***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: Previous studies showed that decreased cerebral saturation during cardiac surgery is related to adverse postoperative outcome . Therefore , we investigated the influence of intraoperative events on cerebral tissue saturation in patients undergoing cardiac surgery with cardiopulmonary bypass ( CPB ) .  A total of 52 adult patients who underwent cardiac surgery using pulsatile CPB  were included in this prospect i ve explorative study . Cerebral tissue oxygen saturation ( SctO2 ) was measured in both the left and right cerebral hemisphere . Intraoperative events , involving interventions performed by anesthesiologist , surgeon , and clinical perfusionist , were documented . Simultaneously , in-line hemodynamic parameters ( partial oxygen pressure , partial carbon dioxide pressure , hematocrit , arterial blood pressure , and CPB flow rates ) were recorded . Cerebral tissue saturation was affected by anesthetic induction ( p < .001 ) , placement of the sternal retractor ( p < .001 ) , and initiation ( p < .001 ) as well as termination of CPB ( p < .001 ) . Placement ( p < .001 ) and removal of the aortic cross-clamp ( p = .026 for left hemisphere , p = .048 for right hemisphere ) led to changes in cerebral tissue saturation . In addition , when placing the aortic crossclamp , hematocrit ( p < .001 ) as well as arterial ( p = .007 ) and venous ( p < .001 ) partial oxygen pressures changed . Cerebral tissue oximetry effectively identifies changes related to surgical events or vulnerable periods during cardiac surgery . Future studies are needed to identify methods of mitigating periods of reduced cerebral saturation Background Blood transfusions are common in cardiac surgery , but have been associated with increased morbidity and long-term mortality . Efforts to reduce blood product use during cardiac surgery include fluid restriction to minimize hemodilution , and protocol s to guide transfusion decisions . INVOS is a modality that monitors brain tissue oxygen saturation , and could be useful in guiding decisions to transfuse . However , the role of  INVOS  ( brain tissue oxygen saturation ) as part of an algorithm to direct blood transfusions during cardiac surgery has not been evaluated . This study was conducted to investigate the value of INVOS as part of a protocol for blood transfusions during cardiac surgery . Methods Prospect i ve , r and omized , blinded clinical trial , on 150 ( 75 per group ) elective cardiac surgery patients . The study was approved by the Institution Ethics committee and all patients gave written informed consent . Data were initially analyzed based on “ intention to treat ” , but subsequently were also analyzed “ per protocol ” . Results When protocol was strictly followed ( “ per protocol analysis ” ) , compared to the control group , significantly fewer patients monitored with INVOS received any blood transfusions ( 46 of 70 patients in INVOS group vs. 55 of 67 patients in the control group , p = 0.029 ) . Similarly , patients monitored with INVOS received significantly fewer units of red blood cell transfusions intraoperatively ( 0.20 ± 0.50 vs. 0.52 ± 0.88 , p = 0.008 ) and overall during hospital stay ( 1.31 ± 1.20 vs. 1.82 ± 1.46 , p = 0.024 ) . When data from all patients ( including patient with protocol violation ) were analyzed together ( “ intention to treat analysis ” ) , the observed reduction of blood transfusions in the INVOS group was still significant ( 51 of 75 patients transfused in the INVOS group vs. 63 of 75 patients transfused in the control group , p = 0.021 ) , but the overall number of units transfused per patient did not differ significantly between the groups ( 1.55 ± 1.97 vs. 1.84 ± 1.41 , p = 0.288 ) . Conclusions Our data suggest that INVOS could be a useful tool as part of an algorithm to guide decisions for blood transfusion in cardiac surgery . Additional data from rigorous , well design ed studies are needed to further evaluate the role of INVOS in guiding blood transfusions in cardiac surgery , and circumvent the limitations of this study .Trial registration Clinical Trials.gov : Background We assessed whether a near-infrared spectroscopy (NIRS)-based algorithm for the personalized optimization of cerebral oxygenation during cardiopulmonary