[Effects of dopamine and dobutamine on systemic hemodynamics and myocardial metabolism in children after open heart surgery].

The purpose of this study is to know the effects of Dopamine (DOA) and Dobutamine (DOB) on the systemic hemodynamics and myocardial metabolism in the acute phase after open heart surgery in children. Thirty patients with congenital heart disease were divided into following two groups. The first 14 cases were administered 5 and 10 micrograms/kg/min (gamma) of DOA, and the systemic hemodynamic and metabolic data were taken before and after the administration of the drug. The second 12 cases were given the same doses of DOB instead of DOA. DOA: The blood pressure was elevated by 10 gamma of DOA, and cardiac index (CI) and stroke volume index (SVI) rose up at both doses of DOA. On the other hand, systemic vascular resistance (SVR) and left atrial pressure (LAP) were decreased at both dosage levels. DOB: At the same dose of DOA, DOB increased HR and SVI, so CI rose up markedly. The systolic and mean blood pressure also rose up at both doses. CVP and LAP were depressed at either dosage level. SVR did not show an appreciable change. Myocardial metabolism: The two drugs tested did not exhibit the progress of anaerobic myocardial metabolism. The myocardial oxygen uptake rate increased with DOA, but decreased with DOB. This phenomena probably suggests that DOB dilates coronary vascular bed. From the above data, the following effects are expected by the use of each drug after open heart surgery in children: 1) an increase of cardiac output due to inotropic action by DOA, 2) powerful inotropic and chronotropic action by DOB.