EFFECT OF DOBUTAMINE ON OXYGEN-SUPPLY AND UPTAKE IN HEALTHY-VOLUNTEERS

We have measured the changes in VO2 and the VO2: DO2 relationship during infusion of dobutamine in healthy volunteers. Nine healthy, adult, non-obese, male physicians were infused with an incremental infusion of dobutamine starting at 2.5-mu-g kg-1 min-1 increasing to 5.0 and then 7.5-mu-g kg-1 min-1 for 15 min each. VO2 and cardiac index were measured every five minutes. VO2/(VO2 m-2) increased from a baseline of 128 (SEM 6.1) ml min-1 m-2 to 159 (8.0) ml min-1 m-2 (P < 0.05) at the end of infusion with 7.5-mu-g kg-1 min-1. The corresponding changes for DO2/(DO2 m-2) were from 643 (35) ml min-1 m-2 to 1240 (142)ml min-1 m-2 (P < 0.05). The coefficient of correlation for pairs of VO2 and DO2 values, at baseline and each dobutamine infusion in individual subjects, ranged from 0.89 to 0.99 (mean 0.95, SD 0.03). Dobutamine has potent calorigenic effects; demonstration of a positive correlation between VO2 and DO2 after infusion of dobutamine does not necessarily imply an underlying tissue oxygen debt.