MICROVASCULAR VASOCONSTRICTION AND MUCOSAL HYPOPERFUSION OF THE RAT SMALL-INTESTINE DURING BACTEREMIA

Our previous studies have demonstrated that bacteremia induces vasocon striction and hypoperfusion of the small intestinal microcirculation. The present study used time-transit doppler flowmetry, intravital micr oscopy, and laser doppler fluximetry to measure superior mesenteric ar tery (SMA) blood flow, intestinal microvascular blood flow, and mucosa l perfusion. The aim of this study was to determine the relative impor tance of the intestinal macro- and microcirculations in the developmen t of mucosal hypoperfusion. Animals were infused with 5 x 10(8) colony -forming units of Escherichia coli/100 g body weight or saline as cont rol. Bacteremia induced a normotensive, normodynamic state. SMA blood flow was unaffected by bacteremia, but arteriolar vasoconstriction (ap proximately -30%) and microvascular hypoperfusion (approximately -70%) occurred. Mucosal perfusion decreased by 40% from baseline, and was t emporally correlated with microvascular hypoperfusion. From these data , we conclude that the microcirculation has a central role in the deve lopment of mucosal hypoperfusion during bacteremia.