Background and Goal of Study
Tranexamic acid (TXA) appears to reduce perioperative blood loss and transfusion requirements in major orthopaedic surgery. In our hospital, a TXA protocol for administration in elective primary total hip arthroplasty (PTHA) and revision total hip arthroplasty (RTHA) was implemented a year ago. It consists in 1g of TXA IV 15 min prior to incision, and the same dose repeated three to twelve hours after surgery if bleeding exceeds 500mL We aim to audit protocol implementation to investigate if haemoglobin variation and transfusion requirements lowered with protocol employment.

Materials and Methods
Retrospective cohort study of patients submitted to PTHA and RTHA during an one-year period. We revised 286 clinical records and excluded 30 patients who had (1) no postoperative haemoglobin control, (2) unknown TXA doses or (3) timing, doses or route administration not according to the protocol. Of the 256 patients included, 206 underwent PTHA and the remaining 50 were submitted to RTHA.

We compared transfusion requirements and postoperative haemoglobin drop in the TXA group vs the No TXA group in PTHA and RTHA patients (110 vs. 96 patients and 11 vs. 39 patients, respectively).

SPSS version 22 was used for all statistical analysis, and a p-value < 0,05 significance level was used for all statistical hypothesis tests. Fisher’s exact test, chi-square test and U Mann-Whitney test were used when appropriate.

TXA administration was guided by the anaesthesiologist’s clinical judgement and by the protocol’s exclusion criteria.

Results and Discussion
In PTHA patients, the mean postoperative haemoglobin drop was significantly lower in the TXA group compared with the No TXA group (3,1±1,2 g/dL vs. 4,0±1,6 g/dL, p<0,0001). The transfusion rate was also significantly lower for the TXA group compared with the No TXA group (17,3% vs. 45,8%; p<0,0001).

In RTHA patients, both mean postoperative haemoglobin drop and transfusion requirements were lower in TXA group vs. No TXA group. However, that difference did not reach statistical significance (2,9±0,9 g/dL vs. 3,2±1,8 g/dL, p<0,761; 45,5% vs. 59%; p=0,425).

Conclusions
TXA administration in PTHA appears to reduce both postoperative haemoglobin drop and transfusion requirements so, we recommend the use of TXA in PTHA. A larger sample should be considered to access the role of TXA in RTHA.

05 / Tranexamic acid and transfusion requirements in primary and revision total hip arthroplasty