Intestinal Hemodynamics During Laparotomy

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Abstract
The effects of thoracic epidural anesthesia (TEA) and dopamine infusion (4 μg·kg−1·min−1) on superior mesenteric artery blood flow (SMABF), the mesenteric arteriovenous oxygen difference (AVDo2) and the mesenteric venous lactate concentration were studied in nine patients before abdominal aortic reconstruction. Thoracic epidural anesthesia reduced SMABF, as measured by electromagnetic flowmetry, to 77% ± 8% (mean ± SEM) of control (P < 0.05), and mean arterial pressure to 46% ± 4% of control (P < 0.01). The mesenteric AVDo2 increased from 27 ± 3 to 39 ± 6 mL/L (P < 0.05) and superior mesenteric venous lactate from 1.03 ± 0.11 to 1.60 ± 0.38 mmol/kg (P < 0.05); systemic AVDo2 and lactate did not change. Dopamine had no significant effect on SMABF and mean arterial pressure before TEA. However, dopamine increased SMABF during TEA (from 77% ± 8% to 137% ± 21% of control; P < 0.01), returned mesenteric AVDo2 to 27 ±3 mL/L (P < 0.05), and elevated mean arterial pressure to 62% ± 4% of control (P < 0.05). It is concluded that the decrease in perfusion pressure during TEA reduces SMABF with resultant evidence of intestinal reductive metabolism. The intestinal blood flow during TEA zoos improved by dopamine.