METHODS Sixty females (mean age, 32 years) undergoing laparoscopic gynecological surgery were randomized to control group and received only the conventional anesthetic drugs and 20 ml/kg of lactated Ringer's over 30 min. The others were also given an infusion of 50 µg/kg/min of esmolol (beta1-receptor blocker) or 0.01 µg/kg/min of phenylephrine (alpha1-adrenergic agonist) over 3 hours. The distribution and elimination of infused fluid was studied by volume kinetic analysis based on urinary excretion and blood Hgb level.