Nineteen patients, who developed symptomatic vasospasm due to subarachnoid hemorrhage, were treated by hypervolemic-hyperdynamic therapy. The object of this treatment was to increase cardiac output and cerebral blood flow as a result of hypervolemia and the administration of beta-stimulants. During the treatment, if cerebral infarction occurred followed by brain edema, we applied oncotic therapy. As the parameters of therapy, we measured serum colloid oncotic pressure and cardiac functions in all of these patients. Nineteen patients were divided into two groups: group A, 9 patients, who did not develop brain edema, and group B, 10 patients, who developed brain edema. All patients underwent acute neck clipping surgery and plasma volume expansion by the infusion of albumin and/or low molecular weight dextran (LMWD). If symptomatic vasospasm occurred, a Swan-Ganz catheter was inserted and cardiac output was measured until it increased to 1.5 times the value of pretreatment. In group B, we also used oncotic therapy, raising serum oncotic pressure higher than 25 mmHg by increasing the amount of albumin and/or LMWD and administering furosemide. By this treatment, the percentage of patients who showed neurological improvement in at least one deficit was 100% in group A, and 89% in group B. In Glasgow outcome scale scores, 89% of group A and 70% of group B had disability not lower than moderate. Serum colloid oncotic pressure was maintained at around 20-25mmHg in group A, and 25-30mmHg in group B. Although pulmonary artery diastolic pressure in group B tended to be lower than that in group A, cardiac indices in both groups were high, approximately 5.0 L/min/m2.(ABSTRACT TRUNCATED AT 250 WORDS)