Forty-six patients with severe pulmonary insufficiency were prospectively studied to compare the effects of resuscitation with either crystalloid or colloid. By random number, 26 patients received RL and 20 patients received 5 per cent ALB to maintain hemodynamic stability. Groups were comparable with respect to the cause of pulmonary insufficiency, age and sex. For the duration of the study and at 48 hours, there was no statistically significant difference between groups with respect to the following: cardiac index, colloid osmotic pressure (COP), pulmonary capillary wedge pressure (PCWP), COP-PCWP gradient, right and left ventricular stroke work indices, and amount of constant positive airway pressure required for treatment. Both groups had a significant improvement in intrapulmonary shunt (Qs/Qt) after 24 hours of treatment. The Qs/Qt in the ALB group was significantly lower than the RL group at the termination of the study, but this did not affect outcome. The RL group required more fluid than the ALB group, but the difference was not statistically significant. No clinical advantage was found for either solution in this study.