Antithrombotic Drugs Have A Minimal Effect on Intraoperative Blood Loss During Emergency Surgery for Generalized Peritonitis: A Nationwide Retrospective Cohort Study In Japan

Background: The effect of antithrombotic drugs on intraoperative operative blood loss volume in patients undergoing emergency surgery for generalized peritonitis is not well defined. The purpose of this study is to evaluate whether antithrombotic drugs affect intraoperative blood loss in generalized peritonitis using a nationwide surgical registry in Japan. Method: This retrospective cohort study used a nationwide surgical registry data from 2011 to 2017 in Japan. Propensity score matching for the use of antithrombotic drugs was used for the adjustment of age, gender, comorbidities, frailty, preoperative patient’s state, types of surgery, surgical approach, laboratory data, and others. The main outcome was intraoperative blood loss: comparison of intraoperative blood loss; adjusted ratio of intraoperative blood loss after adjustment for confounding factors; variable importance of all covariates. Results: A total of 70,105 of the eligible 75,666 patients were included in this study, and 2,947 patients were taking antithrombotic drugs. Propensity score matching yielded 2,864 well-balanced pairs. There was a statistically difference in the blood loss. (antithrombotic drugs vs control: 100 [10-349] vs 70 [10-299] ml, p<0.01). After adjustment for confounding factors, the use of antithrombotic drugs was related to a 1.30-fold increase in intraoperative blood loss compared to non-use of antithrombotic drugs (95% CI, 1.16 – 1.45). The variable importance revealed that the effect of the use of antithrombotic drugs was minimal compared with surgical approach or type of surgery. Conclusion: This study shows that while taking antithrombotic drugs is associated with a slight increase in intraoperative blood loss in emergency surgery for generalized peritonitis, the difference is negligible and not clinically significant.