Modified ultrafiltration reduces postoperative blood loss and transfusions in adult cardiac surgery: a meta-analysis of randomized controlled trials.

OBJECTIVES Cardiopulmonary bypass in cardiac surgery has been associated with several deleterious effects including haemodilution and systemic inflammation. Modified ultrafiltration (MUF) has been well established in paediatric cardiac surgery in counteracting postperfusion syndrome. However, MUF is less commonly used in adult cardiac surgery. In this meta-analysis, we compared clinical outcomes in adult patients who underwent cardiopulmonary bypass with and without MUF. METHODS Electronic searches were performed using Pubmed, Ovid Medline, EMBASE and the Cochrane Library until April 2020. Selection criteria were randomized studies of adult cardiac surgery patients comparing MUF versus no MUF. Primary outcomes were postoperative mortality, haematocrit, blood transfusion, chest tube drainage, duration of intensive care unit (ICU) stay and duration of mechanical ventilation. RESULTS Thirteen randomized controlled trials were included, comprising 626 patients in the MUF group, and 610 patients in the control (no-MUF) group. There was a significantly improved postoperative haematocrit [mean difference 2.70, 95% confidence interval (CI) 0.68-4.73, P = 0.009], lower chest tube drainage (mean difference -105 ml, 95% CI -202 to -7 ml, P = 0.032), lower postoperative blood transfusion rate (mean difference -0.73 units, 95% CI -0.98 to -0.47 units, P < 0.0001) and shorter duration of ICU stay (mean difference -0.13 days, 95% CI -0.27 to -0.00 days, P = 0.048) in the MUF group. There was no difference in ventilation time (mean difference -0.47 h, 95% CI -2.05 to 1.12 h, P = 0.56) or mortality rates (odds ratio 0.62, 95% CI 0.28-1.33, P = 0.22). There were no reported complications associated with MUF. CONCLUSIONS MUF is a safe and feasible option in adult cardiac patients, with significant benefits including improved postoperative haematocrit, as well as reduced postoperative chest tube bleeding, transfusion requirements and duration of ICU stay.