Lactate concentrations in the rectal lumen in patients in early septic shock

Background Previously, we observed that rectal luminal lactate was higher in non-survivors compared with survivors of severe sepsis or septic shock persisting > 24 h. The present study was initiated to further investigate this tentative association between rectal luminal lactate and mortality in a larger population of patients in early septic shock. Methods A prospective observational multicentre study of 130 patients with septic shock at six general ICU's of university hospitals. Six to 24 h after the onset of septic shock, the concentration of lactate in the rectal lumen was estimated by a 4-h equilibrium dialysis. Dialysate concentrations of lactate were determined using an auto-analyser. Results The overall 30-day mortality was 32%, with age and Simplified acute physiology scores II and sequential organ failure assessment scores being significantly higher in non-survivors. In contrast, there were no differences in concentrations of lactate in the rectal lumen [2.2 (1.4-4.1) and 2.8 (1.6-5.1) mmol/l (P=0.34)] (medians and 25th-75th percentiles) or arterial blood [2.1 (1.4-4.2) and 2.0 (1.3-3.2) mmol/l (P=0.15)] between non-survivors and survivors. The rectal-arterial difference of the lactate concentration was higher in survivors. There were no differences in blood pressure, noradrenaline dose or central venous oxygen saturation between the groups. Conclusion In this prospective, observational study of unselected patients with early septic shock, there was no difference in the concentration of lactate in the rectal lumen between non-survivors and survivors. Trial Registration Clinicaltrials.gov (no: NCT00197938).