bypass combined with a restrictive red cell transfusion threshold would reduce perioperative injury to the brain , heart , and kidneys . Methods In a r and omized controlled trial , participants in three UK centres were r and omized with concealed allocation to a NIRS ( INVOS 5100 ; Medtronic Inc. , Minneapolis , MN , USA)-based ' patient-specific ' algorithm that included a restrictive red cell transfusion threshold ( haematocrit 18 % ) or to a ' generic ' non-NIRS-based algorithm ( st and ard care ) . The NIRS algorithm aim ed to maintain cerebral oxygenation at an absolute value of > 50 % or at > 70 % of baseline values . The primary outcome for the trial was cognitive function measured up to 3 months postsurgery . Results The analysis population comprised eligible r and omized patients who underwent valve or combined valve surgery and coronary artery bypass grafts using cardiopulmonary bypass between December 2009 and January 2014 ( n = 98 patient-specific algorithm ; n = 106 generic algorithm ) . There was no difference between the groups for the three core cognitive domains ( attention , verbal memory , and motor coordination ) or for the non-core domains psychomotor speed and visuo-spatial skills . The NIRS group had higher scores for verbal fluency ; mean difference 3.73 ( 95 % confidence interval 1.50 , 5.96 ) . Red cell transfusions , biomarkers of brain , kidney , and myocardial injury , adverse events , and health-care costs were similar between the groups . Conclusions These results do not support the use of NIRS-based algorithms for the personalized optimization of cerebral oxygenation in adult cardiac surgery . Clinical trial registration http://www.controlled-trials.com , IS RCT N 23557269 OBJECTIVES The aim of this study is the assessment of the regional cerebral oximetry - NIRS ( near infrared spectroscopy ) as an intraoperative monitoring system to protect the patient against the incidents of brain desaturations . We hypothesize that patients monitored with NIRS present a smaller range of postoperative cognitive dysfunctions ( POCD ) in comparison with those without NIRS monitoring during lumbar spine surgery in a prone position . SETTING S This study was performed at the Clinical Department of Neurosurgery and Oncology of the Central Nervous System , Medical University of Lodz , Pol and . PARTICIPANTS The study completed 43 adult patients qualified for the surgical treatment of lumbar spondylosis . Before the procedures they were r and omized into two subgroups : one monitored intraoperatively by means of NIRS cerebral oximetry ( INVOS 5100 ) , which numbered 13 patients – 30.2 % ( 13 NIRS devices were made available to the authors ) and the other without NIRS intraoperative monitoring , totaling 30 people – 69.8 % . The patients who presented a history of psychiatric , neurological and cardiovascular disorders which impair cognitive processes were disqualified from the study . PRIMARY AND SECONDARY OUTCOME MEASURES A comprehensive battery of neuropsychological tests was preoperatively performed on all patients . The subjects were then divided into two groups : with and without NIRS monitoring . Both groups were statistically homogeneous . Computerized anesthesia records were used to obtain intraoperative data : mean arterial pressure , heart rate , pulsoximetry and cerebral regional oxygenation . The depth of anesthesia monitor was not used . Besides , all the patients passed the same battery of neurocognitive tests 7 days and 1 month postoperatively . The Mann-Whitney test was performed to compare POCD and therefore assess the usefulness of NIRS as a monitoring mechanism during anesthesia in the prone position . RESULTS There was a significant ( p < 0.05 ) difference in the presence of cognitive deficiencies between the subgroup monitored with NIRS and the subgroup without NIRS . It included : Digit Span Test overall score and forward repetition score 7 days after operation , N- back Test results after 30 days in version 0 " back " - time , N-back Test version 1 " back " results in the number of correct answers and the number of errors . CONCLUSIONS NIRS cerebral oximetry may be useful in reducing postoperative cognitive complications in patients operated on in the prone positioning . TRIAL REGISTRATION RNN/556/08/KB – approval of the