Remote ischemic conditioning reduces postoperative bleeding in adult cardiac surgical patients: a systematic review and meta-analysis

INTRODUCTION: The current study was designed to systemically investigate the impact of RIC on intra- and postoperative bleeding and transfusion in patients undergoing cardiac surgery. EVIDENCE ACQUISITION: We included all randomized controlled trials (RCTs) comparing RIC with control on intra- and postoperative blood loss and blood transfusion. The inclusion criteria were as follows: 1) adult patients undergoing cardiac surgery; 2) RCT; 3) perioperative administration of RIC compared to control; 4) outcomes of interest reported. Exclusion criteria included: 1) case reports, reviews, or abstracts; 2) animal or cell studies; 3) duplicate publications; 4) studies lacking information about outcomes of interest. EVIDENCE SYNTHESIS: Databases search yielded 24 RCTs including 3530 patients, 1765 patients were allocated into RIC group and 1765 into control group. The current study suggested that RIC administration was associated with reduced postoperative blood loss (WMD=-57.89; 95% CI: -89.89 to -25.89; P=0.0004). RIC did not affect the incidence of intraoperative blood loss (WMD=-4.02; 95% CI: -14.09 to 6.05; P=0.43), the volume of intra- and postoperative transfusion of RBC (WMD=-15.66; 95% CI: -39.35 to 8.03; P=0.20), the re-exploration for bleeding (WMD=-0.01; 95% CI: -0.03 to 0.01; P=0.21). CONCLUSIONS: RIC might reduce postoperative blood loss in adult cardiac surgical patients and reduced intraoperative RBC transfusion in patients undergoing coronary artery bypass grafting. However, RIC did not influence intraoperative bleeding, the volume of re-exploration for bleeding or blood transfusion postoperatively.