The effects of vasopressors with and without dobutamine on haemodynamics, metabolism and gut injury during endotoxic shock in rabbits. A controlled study

Introduction
Vasopressors increase arterial pressure but they may have deleterious effects on mesenteric blood flow. We aimed to evaluate the response of gut biomarkers and superior mesenteric blood flow to different vasopressors with and without dobutamine.

Material and methods
Thirty New Zealand rabbits were included and randomly allocated to 5 groups: group A – sham group; group B – norepinephrine; group C – norepinephrine plus dobutamine; group D – vasopressin; and group E – vasopressin plus dobutamine. Mean arterial pressure (MAP) target was greater than 60 mmHg. Endotoxic shock was induced by intra­venous injection of lipopolysaccharide (LPS) in four of the five groups. Aortic blood flow (Qao), superior mesenteric artery flow (QSMA) and lactate were measured after LPS injection. Enterocyte damage was evaluated by measurements of serum citrulline and intestinal fatty acid-binding protein (I-FABP) after 4 h.

Results
The largest reduction in Qao occurred in group D (64 ± 17.3 to 38 ± 7.5 mL min–1; P = 0.04). QSMA also declined significantly in groups D and E and remained lower than in the other groups over 4 h (group D – baseline: 65 ± 31; 1 h: 37 ± 10; 2 h: 38 ± 10; 3 h: 46 ± 26; and 4 h: 48 ± 15 mL min–1; P < 0.005; group E – baseline: 73 ± 14; 1 h: 28 ± 4.0; 2 h: 37 ± 6.4; 3 h: 40 ± 11; and 4 h: 48 ± 11; P < 0.005; all in mL min–1). Serum citrulline was significantly lower in groups D (P = 0.014) and E (P = 0.019) in comparison to group A. The fluid administration regimen was similar in all groups.

Conclusions
Vasopressin seems to negatively impact gut enterocyte function during endotoxic shock despite the association of an inodilator and adequate fluid replacement.