Abstract 1379

We investigated the effectiveness of Dopamine (DOP) to improve cardiovascular function in an animal model of cardiac depression following ischemia-reperfusion injury of the intestinal tract. A laparotomy was performed in six anesthetized and mechanically ventilated (FiO2: .4) neonatal piglets (10 ± 1 day old). Catheters were inserted in the pulmonary and femoral artery as well as in the cranial sagittal sinus for measurements of cardiac output, vascular pressures and oxygen content. A 3rd generation branch of the superior mesenteric artery was isolated and transiently occluded for 30′. Thereafter volume expansion with 20ml/kg of normal saline was given over 30′. Thirty minutes later the animals were allocated to treatment with DOP at 5,10, 20 and 40 µcg/kg/min, for 20′ periods. The various DOP concentrations were given in a random order. Immediately prior to DOP treatment, cardiac output had decreased in all animals from a mean of 366± 23 to 245 ± 24 ml/kg/min (p<0.001). Mean systemic blood pressure remained unchanged (73 ± 5 vs 71± 3 mmHg) and systemic vascular resistance rose by 50± 12 %. Total oxygen extraction ratio increased from .58 ± .04 to .68 ± .0 3 while oxygen cerebral extraction ratio rose from .60 ± .04 to .77 ± .02 (p<0.05). PaO2 and PaO2 145±14 and 40± 1 mmHg) remained unchanged during the entire experiment. Results of DOP treatments are presented in the table below. Values are in percent changes from levels observed during the immediate pre DOP treatment period. Conclusion : DOP effectively increased cardiac output but failed to change cerebral oxygen extraction. Decrease cerebral blood flow associated to a reduced cardiac output may not be restored by DOP treatment in spite of its efficacy to improve the overall hemodynamic status.

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