***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: BACKGROUND Perioperative anemia leads to increased morbidity and mortality and potentially inhibits rehabilitation after hip fracture surgery . As such , the optimum transfusion threshold after hip fracture surgery is unknown . PATIENTS AND METHODS A total of 120 elderly , cognitively intact hip fracture patients admitted from their own home were r and omly assigned to receive transfusion at a hemoglobin threshold of 10.0 g per dL ( liberal ) versus 8.0 g per dL ( restrictive ) in the entire perioperative period . Patients were treated according to a well-defined multimodal rehabilitation program . Primary outcome was postoperative functional mobility measured with the cumulated ambulation score ( CAS ) . RESULTS Patients in the liberal group received transfusions more frequently than those in the restrictive group ( 44 patients vs. 22 patients ; p < 0.01 ) and received more transfusions during hospitalization ( median , 2 units [ interquartile range , 1 - 2 ] vs. 1 [ 1 - 2 ] ; p < 0.0001 ) . There were no significant differences in postoperative rehabilitation scores ( CAS : median , 9 [ 9 - 15 ] vs. 9 [ 9 - 13.5 ] ; p = 0.46 ) or in length of stay ( median , 18 days vs. 16 days , respectively ; p = 0.46 ) . There were fewer patients in the liberal transfusion group with cardiovascular complications ( 2 % vs. 10 % ; p = 0.05 ) and a lower mortality ( 0 % vs. 8 % ; p = 0.02 ) . CONCLUSION Although a liberal transfusion trigger did not result in increased ambulation scores , restrictive transfusion thresholds should be treated with caution in elderly high-risk hip fracture patients , until their safety has been proved in larger r and omized studies BACKGROUND AND OBJECTIVES Red cell transfusion is commonly used in orthopaedic surgery . Evidence suggests that a restrictive transfusion strategy may be safe for most patients . However , concern has been raised over the risks of anaemia in those with ischaemic cardiac disease .  Perioperative silent myocardial ischaemia ( SMI ) has a relatively high incidence in the elderly population undergoing elective surgery . This study used Holter monitoring to compare the effect of a restrictive and a liberal red cell transfusion strategy on the incidence of SMI in patients without signs or symptoms of ischaemic heart disease who were undergoing lower limb arthroplasty . MATERIAL S AND METHODS We performed a multicentre , controlled trial in which 260 patients undergoing elective hip and knee replacement surgery were enrolled and r and omized to transfusion triggers that were either restrictive ( 8 g/dl ) or liberal ( 10 g/dl ) . Participants were monitored with  continuous ambulatory electrocardiogram ( ECG ) ( Holter monitoring ) , preoperatively for 12 h and postoperatively for 72 h. The tapes were analysed for new ischaemia by technicians blinded to treatment . The total ischaemia time in minutes was divided by the recording time in hours and an ischaemic load in min/h was calculated . Haemoglobin levels were measured preoperatively , postoperatively in the recovery room , and on days one , three and five after surgery . RESULTS The mean postoperative haemoglobin concentration was 9.87 g/dl in the restrictive group and 11.09 g/dl in the liberal group . In the restrictive group , 34 % were transfused a total of 89 red cell units , and in the liberal group 43 % were given a total of 119 red cell units . A postoperative episode of silent ischaemia was experienced by 21/109 ( 19 % ) patients in the restrictive group and by 26/109 ( 24 % ) patients in the liberal group [ mean difference -4.6 % ; 95 % confidence interval ( CI ) : -15.5 % to 6 % , P = 0.41 ) . There was no significant difference ( P = 0.53 ) between the overall ischaemic load in the restrictive group ( median 0 min/h , range 0 - 4.18 ) and the liberal group ( median 0 min/h , range 0 - 19.48 ) . In those patients who did experience postoperative SMI , the mean ischaemic load was 0.48 min/h in the restrictive group and 1.51 min/h in the liberal group ( ratio 0.32 , 95 % CI : 0.14 - 0.76 , P = 0.011 ) . The median postoperative length of hospital stay in the restrictive group was 7.3 days [ range 5 - 11 ; interquartile range ( IQR ) 6 - 8 ] compared with 7.5 days ( range 5 - 13 ; IQR 7 - 8 ) in the liberal group . The numbers were not large enough