ENDOTOXIN-INDUCED ILEAL VO2-DO2 ALTERATIONS DO NOT CORRELATE WITH THESEVERITY OF ILEAL INJURY

Purpose: Altered VO2-DO2 relationships are most often noted to occur i n the setting of sepsis or endotoxin (LPS)-induced systemic organ micr ovascular injury and are generally thought to be causally linked to th at injury. However, we have recently shown that ileal microvascular in jury is not associated with altered ileal VO2-DO2 relationships. Thus, we hypothesized that the severity of LPS-induced systemic organ micro vascular injury would not correlate with the development of systemic o rgan VO2-DO2 alterations. Materials and Methods: To test this hypothes is, we used the in situ autoperfused feline ileal preparation to simul taneously examine microvascular permeability, reflected as the ileal l ymph to plasma protein concentration ratio (CL/CP), and ileal VO2-DO2 relationships 2 hours after intravenous LPS (0.75-2.0 mg/kg; n = 9) an d in matching controls (n = 5). Results: As expected, all LPS-treated animals were found to have extensive ileal histological damage and mar ked increases in the CL/CP compared with controls (0.308 +/- 0.019 v 0 .097 +/- 0.009; P < .001). In addition, although the critical DO2 (DO( 2)c) was elevated in the LPS-treated animals relative to controls (34. 2 +/- 5.0 v 16.7 +/- 1.4 mL/min/kg: P < .03), there was no correlation between the DO(2)c and the CL/CP in the LPS-treated animals. Finally, ileal wet to dry weight ratios after LPS did not differ from controls . Conclusion: Taken together, these data suggest that factors other th an organ injury, as assessed by morphological and permeability alterat ions, are important in the pathogenesis of altered systemic organ VO2- DO2 relationships after LPS. Copyright (C) 1997 by W.B. Saunders Compa ny.