Thromboelastometry-guided post-bypass blood product management significantly reduced postoperative bleeding ( 9 vs 16 ml kg ( -1 ) , P < 0.001 ) and packed red cell transfusion requirement ( 11 vs 23 ml kg ( -1 ) , P = 0.005 ) at 12 h after surgery , and duration of critical care stay ( 60 vs 71 h , P = 0.014 ) .