ethics committee at Medical University of Lodz , Pol and The use of cerebral oximetry to guide intraoperative management has been shown to improve patient outcomes in cardiac surgery . This pilot trial assessed the feasibility of performing a similar study of outcome in patients over the age of 70 years undergoing non-cardiac surgery . Patients over the age of 70 years undergoing total knee or hip arthroplasty or bowel resection surgery were r and omly assigned to have  cerebral oximetry values monitored ( intervention group ) or not monitored ( control ) while under general anaesthesia . Indicators of proof of concept were : rate of complications , rate of cerebral desaturation , relationship between cerebral desaturation and complications , and anaesthetist response to cerebral desaturation .  Forty patients were recruited and r and omised to a control group  ( n=20 ) or an intervention group ( n=20 ) . The proportion of the study population who had a complication was 40 % ( 95 % confidence interval [ CI ] 26 % to 55 % ) . Cerebral desaturation ( < 75 % of baseline ) occurred in only two patients ( 5.0 % ( CI 1.4 % to 16 % ) ) , one in each group , and neither of those patients recorded a complication . Changes to anaesthetic management on the basis of cerebral oximetry values occurred in only two patients in the intervention group ( 10 % ( CI 2.8 % to 30 % ) ) . Maintenance of cerebral oximetry values appeared to be closer to baseline in the intervention group than in the control group but this difference was not significant ( P=0.15 ) . Our results indicated that complications occurred frequently in the study population but did not appear to be associated with cerebral desaturation events . These findings do not support a larger intervention study using the current study population OBJECTIVE The aim of this study was to compare the effect of sevoflurane and propofol on cerebral oxygenation , using regional cerebral oxygen saturation ( SrO2 ) measured by near-infrared spectroscopy ( NIRS ) . STUDY DESIGN Prospect i ve , r and omized , controlled study . PATIENTS AND METHODS Fifty-four patients aged between 18 and 65 years who underwent elective minor surgery ( tumorectomy for breast cancer or inguinal hernia repair ) were r and omly assigned to receive sevoflurane or propofol anaesthesia . Exclusion criteria included pre-existing cerebrovascular diseases , anaemia , ASA > III , blood loss ≥200 mL , arterial hypotension , baseline pulse oximetry < 97 % , sign of sensor low quality of SrO2 or bispectral index , and patients with a forehead area < 6.5 cm . SrO2 , bispectral index , haemodynamic data and anaesthetic doses were recorded during surgery . RESULTS A total of 48 patients were included in the final analysis ( 24 in each group ) . There were no significant differences in mean , minimum and maximum SrO2 between sevoflurane and propofol groups . The relative maximum decrease was higher in propofol anaesthesia than sevoflurane anaesthesia ( 9.6±10.7 versus 4.2±7.2 % ; P=0.048 ) . Cerebral desaturation ( 20 % reduction from SrO2 baseline during 15 seconds ) occurred in 4 patients in propofol group exclusively ( P=0.109 ) . SrO2 adjusted for baseline was higher in the sevoflurane group than in the propofol group ( 67.3±1.8 % versus 64.2±1.7 % ; P=0.018 ) . There were no significant differences in haemodynamic parameters between the two groups . CONCLUSIONS Cerebral cortical oxygenation measured by NIRS may be better preserved with sevoflurane than with propofol . These findings suggest that sevoflurane anaesthesia could be a good option in patients with compromised cerebral oxygenation , given the absence of intracranial hypertension . Further studies with larger sample sizes are required to support our results Flaws in the design , conduct , analysis , and reporting of r and omised trials can cause the effect of an intervention to be underestimated or overestimated . The Cochrane Collaboration ’s tool for assessing risk of bias aims to make the process clearer and more 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 ab 
    Output:
    
Conclusions Intraoperative cerebral oximetry appears to be associated with a reduction in POCD , although this result should be interpreted with caution given the significant heterogeneity in the studies examined .