[Ketanserin versus sodium nitroprusside in the treatment of hypertension following coronary surgery. Effect on intrapulmonary right and left shunt and arterial oxygenation].

Twenty patients requiring management of postoperative arterial hypertension following coronary artery bypass grafting (CABG) were randomly treated with either ketanserin (n = 10) or sodium nitroprusside (SNP) (n = 10). After surgery all patients were mechanically ventilated in the intensive care unit (F1O2:0.5; PEEP: +5 cm H2O). During the therapy with either drug F1O2 was adjusted to achieve normal blood oxygen tensions (F1O2 always greater than 0.3). Samples of arterial and mixed-venous blood were obtained simultaneously before administration of either drug and at each time point. Data acquisition followed over 12 h. Both drugs led to a significant decrease in arterial blood pressure, although 2 patients had to be withdrawn from the ketanserin group because there was no adequate decrease in systolic arterial pressure. A significant increase in heart rate was noted only in patients receiving SNP. In the SNP-treated patients F1O2 had to be increased because of a marked decrease in paO2, resulting in a significant increase in alveolar-arterial oxygen difference (A-aDO2). In 3 patients SNP had to be stopped because of an increase in intrapulmonary shunt (Qsp/Qt) more than 30%. No significant changes in Qsp/Qt, A-aDO2, or paO2 were seen in the ketanserin-treated patients.