EFFECT OF DOBUTAMINE ON OXYGEN SUPPLY AND UPTAKE IN HEALTHY VOLUNTEERS

We have measured the changes in Vo₂ and the Vo₂; D_o2 relationshipduringinfusion of dobutamine in healthy volunteers. Nine healthy,adult, non-obese, male physicians were infused with an incrementalinfusion of dobutamine starting at 2.5 µg kg^–1 min^–1increasing to 5.0 and then 7.5 y.g kg^–1 min^–1 for15 min each. Vo ₂ and cardiac index were measured every fiveminutes. Vo₂/(VO₂ m^–2) increased from a baseline of 128(SEM 6.1) ml min^–1 m^–2 to 159 (8.0)ml min¹ m^–2(P< 0.05) at 7.5 fig kg^–1 min^–1. The correspondingchanges for Do₂l (Do₂m^–2) were from 643 (35) ml min^–1m^–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,range from 0.89 to 0.99 (mean 0.95, SD 0.03). Dobutamine haspotent calorigenic effects; demonstration of a positive correlationbetween Vo₂ and Do₂ after infusion of dobutamine does not necessarilyimply an underlying tissue oxygen debt.