SPLANCHNIC VASOCONSTRICTION AND BACTERIAL TRANSLOCATION AFTER THERMAL-INJURY

Gut barrier failure and bacterial translocation (BT) after thermal injury may result from splanchnic vasoconstriction and intestinal ischemia. The role of the renin-angiotensin system in intestinal blood flow and BT after thermal injury was studied by pretreatment with the angiotensin-converting enzyme (ACE) inhibitor enalapril in Wistar rats before sham or 30% scald burn. Adequacy of ACE inhibition was documented by the absence of a hypertensive response to angiotensin I, and intestinal blood flow was determined using Cr-51-labeled microspheres. Small bowel blood flow was decreased by 46% at 4-h postburn (P < 0.05) in untreated burned animals despite maintenance of normal cardiac index but returned to baseline levels by 24 h after injury. Enalapril pretreatment resulted in maintenance of small bowel blood flow after thermal injury and was associated with a significantly reduced incidence of BT (20% vs. 75% in untreated burned animals, P < 0.01). These findings further implicate intestinal ischemia in the etiology of gut barrier dysfunction after thermal injury, mediated in part by activation of the renin-angiotensin system.