Effect of dobutamine in postperfusion cardiac failure in the dog

The effect of dobutamine on cardiac function of dogs was investigated. Sixteen dogs were submitted to cardiopulmonary bypass. The aorta of each dog was cross-clamped for 1 hour; attempt was not made to perfuse the heart. After 1 hour, 8 of the 16 dogs were randomly selected and treated with dobutamine (5 mug/kg/min). The other 8 dogs were designated the control group and were given placebo. Postperfusion failure and death were used as end point criteria. Dogs given dobutamine responded remarkably well, with significantly decreased postperfusion low output syndrome. Evidence of cardiac function 5 minutes after the removal of the bypass was the criterion used to determine survival of the surgical cross-clamp procedure; however, this did not necessarily indicate survival of the dog. Of the 8 dogs given dobutamine, 6 (75%) survived the surgical cross-clamp, whereas of the 8 dogs not given dobutamine, 3 (37.5%) survived the surgical procedure. Seemingly, the effect of dobutamine is not mainly chronotropic, but is rather a direct aid to myocardial strength.