to conclude equivalence . CONCLUSIONS In patients without preoperative evidence of myocardial ischaemia undergoing elective hip and knee replacement surgery , a restrictive transfusion strategy seems unlikely to be associated with an increased incidence of SMI . A proportion of these patients experience moderate SMI , regardless of the transfusion trigger . Use of a restrictive transfusion strategy did not increase length of hospital stay , and use of this strategy would lead to a significant reduction in red cell transfusion in orthopaedic surgery . Our data did not indicate any potential for harm in employing such a strategy in patients with no prior evidence of cardiac ischaemia who were undergoing elective orthopaedic surgery OBJECTIVE In elective orthopaedic hip- and knee replacement surgery patients , we studied the effect of implementation of a uniform transfusion policy on RBC usage . STUDY DESIGN AND METHODS A r and omized , controlled study . A new uniform , restrictive transfusion policy was compared with st and ard care , which varied among the three participating hospitals . Only prestorage leucocyte-depleted RBC(s ) were used . Primary end-point was RBC usage , related to length of hospital stay . Secondary end-points were Hb levels , mobilization delay and postoperative complications . RESULTS Six hundred and three patients were evaluated .  Adherence to the protocol was over 95 % . Overall mean RBC usage was 0.78 U/patient in the new policy group and 0.86 U/patient in the st and ard care policy group ( mean difference 0.08;95 % CI [ -0.3 ; 0.2 ] ; P = 0.53 ) . In two hospitals , the new transfusion policy result ed in a RBC reduction of 30 % ( 0.58U RBC/patient ) ( P = 0.17 ) and 41 % ( 0.29 U RBC/patient ) ( P = 0.05 ) respectively . In the third hospital , however , RBC usage increased by 39 % ( 0.31 U RBC/patient ) ( P = 0.02 ) with the new policy , due to a more restrictive st and ard care policy in that hospital . Length of hospital stay was not influenced by either policy . CONCLUSIONS Implementation of a uniform transfusion protocol for elective lower joint arthroplasty patients is feasible , but does not always lead to a RBC reduction . Length of hospital stay was not affected Background : Several studies have indicated that a restrictive erythrocyte transfusion strategy is as safe as a liberal one in critically ill patients , but there is no clear evidence to support the superiority of any perioperative transfusion strategy in patients with cancer . Methods : In a r and omized , controlled , parallel-group , double-blind ( patients and outcome assessors ) superiority trial in the intensive care unit of a tertiary oncology hospital , the authors evaluated whether a restrictive strategy of erythrocyte transfusion ( transfusion when hemoglobin concentration < 7 g/dl ) was superior to a liberal one ( transfusion when hemoglobin concentration < 9 g/dl ) for reducing mortality and severe clinical complications among patients having major cancer surgery . All adult patients with cancer having major abdominal surgery who required postoperative intensive care were included and r and omly allocated to treatment with the liberal or the restrictive erythrocyte transfusion strategy . The primary outcome was a composite endpoint of mortality and morbidity . Results : A total of 198 patients were included as follows : 101 in the restrictive group and 97 in the liberal group . The primary composite endpoint occurred in 19.6 % ( 95 % CI , 12.9 to 28.6 % ) of patients in the liberal- strategy group and in 35.6 % ( 27.0 to 45.4 % ) of patients in the restrictive- strategy group ( P = 0.012 ) . Compared with the restrictive strategy , the liberal transfusion strategy was associated with an absolute risk reduction for the composite outcome of 16 % ( 3.8 to 28.2 % ) and a number needed to treat of 6.2 ( 3.5 to 26.5 ) . Conclusion : A liberal erythrocyte transfusion strategy with a hemoglobin trigger of 9 g/dl was associated with fewer major postoperative complications in patients having major cancer surgery compared with a restrictive strategy CONTEXT Perioperative red blood cell transfusion is commonly used to address anemia , an independent risk factor for morbidity and mortality after cardiac operations ; however , evidence regarding optimal blood transfusion practice in patients undergoing