Oxygen consumption, pCO2 gradients and regional blood flow distribution in an alternative model of intestinal autotransplantation

Background. Postoperative complications after intestinal transplantation can be attributed to hypothermic storage and reperfusion injury. Our objective was to evaluate, in an alternative model of intestinal autotransplantation, the initial effects of isolated intestinal hypothermic perfusion (at 4 degrees C, IHP) on mucosal and serosal blood flow distribution and correlate these findings with other systemic and regional markers of mesenteric ischemia. In addition, we sought to obtain evidence that intestinal pCO(2) measurement can be a useful method for monitoring graft perfusion and early histological changes after small bowel transplantation. Materials and methods. Eight dogs (23.3 +/- 1.1 kg) were submitted to a in situ IHP for 30 min, followed by a 180-min reperfusion period. Cardiac output, mesenteric vein, and intestinal serosal blood flows (SMVBF and SBF, ultrasonic flowprobe); intestinal mucosal-arterial PCO2 gradient (D(t center dot a)pCO(2), tonometry); and O-2-derived variables were evaluated. Results. IHP induced a reduction in SMVBF (579 +/- 53 to 321 +/- 10 mL/min) and SBF, (44.7 +/- 3.2 to 29.1 +/- 5.3 mL/min), and an increase in D(t center dot a)pCO(2) (2 +/- 2.8 to 20.5 +/- 4.5 mm Hg). No alterations on systemic metabolic or O-2-derived variables were observed. The increase of the D(t center dot a)pCO(2) correlated with the grade of mucosal injury. Conclusion. IHP induces a proportional reduction on blood flow in all layers of the intestine, and none of the systemic markers of splanchnic ischemia predict the intestinal blood flow disturbances during the early phase of intestinal transplantation. In addition, intestinal pCO(2) measurement seems to be a useful way for monitoring graft perfusion and histological changes after hypothermic ischemia and reperfusion. (c) 2006 Elsevier Inc. All rights reserved.