***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 Diffuse microvascular bleeding remains a common problem after cardiac procedures .Systemic use of antifibrinolytic reduces the postoperative blood loss . The purpose of this study was to examine the effectiveness of local application of tranexamic acid to reduce blood loss after coronary artery bypass grafting ( CABG ) . Methods Thirty eight patients scheduled for primary isolated coronary artery bypass grafting were included in this double blind , prospect i ve , r and omized , placebo controlled study .Tranexamic acid ( TA ) group ( 19 patients ) received 1 gram of TA diluted in 100 ml normal saline . Placebo group ( 19 patients ) received 100 ml of normal saline only . The solution was purred in the pericardial and mediastinal cavities . Results Both groups were comparable in their baseline demographic and surgical characteristics . During the first 24 hours post-operatively , cumulative blood loss was significantly less in TA group ( median of 626 ml ) compared to Placebo group ( median of 1040 ml ) ( P = 0.04 ) . There was no significant difference in the post-op Packed RBCs transfusion between both groups ( median of one unit in each ) ( P = 0.82 ) . Significant less platelets transfusion required in TA group ( median zero unit ) than in placebo group ( median 2 units ) ( P = 0.03 ) . Apart from re-exploration for excessive surgical bleeding in one patient in TA group , no difference was found in morbidity or mortality between both groups . Conclusion Topical application of tranexamic acid in patients undergoing primary coronary artery bypass grafting led to a significant reduction in postoperative blood loss without adding extra risk to the patient This prospect i ve r and omized study analyses the use of a prescribed 4.8 % tranexamic acid post-operative mouthwash over 2 days vs 5 days to prevent bleeding in patients taking warfarin who require dental extraction s. Eighty-five patients therapeutically anticoagulated with warfarin for various conditions , ranging in age from 21 to 86 years and requiring dental extraction s , were r and omly divided into two groups . Group A postoperatively received a 4.8 % tranexamic acid mouthwash to be used over a 2-day period . Group B received the same mouthwash and instructions postoperatively , to be taken over 5 days . All procedures were performed on an ambulatory basis under local anaesthetic by the same surgeon . Patients were review ed 1 , 3 , and 7 days postoperatively to assess bleeding . Eighty-two of the 85 patients encountered no postoperative problems . Two patients in group A and one in group B had minor postoperative bleeds that required minor ambulatory intervention to control . This study shows that a 2-day postoperative course of a 4.8 % tranexamic acid mouthwash is as equally effective as a 5-day course in controlling haemostasis post-dental extraction s in patient 's anticoagulated with warfarin Purpose The surgical stress of total knee arthroplasty ( TKA ) procedure and the application of intra-operative pneumatic thigh tourniquet increases local fibrinolytic activity , which contributes significantly to post-operative blood loss .  Tranexamic acid , an antifibrinolytic drug , is commonly used to control post-operative blood loss . The recommended mode of administration of tranexamic acid is either oral or intravenous . However , the mechanism of action of the tranexamic acid points towards the possible effectiveness it may have following local/intra-articular application . This prospect i ve , double-blinded , r and omized preliminary study evaluated the efficacy of intra-articular tranexamic acid in reducing TKA-associated post-operative blood loss . Methods Fifty consenting patients with osteoarthritis of the knee scheduled for primary unilateral cemented-TKA were r and omly allocated to one of the two groups : Tranexamic Acid ( TA ) group ( n = 25 , 500 mg/5 ml tranexamic acid ) and the control group ( n = 25 , 5 ml 0.9 % saline ) . The drug and control solution were administered intra-articularly through the drain tube immediately after the wound closure . Parameters related to blood loss ( drop in haemoglobin , haematocrit differential ) and the drain output [ volume ( ml ) ] were compared between the two groups . Results On a comparative basis , TA-group obtained significant reduction in the drain output [ 95 % CI : 