Lactic acidosis in the rectal lumen of patients with septic shock measured by luminal equilibrium dialysis

Abstract

Background. Gut ischaemia may contribute to morbidity in sepsis, but little is known about the metabolic state of the gut mucosa in such patients. Methods. Nine patients with abdominal septic shock treated with norepinephrine, and ten healthy subjects, were subjected to equilibrium dialysis with a rectal balloon. pH, PCO2 and concentrations of L-lactate were measured by auto-analyzer. Results. In rectal dialysis fluid from patients with septic shock, acidosis was present (pH 7.23, 95% CI 7.11-7.36) and concentrations of L-lactate were approximately five times greater than controls (2.5-2.8 vs 0.5-1.2 mmol litre-1). The lactate concentration was related to the dose of norepinephrine (P<0.001). In contrast, values of dialysate PCO2 did not differ significantly between patients and controls (6.4-11.0 vs 8.9-13.8 KPa). Conclusions. The results suggest that, either lactic acidosis in rectal mucosa is related to shock severity, or that norepinephrine causes mucosal ischaemia. In any case, metabolic dysfunction is present in the rectal mucosa in patients with abdominal septic shock treated with norepinephrine.