DOBUTAMINE IMPROVES GASTROINTESTINAL MUCOSAL BLOOD-FLOW IN A PORCINE MODEL OF ENDOTOXIC-SHOCK

Objective: To test the hypothesis that saline solution plus dobutamine increases gastrointestinal mucosal perfusion better than saline solut ion alone in a model of endotoxic shock. Design: Prospective, randomiz ed, unblinded study. Setting: Animal research laboratory affiliated wi th a university teaching hospital. Subjects: Twelve female pigs, weigh ing 30 to 32 kg. Interventions: Animals were anesthetized, and their l ungs were mechanically ventilated, Catheters were inserted into the ri ght atrium, pulmonary artery, and carotid artery for blood sampling an d blood pressure and cardiac output measurements, A tonometer and a la ser Doppler probe were placed in the lumen of the stomach and the ileu m for determination of mucosal acid base status and measurement of muc osal blood flow, Group 1 animals (n = 6) received an infusion (T = 0 m in) of 150 mu g/kg Escherichia coli endotoxin and normal saline soluti on (0.3 mL/kg/min), Group 2 animals (n = 6) received an infusion of en dotoxin and were resuscitated with the same method as used in group 1, but an infusion of dobutamine (5 mu g/kg/min) was begun at T = 60 min s, and continued for the duration of the experiment. Measurements and Main Results: Both experimental regimens produced shock, with decrease d mean arterial pressure and systemic vascular resistance, without cha nge in cardiac output and oxygen delivery, Endotoxin plus saline infus ion decreased gastrointestinal mucosal blood flow to <60% of baseline and decreased gastrointestinal pH. In contrast, gastrointestinal mucos al blood flow returned to baseline values, and intramucosal pH tended to normalize by the end of the saline solution plus dobutamine resusci tative protocol. Conclusion: Compared with saline solution alone, sali ne solu- tion plus dobutamine increased blood flow to the gastrointest inal mucosa, and may have partially improved oxygenation.