360.41–539.59 , p < 0.001 ] at 48 h post-operatively . Even though the control group received sixfold more blood transfusion than TA-group , it showed a greater drop in haemoglobin and haematocrit ( p < 0.05 ) . Conclusions Local application of tranexamic acid seems to be effective in reducing post-TKA blood loss as well as blood transfusion requirements . Level of evidence Therapeutic study , Level II Background The antifibrinolytic tranexamic acid reduces surgical blood loss , but studies have not identified an optimal regimen . Questions / purpose sWe studied different dosages , timings , and modes of administration to identify the most effective regimen of tranexamic acid in achieving maximum reduction of blood loss in TKA . Methods We prospect ively studied five regimens ( four intravenous , one local ; 40 patients each ) with a control group ( no tranexamic acid ) . The four intravenous ( 10-mg/kg dose ) regimens included ( 1 ) intraoperative dose ( IO ) given before tourniquet deflation , ( 2 ) additional preoperative dose ( POIO ) , ( 3 ) additional postoperative dose ( IOPO ) , and ( 4 ) all three doses ( POIOPO ) . The fifth regimen was a single local application ( LA ) . Two independent parameters of drain loss and total blood loss , calculated by the hemoglobin balance method , were evaluated statistically . Results Both parameters were reduced in all five regimens as against the control . A significant reduction in drain loss was seen in the POIO , IOPO , and POIOPO groups whereas total blood loss was significantly reduced in the POIO , POIOPO , and LA groups . The POIOPO group had the least drain loss ( 303 mL ) and least total blood loss ( 688 mL ) . The IO group had the greatest drain loss and the IOPO group the greatest total blood loss . Conclusions Single-dose tranexamic acid did not give effective results . The two-dose regimen of POIO was the least amount necessary for effective results . When compared against the control , this regimen produced reduction of drain loss and total blood loss , whereas the IOPO regimen did not . The three-dose regimen of POIOPO produced maximum effective reduction of drain loss and total blood loss . Level of Evidence Level I , therapeutic study . See Guidelines for Authors for a complete description of levels of evidence OBJECTIVE Postoperative bleeding is still one of the most common complications of cardiac surgery . Antifibrinolytic agents successfully reduce bleeding , but there are controversies concerning adverse effects after their systemic use . By topical application of antifibrinolytic agents in pericardial cavity , most of these effects are avoided . We compared the effects of topically applied aprotinin , tranexamic acid and placebo on postoperative bleeding and transfusion requirements . METHODS In this single-center prospect i ve , r and omized , double-blind trial , 300 adult cardiac patients were r and omized into three groups to receive one million IU of aprotinin ( AP group ) , 2.5 g of tranexamic acid ( TA group ) or placebo ( PL group ) topically before sternal closure . Groups were comparable with respect to all preoperative and intraoperative variables . Postoperative bleeding , transfusion requirements and hematologic parameters were evaluated . RESULTS Postoperative bleeding within first 12-h period ( AP group 433+/-294 [ 350 ; 360]ml , TA group 391+/-255 [ 350 ; 305]ml , PL group 613+/-505 [ 525 ; 348]ml ) , as well as cumulative blood loss within 24h ( AP group 726+/-432 [ 640 ; 525]ml , TA group 633+/-343 [ 545 ; 335]ml , PL group 903+/-733 [ 800 ; 445]ml ) , showed statistically significant inter-group differences ( both p<0.001 ) . Bleeding rates values were significantly higher in placebo group compared to the groups treated with antifibrinolytic agents ( AP and TA groups ) concerning both variables . Although TA group showed the lowest values , no statistical differences between TA and AP groups were found . Inter-group difference of blood product requirements was not statistically significant . CONCLUSIONS Topical use of either tranexamic acid or aprotinin efficiently reduces postoperative bleeding .  