of anesthesia . A 
    Output:
    
Our findings suggest a protective effect of BIS compared to not using BIS regarding the incidence of POD at 1 day and POCD at 12 weeks .