S2777 The Safety and Efficacy of Hypovolemic Phlebotomy on Blood Loss and Transfusion in Liver Surgery: A Meta-Analysis of Randomized Controlled Trials

Introduction: Effective strategies to minimize blood loss and transfusion during liver resection are limited by weak clinical evidence. Hypovolemic phlebotomy, a technique involving controlled venous drainage to reduce hepatic venous pressure, is a promising technique, but prior randomized trials were small and underpowered. The recent PRICE-2 trial provides robust data, to strengthen the evidence of this intervention. We conducted this meta-analysis to provide a comprehensive update on the efficacy and safety of hypovolemic phlebotomy in liver surgery, aiming to clarify its clinical utility. Methods: A PRISMA-guided meta-analysis was conducted using randomized trials comparing hypovolemic phlebotomy to standard of care in liver surgery. MEDLINE, Embase, and Cochrane databases were searched. Primary outcomes was blood loss. Secondary outcomes were packed red blood cell (pRBC) transfusion, complications and mortality. The risk of bias in included studies was assessed using the revised Cochrane “Risk of Bias” tool for RCTs (RoB 2.0). Data was pooled using a random-effects model, with risk ratios (RR) as the effect measure for dichotomous outcomes and mean difference (MD) as the effect measure for continuous outcomes. Results: Four randomized trials including 607 patients were included. Hypovolemic phlebotomy led to a significant reduction in intraoperative blood loss (MD −126.11 mL; 95% CI −225.42 to −26.8). Rates of pRBC transfusion (RR: 0.74; 95% CI: 0.22–2.45), major complications (RR: 0.98; 95% CI: 0.66–1.47), overall complications (RR: 0.88; 95% CI: 0.55–1.40), and mortality (RR: 2.00; 95% CI: 0.19–20.93) were similar between groups, with no statistically significant differences observed. Conclusion: Hypovolemic phlebotomy significantly reduces blood loss in liver surgery without increasing complications or mortality. While no clear effect on transfusion rates was observed, its safety and blood-sparing effect support its use as a valuable intraoperative strategy.