TA seems to be at least as potent as aprotinin , but potentially safer and with better cost-effectiveness ratio A high-dose local tranexamic acid has been introduced in total knee arthroplasty for bleeding control . We are not sure about the systemic absorption and side effects . The aim of this study was to evaluate the effect of low dosage of intra-articular tranexamic acid injection combined with 2-hour clamp drain in minimally bleeding computer-assisted surgery total knee replacement ( CAS-TKR ) . A prospect i ve r and omized controlled trial was conducted in a total of 48 patients underwent CAS-TKR . The patients were r and omly assigned to receive either of a mixed intra-articular solution of tranexamic acid 250 mg with physiologic saline ( TXA group ) , or physiologic saline ( control group ) and then followed by clamp drain for 2 hours .  Postoperative blood loss was measured by three different methods as drainage volume , total hemoglobin loss and calculated total blood loss . Transfusion requirement and postoperative complications were recorded . All patients were screened for deep vein thrombosis and the functional outcomes were evaluated at 6 months after surgery . The mean postoperative drainage volume , total hemoglobin loss and calculated total blood loss in TXA group were 308.8 mL , 2.1 g/dL and 206.3 mL compared to 529.0 mL , 3.0 g/dL and 385.1 mL in the control group ( P=0.0003 , 0.0005 and < 0.0001 respectively ) . Allogenic blood transfusion was needed for one patient ( 4.2 % ) in TXA group and for eight patients ( 33.3 % ) in the control group . Postoperative knee scores were not significantly different between groups . No deep vein thrombosis , infection or wound complication was detected in both groups . In this study , low dose intra-articular tranexamic acid injection combined with 2-hour clamping drain was effective for reducing postoperative blood loss and transfusion requirement in CAS-TKR without significant difference in postoperative complications or functional outcomes Background and objective : Cardiopulmonary bypass is known to induce postoperative coagulopathy including fibrinolysis . We have evaluated the effect of the topical use of tranexamic acid in the pericardial cavity on postoperative bleeding following open heart surgery . Methods : One hundred patients , scheduled for elective open heart surgery , were included in this double‐blind , prospect i ve , r and omized , controlled study . They were allocated to a treatment group ( Group I ) , or placebo group ( Group II ) . Patients with coagulopathies , renal failure , re‐do surgery , or recent anti‐platelet treatment were excluded . In Group I , tranexamic acid ( 2 g in 100 mL of saline solution ) was poured into the pericardial cavity before sternal closure . Placebo patients received 100 mL of saline . Postoperative blood loss , need for transfusion of blood products and the rate of re‐sternotomy for bleeding were documented . Results : During the first postoperative 24 h , cumulative blood loss was significantly higher in Group II compared to Group I ( 1208 ± 121 mL vs. 733 ± 93 mL , respectively ) ( P < 0.001 ) . More blood transfusions were administered to Group II patients ( 4.54 ± 1.4 units ) as compared to Group I patients ( 2.64 ± 1.5 units ) ( P < 0.01 ) . Conclusion : Topical application of tranexamic acid in patients undergoing primary open heart surgery led to a significant reduction of both postoperative mediastinal bleeding , and rate of re‐exploration for haemostasis We carried out a placebo-controlled , double-blind , r and omized study of the hemostatic effect of tranexamic acid mouthwash after oral surgery in 39 patients receiving anticoagulant agents because of the presence of cardiac valvular stenosis , a prosthetic cardiac valve , or a vascular prosthesis . Surgery was performed with no change in the level of anticoagulant therapy , and treatment with the anticoagulant agent was continued after surgery . Before it was sutured , the operative field was irrigated in 19 patients with 10 ml of a 4.8 percent aqueous solution of tranexamic acid ( an inhibitor of fibrinolysis ) and in 20 patients with a placebo solution . For seven days thereafter , patients were instructed to rinse their mouths with 10 ml of the assigned solution for two minutes four times a day . There were no significant differences between the two treatment groups in base-line variables , including the level of antico 
    Output:
    
There is reliable evidence that topical application of tranexamic acid reduces bleeding and blood transfusion in surgical patients , however the effect on the risk of thromboembolic events is uncertain .