Arginine-vasopressin attenuates beneficial norepinephrine effect on jejunal mucosal tissue oxygenation during endotoxinaemia

Background The objective of the present study was to investigate the effects of increasing doses of norepinephrine (NE) with or without arginine-vasopressin (AVP) on intestinal oxygen supply and jejunal mucosal tissue oxygen tension in an acute endotoxic pig model. Methods In this prospective, randomized, experimental study on 24 domestic pigs, jejunal mucosal tissue P o 2 ( P o 2 muc) was measured using two Clark-type surface oxygen electrodes. Oxygen saturation of jejunal microvascular haemoglobin (HbO 2 j) was determined by tissue reflectance spectrophotometry. Systemic haemodynamic variables, mesenteric-venous and systemic acid–base and blood gas variables, and lactate measurements were recorded. Measurements were performed at baseline, after Escherichia coli lipopolysaccharide (LPS) administration, and at 20 min intervals during incremental NE infusion (0.05, 0.1, 0.5, 1.0, and 2 µg kg −1 min −1 , respectively) with 57 mU kg −1 h −1 AVP ( n =8; NE+AVP group) or without ( n =8; NE group); or infusion of an equal amount of normal saline ( n =8; CON group). Results LPS infusion led to a significant ( P P o 2 muc and HbO 2 j. Both NE and NE+AVP increased arterial pressure, cardiac output, and mesenteric artery blood flow. Concomitant to an increase in systemic oxygen delivery, NE improved P o 2 muc and HbO 2 j. NE alone was superior in restoration of P o 2 muc when compared with NE+AVP. Conclusions Both NE and NE+AVP improved global haemodynamics and systemic oxygen transport variables when compared with control animals in an acute endotoxic pig model. NE improved jejunal P o 2 muc at all dosages. NE effects were significantly blunted by simultaneous administration of AVP.