RESUMO
The combined use of phenoxybenzamine and dopamine was applied in infants and children when it was difficult to come off cardiopulmonary bypass for low cardiac output. The rationale of this method is to prevent the alpha-adrenergic action of dopamine by phenoxybenzamine and to encourage the beta-adrenergic and direct specific action of dopamine. Dopamine was used in dosage of 10 to 30 micrograms/kg per min after the additional administration of a half of the initial dosage of phenoxybenzamine; this was infused by drip always in a dosage of 0.5 to 1.0 mg/kg during the first half of cardiopulmonary bypass. It was possible to come off cardiopulmonary bypass with a stable haemodynamic state (mean arterial pressure more than 60 mmHg and total peripheral vascular resistance less than 2000 bynes s cm-5) and a good urinary output.