***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 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: BACKGROUND : Our aim was to investigate postoperative complications and mortality after administration of aprotinin compared to tranexamic acid in an unselected , consecutive cohort . METHODS : Perioperative data from consecutive cardiac surgery patients were prospect ively collected between September 2005 and June 2006 in a university-affiliated clinic ( n = 1188 ) . During the first 5 mo , 596 patients received aprotinin  ( Group A ) ; in the next 5 mo , 592 patients were treated with tranexamic acid ( Group T ) . Except for antifibrinolytic therapy , the anesthetic and surgical protocol s remained unchanged . RESULTS : The pre- and intraoperative variables were comparable between the treatment groups . Postoperatively , a significantly higher incidence of seizures was found in Group T ( 4.6 % vs 1.2 % , P < 0.001 ) . This difference was also significant in the primary valve surgery and the high risk surgery subgroups ( 7.9 % vs 1.2 % , P = 0.003 ; 7.3 % vs 2.4 % , P = 0.035 , respectively ) . Persistent atrial fibrillation ( 7.9 % vs 2.3 % , P = 0.020 ) and renal failure ( 9.7 % vs 1.7 % , P = 0.002 ) were also more common in Group T , in the primary valve surgery subgroup . On the contrary , among primary coronary artery bypass surgery patients , there were more acute myocardial infa rct ions and renal dysfunction in Group A ( 5.8 % vs 2.0 % , P = 0.027 ; 22.5 % vs 15.2 % , P = 0.036 , respectively ) . The 1-yr mortality was significantly higher after aprotinin treatment in the high risk surgery group ( 17.7 % vs 9.8 % , P = 0.034 ) . CONCLUSION : Both antifibrinolytic drugs bear the risk of adverse outcome depending on the type of cardiac surgery . Administration of aprotinin should be avoided in coronary artery bypass graft and high risk patients , whereas administration of tranexamic acid is not recommended in valve surgery Following findings of the Clinical R and omisation of an Antifibrinolytic in Significant Haemorrhage ( CRASH-2 ) trial , tranexamic acid ( TxA ) use post trauma is becoming widespread . However , issues of generalisability , applicability and predictability beyond the context of study sites remain unresolved . Internal and external validity of the CRASH-2 trial are currently lacking and therefore incorporation of TxA into routine trauma resuscitation guidelines appears premature . The  Pre-hospital Antifibrinolytics for Traumatic Coagulopathy and Haemorrhage (PATCH)-Trauma study is a National Health and Medical Research Council-funded r and omised controlled trial of early administration of TxA in severely injured patients likely to have acute traumatic coagulopathy . The study population chosen has high mortality and morbidity and is potentially most likely to benefit from TxA 's known mechanisms of action . This and further trials involving appropriate sample population s are required before evidence based guidelines on TxA use during trauma resuscitation can be developed OBJECTIVES To characterize contemporary use of tranexamic acid ( TXA ) in combat injury and to assess the effect of its administration on total blood product use , thromboembolic complications , and mortality . DESIGN Retrospective observational study comparing TXA administration with no TXA in patients receiving at least 1 unit of packed red blood cells . A subgroup of patients receiving massive transfusion ( ≥10 units of packed red blood cells ) was also examined . Univariate and multivariate regression analyses were used to identify parameters associated with survival . Kaplan-Meier life tables were used to report survival . SETTING A Role 3 Echelon surgical hospital in southern Afghanistan . PATIENTS A total of 896 consecutive admissions with combat injury , of which 293 received TXA , were identified from prospect ively collected UK and US trauma registries . MAIN OUTCOME MEASURES Mortality at 24 hours , 48 hours , and 30 days as well as the influence of TXA administration on postoperative coagulopathy and the rate of thromboembolic complications . RESULTS The TXA group had lower unadjusted mortality than the no-TXA group ( 17.4 % vs 23.9 % , respectively ; P = .03 ) despite being more severely injured ( mean [ SD ] Injury Severity Score , 25.2 [ 16.6 ] vs 22.5 [ 18.5 ] , respectively ; P < .001 ) . This benefit was greatest in the group of patients who received massive transfusion ( 14.4 % vs 28.1 % , respectively ; P = .004 ) , where TXA was also independently associated with survival ( odds ratio = 7.228 ; 95 % CI , 3.016 - 17.322 ) and less coagulopathy ( P = .003 ) . CONCLUSIONS The use of TXA with blood component-based resuscitation following combat injury results in improved measures of coagulopathy and survival , a benefit that is most prominent in patients requiring massive transfusion . Treatment with TXA should be implemented into clinical practice as part of a resuscitation strategy following severe wartime injury and hemorrhage Background : Massive transfusion protocol s ( MTPs ) have become st and ard of care in the management of bleeding injured patients , yet strategies to guide them vary widely . We conducted a pragmatic , r and omized clinical trial ( RCT ) to test the hypothesis that an MTP goal directed by the viscoelastic assay thrombelastography ( TEG ) improves survival compared with an MTP guided by conventional coagulation assays ( CCA ) . Methods : This RCT enrolled injured patients from an academic level-1 trauma center meeting criteria for MTP activation . Upon MTP activation , patients were r and omized to be managed either by an MTP goal directed by TEG or by CCA ( ie , international normalized ratio , fibrinogen , platelet count ) . Primary outcome was 28-day survival . Results : One hundred eleven patients were included in an intent-to-treat analysis ( TEG = 56 , CCA = 55 ) . Survival in the TEG group was significantly higher than the CCA group ( log-rank P = 0.032 , Wilcoxon P = 0.027 ) ; 20 deaths in the CCA group ( 36.4 % ) compared with 11 in the TEG group ( 19.6 % ) ( P = 0.049 ) . Most deaths occurred within the first 6 hours from arrival ( 21.8 % CCA group vs 7.1 % TEG group ) ( P = 0.032 ) . CCA patients required similar number of red blood cell units as the TEG patients [ CCA : 5.0 ( 2–11 ) , TEG : 4.5 ( 2–8 ) ] ( P = 0.317 ) , but more plasma units [ CCA : 2.0 ( 0–4 ) , TEG : 0.0 ( 0–3 ) ] ( P = 0.022 ) , and more platelets units [ CCA : 0.0 ( 0–1 ) , TEG : 0.0 ( 0–0 ) ] ( P = 0.041 ) in the first 2 hours of resuscitation . Conclusions : Utilization of a goal -directed , TEG-guided MTP to resuscitate severely injured patients improves survival compared with an MTP guided by CCA and utilizes less plasma and platelet transfusions during the early phase of resuscitation Introduction Antifibrinolytic agents are commonly used during cardiac surgery to minimize bleeding . Because of safety concerns , aprotinin was withdrawn from the market in 2007 . Since then , tranexamic acid ( TXA ) has become the antifibrinolytic treatment of choice in many heart centers . The safety profile of TXA has not been extensively studied . Therefore , the aim of this study was to evaluate safety and efficiency of TXA compared with aprotinin in cardiac surgery . Methods Since July 1 , 2006 , TXA has been administered at a dose of 50 mg/kg tranexamic acid before cardiopulmonary bypass ( CPB ) and 50 mg/kg into the priming fluid of the CPB . Prior to this , all patients were treated with aprotinin at a dose of 50,000 KIU per kilogram body weight . Safety was evaluated with mortality , biomarkers , and the diagnosis of myocardial infa rct ion , ischemic stroke , convulsive seizures , and acute renal failure in the intensive care unit ( ICU ) , intermediate care unit ( IMCU ) , and hospital stay . Efficiency was evaluated by the need for transfusion of blood products and total postoperative blood loss . Results After informed consent , 893 patients were included in our data base ( 557 consecutive patients receiving aprotinin and 336 patients receiving TXA ) . A subgroup of 320 patients undergoing open-heart procedures ( 105 receiving TXA and 215 receiving aprotinin )  was analyzed separately . In the aprotinin group , a higher rate of late events of ischemic stroke ( 3.4 % versus 0.9 % ; P = 0.02 ) and neurologic disability ( 5.8 % versus 2.4 % ; P = 0.02 ) was found . The rate of postoperative convulsive seizures was increased in tendency in patients receiving TXA ( 2.7 % versus 0.9 % ; P = 0.05 ) . The use of TXA was associated with higher cumulative drainage losses ( PANOVA < 0.01 ; Ptime < 0.01 ) and a higher rate of repeated thoracotomy for bleeding ( 6.9 % versus 2.4 % ; P < 0.01 ) . In the subgroup of patients with open-chamber procedures , mortality was higher in the TXA group ( 16.2 % TXA versus 7.5 % aprotinin ; P = 0.02 ) . Multivariate logistic regression identified EURO score II and CPB time as additional risk factors for this increased mortality . Conclusions The use of high-dose TXA is question ed , as our data suggest an association between higher mortality and minor efficiency while the safety profile of this drug is not consistently improved . Further confirmatory prospect i ve studies evaluating the efficacy and safety profile of TXA are urgently needed to find a safe dosage for this antifibrinolytic drug Background In cardiopulmonary bypass ( CPB ) patients , fibrinolysis may enhance postoperative inflammatory response . We aim ed to determine whether an additional postoperative dose of antifibrinolytic tranexamic acid ( TA ) reduced CPB-mediated inflammatory response ( IR ) . Methods We performed a r and omized , double-blind , dose-dependent , parallel-groups study of elective CPB patients receiving TA .  Patients were r and omly assigned to either the single-dose group ( 40 mg/Kg TA before CPB and placebo after CPB ) or the double-dose group ( 40 mg/Kg TA before and after CPB ) . Results 160 patients were included , 80 in each group . The incident rate of IR was significantly lower in the double-dose-group TA2 ( 7.5 % vs. 18.8 % in the single-dose group TA1 ; P = 0.030 ) . After adjusting for hypertension , total protamine dose and temperature after CPB , TA2 showed a lower risk of IR compared with TA1 [ OR : 0.29 ( 95 % CI : 0.10 - 0.83 ) , ( P = 0.013 ) ] . Relative risk for IR was 2.5 for TA1 ( 95 % CI : 1.02 to 6.12 ) . The double-dose group had significantly lower chest tube bleeding at 24 hours [ 671 ( 95 % CI 549 - 793 vs. 826 ( 95 % CI 704 - 949 ) mL ; P = 0.01 corrected-P significant ] and lower D-dimer levels at 24 hours [ 489 ( 95 % CI 437 - 540 ) vs. 621(95 % CI : 563 - 679 ) ng/mL ; P = 0.01 corrected-P significant ] . TA2 required lower levels of norepinephrine at 24 h [ 0.06 ( 95 % CI : 0.03 - 0.09 ) vs. 0.20(95 CI : 0.05 - 0.35 ) after adjusting for dobutamine [ F = 6.6 ; P = 0.014 corrected-P significant].We found a significant direct relationship between IL-6 and temperature ( rho = 0.26 ; P < 0.01 ) , D-dimer ( rho = 0.24 ; P < 0.01 ) , norepinephrine ( rho = 0.33 ; P < 0.01 ) , troponin I ( rho = 0.37 ; P < 0.01 ) , Creatine-Kinase ( rho = 0.37 ; P < 0.01 ) , Creatine Kinase-MB ( rho = 0.33 ; P < 0.01 ) and lactic acid ( rho = 0.46 ; P < 0.01 ) at ICU arrival . 
    Output:
    
Although the use of prehospital TXA in the severely injured trauma patient will become more clear with the trauma studies currently underway , the current literature supports the use of prehospital TXA in this high-risk population .