The haemodynamic effects of a continuous intravenous infusion of salbutamol (15 to 30 'g/min) and nitroprusside (50 to 100 tug/min) were compared in 9 patients after cardiac surgical operations. The mean falls in left atrial pressure and systemic vascular resistance were similar with the two drugs but salbutamol caused a greater increase in heart rate, maximum acceleration of aortic bloodflow, and maximum rate of change of left ventricular power. Because these differences would cause greater myocardial oxygen consumption with salbutamol and because the infusion of salbutamol is less easily controlled, nitroprusside is the preferred drug after cardiac operations.Drugs that cause vasodilatation and consequently a reduction in systemic vascular impedance (left ventricular afterload) have recently been advocated in a variety of circumstances in which cardiac function is abnormal. Advantageous effects have been reported in patients with acute myocardial infarction (Chatterjee et al., 1973), chronic ischaemic heart disease (Miller et al., 1975), refractory heart failure (Guiha et al., 1974), mitral regurgitation and stenosis (Goodman et al., 1974;Bolen et al., 1975), and cardiomyopathy (Rossen et al., 1976 The present study was undertaken to measure the haemodynamic changes during a continuous intravenous infusion of salbutamol in patients soon after cardiac operations. A comparison was made with the effects of an infusion of nitroprusside because this drug has previously been recommended in similar circumstances (Stinson et al., 1975). MethodsNine patients (7 male, 2 female; age range 36 to 64 years, mean 51 years) were studied. Five had aortocoronary bypass grafts inserted and 2 had had aortic and 2 mitral valve replacement. The patients were unselected consecutive surgical candidates in whom preoperative catheterisation had excluded left ventricular dyskinesia or valve disease other than that for which the operation was being performed. The exact nature of the investigation was explained to the patients in order to obtain informed consent.The study began 24 to 36 hours after operation, at a time when the patients could be maintained for several hours in quiet undisturbed circumstances. During this period no additional drugs were given.One patient was receiving an inotropic agent (iso.

No abstract

No abstract

No abstract

No abstract