***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: Pediatric patients who undergo posterior spinal fusion surgery to correct scoliosis often require multiple blood transfusions . Tranexamic acid is a synthetic antifibrinolytic drug that reduces transfusion requirements in cardiac surgery and total knee arthroplasty . We evaluated the efficacy of prophylactic tranexamic acid to reduce perioperative blood transfusion requirements in a prospect i ve , double-blinded , placebo control study . Forty patients , 9–18 yr of age , were r and omized to either tranexamic acid ( initial dose of 10 mg/kg and infusion of 1 mg · kg−1 · h−1 ) or placebo ( isotonic saline ) . Perioperative management was st and ardized . A uniform transfusion threshold for noncell saved red blood cells was 7.0 g/dL. The total amount of blood transfused in the perioperative period was significantly reduced in the Tranexamic group ( P = 0.045 ) . No thrombotic complications were detected in either group . The administration of prophylactic tranexamic acid in patients with scoliosis undergoing posterior spinal fusion surgery has the potential to reduce perioperative blood transfusion requirements Background : Excessive bleeding often occurs during pediatric scoliosis surgery and is attributed to numerous factors , including accelerated fibrinolysis . The authors hypothesized that administration of tranexamic acid would reduce bleeding and transfusion requirements during scoliosis surgery . Methods : Forty-four patients scheduled to undergo elective spinal fusion were r and omly assigned to receive either 100 mg/kg tranexamic acid before incision followed by an infusion of 10 mg · kg−1 · h−1 during surgery ( tranexamic acid group ) or 0.9 % saline ( placebo group ) . General anesthesia was administered according to a st and ard protocol . Blood loss , transfusion requirements , coagulation parameters , and complications were assessed . Results : In the tranexamic acid group , blood loss was reduced by 41 % compared with placebo ( 1,230 ± 535 vs. 2,085 ± 1,188 ml ; P < 0.01 ) . The amount of blood transfused did not differ between groups ( 615 ± 460 vs. 940 ± 718 ml ; P = 0.08 ) . Administration of tranexamic acid was a multivariate predictor of blood loss , as was American Society of Anesthesiologists physical status and preoperative platelet count . No apparent adverse drug effects occurred in any patient . Conclusion : Intraoperative administration of tranexamic acid significantly reduces blood loss during spinal surgery in children with scoliosis BACKGROUND Aprotinin and epsilon aminocaproic acid are antifibrinolytic agents used to reduce postoperative blood loss after cardiopulmonary bypass . We compared low dose aprotinin with epsilon aminocaproic acid and a combination of the two agents to reduce postoperative blood loss in infants with congenital cyanotic heart disease undergoing corrective surgical procedures . METHODS This prospect i ve study was conducted r and omly on 300 children . Group I ( n = 80 ) acted as the control and did not receive either of the study drugs . Group II ( n = 100 ) received low dose aprotinin , group III ( n = 60 ) received epsilon aminocaproic acid , and group IV ( n = 60 ) received a combination of the two antifibrinolytic agents . RESULTS The control group had the longest time for sternal closure , maximum blood loss at 24 hours , and greatest requirements for packed red blood cells and platelets . Fibrinogen levels were significantly lower , and levels of fibrin breakdown products were significantly higher compared with the groups given either or both of the antifibrinolytics . CONCLUSIONS Epsilon aminocaproic acid is as efficacious as low dose aprotinin in reducing postoperative blood loss and packed red blood cell and platelet requirements in children with congenital cyanotic heart disease . The combination of the two was slightly more effective UNLABELLED In this prospect i ve cohort study of 548 children undergoing open-heart surgery  , we evaluated demographic and perioperative factors to identify variables associated with perioperative blood loss and blood product transfusions . Using multivariate analysis , younger patient age was found to be the variable most significantly associated with bleeding and