Beneficial effects of low-dose prostacyclin on cat intestinal perfusion during endotoxemia as evaluated with microdialysis and oxygen transport variables

Objective: To evaluate the effects of low-dose prostacyclin on intestinal perfusion during endotoxemia. Design: A randomized, blinded experimental study. Setting: A university laboratory. Subjects: Sixteen anesthetized cats. Interventions: The animals received endotoxin by continuous intravenous infusion (0.5 mg/kg plus 0.5 mg kg(-1).hr(-1)) and a continuous volume replacement throughout the experiment. Four hours after the start of endotoxin, the animals were randomized to receive an infusion of either prostacyclin at a dose of 1 ng.kg(-1).min(-1) (prostacyclin group) or vehicle (control group) during the next 4 hrs. Measurements and Main Results: Intestinal vascular resistance was calculated from systemic arterial pressure, central venous pressure, and superior mesenteric artery blood flow, and intestinal oxygen delivery and uptake were calculated from superior mesenteric artery and vein blood samples and blood flow. Interstitial lactate, pyruvate, glucose, and glycerol in the ileal wall were measured by using microdialysis. There were no differences in baseline values between the groups, Systemic blood pressure decreased initially but recovered and remained stable in both groups. In the control group, intestinal vascular resistance increased from 10.9 +/- 1.0 to 24.7 +/- 5.3 mm Hg.mL.min(-1).kg(-1) (p < .05) at 8 hrs, and oxygen delivery decreased from 2.6 +/- 0.2 to 1.3 +/- 0.3 ml min(-1).kg(-1) (p <.05), Simultaneously, microdialysis lactate increased from 1.6 +/- 0.1 to 3.6 +/- 0.5 mmol/L (p <.05) with concomitant pyruvate increase and unchanged lactate/pyruvate ratio. Blood lactate increased and ph decreased. In the prostacyclin group at 8 hrs, intestinal vascular resistance of 6.9 +/- 0.8 mm Hg.mL.min(-1) kg(-1) was lower and intestinal oxygen delivery of 3.2 +/- 0.3 was higher (p <.05) than in the control group at 8 hrs. Intestinal oxygen uptake of 0.54 +/- 0.10 mL.min(-1).kg(-1) was higher than in the control group, in which oxygen uptake was 0.26 +/- 0.04 mL.min(-1) kg(-1). Lactate, pyruvate, and pH were normalized at 8 hrs in the prostacyclin group. Conclusion: Low-dose prostacyclin has beneficial effects on small intestinal perfusion during endotoxemia in this experimental cat model