Background and Goal of Study: In recent years there has been a growing interest in patient blood management program (PBM) to reduce allogeneic transfusions and its deleterious effects. Tranexamic acid (TXA) has demonstrated the reduction of blood loss and transfusion in total knee arthroplasty (TKA). The aim of this study is to compare the efficacy in reducing blood loss and transfusion of adding a second dose of TXA three hours after surgery, and its impact on outcomes.
Materials and Methods: A prospective, double-blind, placebo-controlled clinical trial (EudraCT:2016- 000071-24) was conducted on 99 adult patients scheduled for unilateral TKA with tourniquet, in Hospital del Mar between April 2016 to November 2017. Patients were randomized into two groups: Group 1 received an only intraoperative dose of TXA (15 mL/Kg) while Group 2 received an additional second
dose of TXA (10 mL/Kg) 3 hours after surgery. Blood loss was measured in terms of haemoglobin (Hb) at 24h and discharge, visible drain blood loss (ml), calculated blood loss (ml) and transfusion. Complications were collected within up to 30 days post-surgery. Both groups were compared using Chi squared for qualitative variables and T-student for continuous variables. Statistical significance was considered when p < 0.05.
Results and Discussion: Both groups were comparable according to gender, age, weight, surgery duration, ASA, preoperative hemoglobin (Hb) and type of anaesthesia.  Results of the study between both groups (Group 1 one TXA dose= 51 patients; Group 2 second TXA dose = 48 patients)  are the following:
24h Hb (g/dL) 11.60 ± 1.26 in Group 1 vs  12.01±1.20 in Group 2 (p= 0.09); Visible blood loss (ml) 185.37±132.01 vs 168.96±128.94 (p= 0.53); Hb discharge (g/dL) 10.32±1.20  vs 10.92±1.06 (p= 0.01); Calculated blood loss (ml)  1674.88±604.80 vs 1482.73±520.70 (p= 0.09); transfusion (%) 1 vs 0 (p=0.33).
Conclusion(s): The administration of a second dose of TXA after surgery showed a clear reduction in blood loss, but our our findings only showed a statistically significant higher Hb at discharge (this may be due to an insufficient sample size). Nevertheless, clinical relevance was low as there was no impact on transfusion or outcomes.

02 / Clinical relevance of postoperative second dose of tranexamic acid in total knee arthroplasty surgery. Preliminary results of a clinical assay.