OXYGEN TRANSPORT-DEPENDENT SPLANCHNIC METABOLISM IN THE SEPSIS SYNDROME

Objective: Total body oxygen consumption (VO2) may be pathologically o xygen delivery (DO2)-dependent in critically ill patients exhibiting t he sepsis syndrome. This observation has been used to infer the presen ce of occult tissue or organ ischemia that potentially can be eradicat ed by augmenting DO2. We examined this hypothesis by determining the V O2-DO2 relationship and lactate metabolism in the splanchnic region. D esign: Before and after intervention trial. Setting: University-affili ated Veterans Affairs Medical Center, Alien Park, Mich. Patients: Eigh teen surgical patients exhibiting the sepsis syndrome. Intervention: S ystemic and splanchnic oxygen exchange and lactate uptake measurements before and after augmentation of DO2 with blood transfusion. Main Out come Measures: Changes in oxygen exchange and lactate metabolism. Resu lts: The splanchnic VO2 index rose 9% in association with a 26% region al Dot index increase indicating an oxygen transport dependency (P<.05 ). Splanchnic O-2 extraction (0.47 +/- 0.04) was significantly greater than the mean systemic level (0.31 +/- 0.02) and showed a greater dec line following DO2 index augmentation (0.41 +/- 0.04 vs vs 0.28 +/- 0. 03, respectively). However, splanchnic lactate uptake was not changed significantly in response to the increased DO2 index. Conclusions: Alt hough splanchnic oxygen transport dependency and elevated extraction r atios suggest the presence of regional ischemia that should be relieve d with an increased DO2 index, the observed changes in lactate uptake do not support this conclusion. The significance of the VO2-DO2 relati onship, its role in the pathophysiology of the sepsis syndrome, and it s place in the clinical care of the septic surgical patient are in dou bt.