Analyses of intramucosal pH has provided insight into the pathophysiology of splanchnic ischaemia, although it is unclear whether more accurate information is obtained by determining the pH (with the Henderson-Hasselbalch equation) or simply by measuring the intramucosal pCO2. Although in the clinical setting, tonometry results assist in predicting outcome in selected patients, a positive benefit from tonometry-guided therapy has yet to be demonstrated, and remains a future goal.