The hemodynamic effects of aminophylline and salbutamol alone and in combination.

We have studied the hemodynamic effects of salbutamol and aminophylline in eight patients with obstructive airways disease. Aminophylline was administered intravenously as a bolus and an infusion for 150 minutes. Salbutamol was administered by nebulizer after 30 minutes and at the end of the infusion. Compared with placebo, salbutamol decreased ventricular afterload (decreased preinjection period and preinjection period to left ventricular ejection time ratio and diastolic blood pressure). Aminophylline decreased total electromechanical systole, corrected for heart rate, only (mean decrease -10.7 msec; range -6.5 to -15.1), indicating a mild positive inotropic effect. When both active treatments were combined, the effect on total electromechanical systole, corrected for heart rate, was potentiated (mean decrease -23.3 msec; range -19.1 to -33.1). Neither aminophylline nor the combination affected heart rate or blood pressure, suggesting no increase in myocardial oxygen consumption. The hemodynamic effects of aminophylline and salbutamol are potentiated in combination but are unlikely to be harmful in patients with obstructive airways disease.