This study was designed to compare the effect of low-molecular 6% hydroxyethyl starch (HES) 130/0.4 on hemostasis and hemodynamic efficacy with that of medium-molecular 6% HES 200/0.5 in patients undergoing off-pump coronary artery bypass surgery.

Forty-eight patients were randomized to receive up to 33 ml/kg of either 6% HES 130/0.4 or 6% HES 200/0.5. Hemodynamic variables and blood tests including thromboelastography were measured 10 min after induction (baseline value, T0), 5 min after acute loading of HES 10 ml/kg (T1) in hypovolemic patients, after sternum closure (T2), and 16 hr after intensive care unit (ICU) arrival (T3). Chest tube drainage was recorded until 16 hours after ICU arrival.

Hemodynamic variables were similar in both groups. Chest tube drainage at 16 hr after surgery was higher in HES 200/0.5 group than that in HES 130/0.4 group. Maximum clot firmness was decreased in HES 200/0.5 group at sternal closure but not in HES 130/0.4 group.

Both HES 200/0.5 and HES 130/0.4 were equally efficient in maintaining stable hemodynamics during off-pump coronary artery bypass surgery. However, HES 130/0.4 may reduce postoperative blood loss compared to that of HES 200/0.5 at the same dose of 33 ml/kg.