Comparative Study on the Effect of Dobutamine Versus Adrenaline on the Cellular Oxygen Delivery and Consumption in Open Heart Surgery

Abstract

The effect of infusion of dobutamine I 0-15 Jlg/kg/min. or adrenaline 50-200 nglkg/min. as a cardiac support after CPB (cardiopulmonary bypass), in open heart surgery, on the cellular oxygen delivery and consumption was studied. This work was done on 40 patients undergoing coronary artery graft surgery or mitral valve replacement. The patients were divided into two groups: Group 1: received 7-15 Jlg/kg/min. dobutamine infusion, while; Group II: received 50-200 nglkg/min. adrenaline infusion for each of 20 patients. The data measured after induction, 15 minutes and 30 minutes of starting the cardiac support infusion (dobutamine or epinephrine). Pulmonary artery catheterization was done in all patients. The parameters measured were HR., MAP, MPAP, RAP, CI, SVRI, Hb and arterial and mixed venous blood gas analysis. Oxygen delivery and consumption calculated by Fick's equation. It was found that in dobutamine group, the oxygen delivery (Do2) increased by 15.66% after 15 minutes and progressed to 20.13% after 30 minutes, oxygen consumption (Vo2) increased by 2% after 15 and 30 minutes while in epinephrine group the Do2 increased by 45.49% after 15 minutes and progressed to 60.66% after 30 minutes, vo2 increased by 24.67% after 15 minutes and progressed to 34.94% after 30 minutes. The oxygen extraction decreased significantly only in dobutamine group. Also lactate decreased only in dobutamine group. We concluded that as regards the cellular oxygenation dobutamine infusion, as a cardiac support after CPB, is better than epinephrine infusion.