transfusions . Higher preoperative hematocrit , complex surgery , lower platelet count during cardiopulmonary bypass ( CPB ) , and longer duration of deep hypothermic circulatory arrest were also significantly associated with bleeding and transfusion . Excessive postoperative chest tube ( CT ) drainage was associated with intraoperative bleeding . Independently associated variables accounted for 76 % of the variability in CT output measured after 2 h in intensive care . Patients were subdivided into children aged < or = 1 yr ( infants ) and children > 1 yr ; infants bled more intraoperatively ( P<0.005 ) ; had greater cumulative CT output at 2 , 6 , 12 , and 24 h ( P<0.0001 ) ; and received more blood products ( P<0.0001 ) . Factors associated with bleeding and transfusions varied with patient age . Lower body core temperature during CPB was highly associated with blood loss and transfusions in infants , whereas resternotomy , preoperative congestive heart failure , and prolonged duration of CPB were significant factors associated with bleeding and transfusions in children > 1 yr old . IMPLICATION S Knowledge of the factors associated with blood loss and blood product transfusions can help to identify children at risk of excessive bleeding after open-heart surgery Excessive hemorrhage secondary to cardiopulmonary bypass may be encountered after pediatric cardiac operations . Platelet dysfunction appears to be especially responsible for this problem . The proteinase inhibitor aprotinin is suggested to possess platelet preservation properties and reduce blood loss in this situation . The effects of aprotinin ( 25,000 U/kg after induction of anesthesia , 25,000 U/kg added to the prime , 25,000 U/kg every hour of cardiopulmonary bypass ) on platelet function were r and omly studied in 12 children with a weight of less than 10 kg ( group 2 ) and 12 children weighing more than 10 kg ( group 4 ) , who were compared with two groups of children without aprotinin ( group 1 , < 10 kg ; group 3 , > 10 kg ) . Twelve children undergoing major vessel operations without cardiopulmonary bypass and aprotinin  served as a control .  Platelet function was assessed using aggregometry ( turbidometric technique with adenosine diphosphate , 2.0 mumol/L ; collagen , 4 micrograms/mL ; epinephrine , 25 mumol/L ; NaCl [ control ] ) . Platelet function was not altered in the control patients within the entire investigation period . Maximum aggregation in the small children was already lower at baseline in comparison with that of the children > 10 kg . Cardiopulmonary bypass was followed by a significant reduction in platelet aggregation in all groups . Treatment with aprotinin did not improve platelet function ( maximum aggregation and maximum gradient of aggregation ) in any group . On the first postoperative day , maximum aggregation in the small children exceeded baseline values , whereas in both groups of children > 10 kg baseline values had almost been established . Postoperative blood loss was not reduced by treatment with aprotinin . ( ABSTRACT TRUNCATED AT 250 WORDS We performed a prospect i ve , r and omized , placebo-controlled , double-blind trial to assess the efficacy of aprotinin in 61 children ( median age 3.7 yr ) undergoing reoperative open heart surgery ( OHS ) . Three demographically similar groups were studied : large-dose aprotinin ( ALD ) , small-dose aprotinin ( ASD ) , and placebo ( P ) . Over the first 24 postoperative hours fewer patients in the aprotinin groups received packed red cells ( ALD , 53 % ; ASD , 89 % ; and P , 95 % ; P = 0.001 ) , platelets ( ALD , 32 % ; ASD , 50 % ; and P , 65 % ; P = 0.04 ) , and fresh frozen plasma ( ALD , 16 % ; ASD , 17 % ; and P , 60 % ; P = 0.003 ) than placebo patients . Most importantly , aprotinin patients had fewer exposures to banked blood components ( ALD , median 1 U ; and ASD , median 2 U ) than P ( median 6 U ; P = 0.001 ) , with no difference in overall complication rate . Use of aprotinin was associated with a savings in the patient charges for blood components , operating room time , and duration of hospitalization . In conclusion , aprotinin decreased the number of units of banked blood components used during the first 24 postoperative hours in reoperative pediatric OHS . Aprotinin