Résumé : In this prospective, randomized, open controlled study we compared the effects on net red blood cell loss of 6% hydroxyethyl starch 130/0.4 (HES: n = 64) and 3% modified fluid gelatin (GEL: n = 68) administered for intravascular volume management in patients undergoing coronary surgery. Blood losses were calculated from determination of circulating blood volume and measurement of preoperative and postoperative hematocrit. Amount of colloids that could be administered was limited to 50 mL/kg. If additional fluids were required, balanced crystalloid solution was used. Anesthetic and surgical techniques were standardized. Both groups were similar with regard to demographic and intraoperative variables. Total study drug was 48.9 ± 17.2 mL/kg in the HES group and 48.9 ± 14.6 mL/kg in the GEL group. Total red blood cell loss was 544 ± 305 mL in the HES group and 504 ± 327 mL the GEL group. Measured blood losses were also similar in both groups (HES, 19.4 ± 12.3 mL/kg; GEL, 19.2 ± 14.5 mL/kg). Exposure to allogeneic blood product was comparable in both groups. In the conditions of the present study, HES 130/0.4 up to 50 mL/kg is a valuable alternative to modified fluid gelatin for plasma volume expansion during and after cardiac surgery. ©2005 by the International Anesthesia Research Society.