OXYGEN-UPTAKE SUPPLY DEPENDENCY - EFFECTS OF SHORT-TERM DOBUTAMINE INFUSION

The present study explored the possibility of using a short-term dobutamine infusion to disclose oxygen uptake/supply dependency. The effects of a standard dose of 5 μg/kg/min of dobutamine on oxygen-derived variables were studied in 73 acutely ill patients with heart failure (n = 24) or sepsis (n = 49). In each group, patients were separated according to their blood acetate concentrations (either above or below 2 mEq/L). In all patient groups, dobutamine resulted in significant increases in cardiac output and oxygen transport. However, oxygen consumption increased significantly only in patients with elevated blood lactate levels (cardiac failure: from 108 ± 26 to 131 ± 25 ml/min/M2, n = 8, p<0.01; sepsis: from 139 ± 44 to 167 ± 68 ml/min/M2; n = 16, p<0.01) and not in the other patients (heart failure: from 121 ± 29 to 115 ± 31 ml/min/M2, n = 28, NS; sepsis: from 158 ± 39 to 166 ± 45 ml/min/M2, n = 21, NS). These data, therefore, indicate that dobutamine at the dose used does not increase oxygen consumption in critically ill patients unless there is coexistent tissue hypoxia reflected by increased blood lactate levels. A short-term dobutamine infusion can be used to disclose an oxygen uptake/supply dependency phenomenon.