thus decreases the risks associated with exposure to banked blood components and reduces hospital charges . ( Anesth Analg 1996;83:1193 - 9 BACKGROUND Children with cyanotic heart disease undergoing cardiac surgery in which cardiopulmonary bypass is used are at increased risk of postoperative bleeding . In this study , the authors investigated the possibility of reducing postoperative blood loss by using aprotinin and tranexamic acid alone or a combination of these two agents . METHODS In a prospect i ve , r and omized , blind study , 100 children undergoing cardiac surgery were investigated . In group 1 ( n = 25 ) patients acted as the control and did not receive either study drugs . In group 2 ( n = 25 ) patients received aprotinin ( 30.000 KIU.kg(-1 ) after induction of anesthesia , 30.000 KIU.kg(-1 ) in the pump prime and 30.000 KIU.kg(-1 ) after weaning from bypass ) . In group 3 ( n = 25 ) patients received tranexamic acid ( 100 mg.kg(-1 ) after induction of anesthesia , 100 mg.kg(-1 ) in the pump prime and 100 mg.kg(-1 ) after weaning from bypass ) . In group 4 ( n = 25 ) patients received a combination of the two agents in the same manner . Total blood loss and transfusion requirements during the period from protamine administration until 24 h after admission to the intensive care unit were recorded . In addition , hemoglobin , platelet counts and coagulation studies were recorded . RESULTS Postoperative blood loss was significantly higher in the control group ( group 1 ) compared with children in other groups who were treated with aprotinin , tranexamic acid or a combination of the two agents ( groups 2 , 3 and 4 ) during the first 24 h after admission to cardiac intensive care unit ( 40 + /- 18 ml.kg(-1).24 h(-1 ) , aprotinin ; 35 + /- 16 ml.kg(-1).24 h(-1 ) , tranexamic acid ; 34 + /- 19 ml.kg(-1).24 h(-1 ) , combination ; 35 + /- 15 ml.kg(-1).24 h(-1 ) ) . The total transfusion requirements were also significantly less in the all treatment groups . Time taken for sternal closure was longer in the control group ( 68 + /- 11 min ) compared with treatment groups 2 , 3 and 4 , respectively ( 40 + /- 18 , 42 + /- 11 , 42 + /- 13 min , P < 0.05 ) . The coagulation parameters were not found to be significantly different between the three groups . CONCLUSIONS Our results suggested that both agents were effective to reduce postoperative blood loss and transfusion requirements in patients with cyanotic congenital heart disease . However , the combination of aprotinin and tranexamic acid did not seem more effective than either of the two drugs alone BACKGROUND The majority of patients undergoing surgical treatment for ST-elevation myocardial infa rct ion receive antifibrinolytic therapy to limit blood loss . This approach appears counterintuitive to the accepted medical treatment of the same condition -- namely , fibrinolysis to limit thrombosis . Despite this concern , no independent , large-scale safety assessment has been undertaken . METHODS In this observational study involving 4374 patients undergoing revascularization , we prospect ively assessed three agents ( aprotinin [ 1295 patients ] , aminocaproic acid [ 883 ] , and tranexamic acid [ 822 ] ) as compared with no agent ( 1374 patients ) with regard to serious outcomes by propensity and multivariable methods . ( Although aprotinin is a serine protease inhibitor , here we use the term antifibrinolytic therapy to include all three agents . ) RESULTS In propensity-adjusted , multivariable logistic regression ( C-index , 0.72 ) , use of aprotinin was associated with a doubling in the risk of renal failure requiring dialysis among patients undergoing complex coronary-artery surgery ( odds ratio , 2.59 ; 95 percent confidence interval , 1.36 to 4.95 ) or primary surgery ( odds ratio , 2.34 ; 95 percent confidence interval , 1.27 to 4.31 ) . Similarly , use of aprotinin in the latter group was associated with a 55 percent increase in the risk of myocardial infa rct ion or heart failure ( P<0.001 ) and a 181 percent increase in the risk of stroke or encephalopath 
    Output:
    
There is no evidence that suggests that , compared with aprotinin , alternative antifibrinolytics such as tranexamic acid were less effective in reducing blood loss in major pediatric surgery