cardiac surgery is lacking . OBJECTIVE To define whether a restrictive perioperative red blood cell transfusion strategy is as safe as a liberal strategy in patients undergoing elective cardiac surgery . DESIGN , SETTING , AND PATIENTS The Transfusion Requirements After Cardiac Surgery ( TRACS ) study , a prospect i ve , r and omized , controlled clinical noninferiority trial conducted between February 2009 and February 2010 in an intensive care unit at a university hospital cardiac surgery referral center in Brazil . Consecutive adult patients ( n = 502 ) who underwent cardiac surgery with cardiopulmonary bypass were eligible ; analysis was by intention-to-treat . INTERVENTION Patients were r and omly assigned to a liberal strategy of blood transfusion ( to maintain a hematocrit ≥30 % ) or to a restrictive strategy ( hematocrit ≥24 % ) . MAIN OUTCOME MEASURE Composite end point of 30-day all-cause mortality and severe morbidity ( cardiogenic shock , acute respiratory distress syndrome , or acute renal injury requiring dialysis or hemofiltration ) occurring during the hospital stay . The noninferiority margin was predefined at -8 % ( ie , 8 % minimal clinical ly important increase in occurrence of the composite end point ) . RESULTS Hemoglobin concentrations were maintained at a mean of 10.5 g/dL ( 95 % confidence interval [ CI ] , 10.4 - 10.6 ) in the liberal- strategy group and 9.1 g/dL ( 95 % CI , 9.0 - 9.2 ) in the restrictive- strategy group ( P < .001 ) . A total of 198 of 253 patients ( 78 % ) in the liberal- strategy group and 118 of 249 ( 47 % ) in the restrictive- strategy group received a blood transfusion ( P < .001 ) . Occurrence of the primary end point was similar between groups ( 10 % liberal vs 11 % restrictive ; between-group difference , 1 % [ 95 % CI , -6 % to 4 % ] ; P = .85 ) . Independent of transfusion strategy , the number of transfused red blood cell units was an independent risk factor for clinical complications or death at 30 days ( hazard ratio for each additional unit transfused , 1.2 [ 95 % CI , 1.1 - 1.4 ] ; P = .002 ) . CONCLUSION Among patients undergoing cardiac surgery , the use of a restrictive perioperative transfusion strategy compared with a more liberal strategy result ed in noninferior rates of the combined outcome of 30-day all-cause mortality and severe morbidity . TRIAL REGISTRATION clinical trials.gov Identifier : NCT01021631 BACKGROUND AND OBJECTIVES Cardiac surgery is currently considered one of the heaviest users of red blood cells . An explanation may be found , in part , in considering the effect of the heavy clear fluid load associated with cardiopulmonary bypass . This may result in the artificial depression of haemoglobin concentration , overestimating the requirement for red cell transfusion if this is the sole parameter considered . To address this issue , we examined the impact of a red cell volume-based transfusion guideline on transfusion requirement . MATERIAL S AND METHODS This was a single-centre , r and omized controlled trial . The cohort of 86 patients was allocated to receive red cells as per the red cell volume guideline ( group RCV ) or st and ard haemoglobin concentration-based departmental policy ( group C ) . Outcome measures were red cell transfusion and clinical outcome . RESULTS All preoperative data were comparable between the two groups . A significantly fewer percentage of patients in group RCV were transfused red cells ( RCV = 32.6 % vs. C = 53.5 % , P = 0.05 ) . No significant difference was found between any of the outcome measures with the exception of median hospital stay ( RCV = 5.9 days vs. C = 6.8 days , P = 0.02 ) . CONCLUSION In elective cardiac surgery patients , considering haemoglobin concentration alone may overestimate the requirement for red cell transfusion . More research is required to determine the impact of restrictive transfusion policies on clinical outcome following cardiac surgery OBJECTIVES To determine whether a higher blood transfusion threshold would prevent new or worsening delirium symptoms in the 
    Output:
    
No difference was found for infections , although a protective effect may exist .
Risk estimates varied with successful/unsuccessful transfusion protocol implementation .
Restrictive transfusion strategies should be applied with caution in high-risk patients undergoing major surgery