Influence of colloid infusion on coagulation during off-pump coronary artery bypass grafting

This study was conducted to determine the influence of colloid infusion on coagulation in patients undergoing off-pump coronary artery bypass grafting (OP-CABG). Thirty patients undergoing elective OP-CABG received medium molecular weight hydroxyethyl starch group I (MMW-HES 200/0.5), low molecular weight hydroxyethyl starch group II (LMW-HES 130/0.4) or gelatin group III (GEL) in a prospective randomized trial. Blood samples were assessed for haemoglobin (Hb), activated coagulation time (ACT), prothrombin time (PT), activated partial thromboplastin time (aPPT), platelet count, fibrinogen and von Willebrand factor (vWF) at specified intervals. Total volume of the colloid infused and postoperative chest-time drainage was also measured. There was a significant decrease in Hb, platelet count, fibrinogen levels in all these groups, which did not warrant blood transfusion. After the colloid infusion, vWF decreased significantly to 67% from baseline in group I as compared to 85 and 79% in group II and group III, respectively. vWF levels remained lower than the baseline value in the first 24 hours in group I, whereas this factor level increased above the baseline values in groups II and III, 6 hours postoperatively. Postoperative chest tube drainage in 24 hours was significantly higher in group I (856 +/- 131 ml) as compared to group II (550 +/- 124 ml) and group III (582 +/- 159 ml). LMW-HES 130/0.4 was superior to MMW-HES 200/0.5 and gelatin in patients undergoing OP-CABG, in terms of better preservation of coagulation associated with enhanced volume effect.