Lactate concentrations in the rectal lumen in patients in early septic shock M. IBSEN 1 , J. TENHUNEN 2 , J. WIIS 1 , T. WALDAU 3 , A. Ø. LAURITSEN 4 , K. THORNBERG 5 , H. JOENSEN 6 and A. PERNER 1 1 Department of Intensive Care, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark, 2 Critical Care Medicine Research Group, Department of Intensive Care Medicine, Tampere University Hospital, Finland, 3 Department of Anaesthesia and Intensive Care, Herlev Hospital, University of Copenhagen, Copenhagen, Denmark, 4 Department of Anaesthesia and Intensive Care, Glostrup Hospital, University of Copenhagen, Copenhagen, Denmark, 5 Department of Anaesthesia and Intensive Care, Gentofte Hospital, University of Copenhagen, Copenhagen, Denmark and 6 Department of Anaesthesia and Intensive Care, Bispebjerg Hospital, University of Copenhagen, Copenhagen, Denmark. Background: Previously, we observed that rectal luminal lactate was higher in non-survivors compared with survi- vors of severe sepsis or septic shock persisting 424 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 5 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 5 0.15)] between non-survivors and survivors. The rectal–arterial difference of the lactate con- centration was higher in survivors. There were no differ- ences 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). Accepted for publication 18 May 2010 r 2010 The Authors Journal compilation r 2010 The Acta Anaesthesiologica Scandinavica Foundation P ATIENTS with septic shock almost invariably show changes in both the macro- and micro- circulation at some point during their course of illness. 1–3 The inability of splanchnic blood flow to meet metabolic demands has been proposed to be one factor in the development and persistence of multiple organ failure in patients who appear to be adequately resuscitated. 4 Several different techni- ques with inherent advantages and disadvantages have been used to assess splanchnic blood flow and metabolism. 5–7 Concentrations of lactate in the intestinal lumen may be a sensitive marker of hypoperfusion-in- duced intestinal metabolic dysfunction compared with lactate levels in blood, intestinal serosa or mucosa as observed in animal studies of occlusive gut ischaemia. 8–11 Luminal equilibrium dialysis is a simple, minimally invasive method for the esti- mation of extracellular concentration of small molecules in the rectal mucosa. The method has been used to show differences in electrolyte trans- port and production of inflammatory markers in patients with inflammatory bowel disease. 12–14 Using this method in patients with severe sepsis and septic shock persisting for more than 24 h, we have shown previously that luminal con- centrations of lactate in the rectum correlate with large bowel permeability 15 and disease severity and outcome 16 indicating pathophysiological relevance. 827 Acta Anaesthesiol Scand 2010; 54: 827–832 Printed in Singapore. All rights reserved r 2010 The Authors Journal compilation r 2010 The Acta Anaesthesiologica Scandinavica Foundation ACTA ANAESTHESIOLOGICA SCANDINAVICA doi: 10.1111/j.1399-6576.2010.02263.x