GASTRIC INTRAMUCOSAL PH PREDICTS OUTCOME AFTER SURGERY FOR RUPTURED ABDOMINAL AORTIC-ANEURYSM

Objective: The mortality associated with repair of ruptured abdominal aortic aneurysms (RAAA) remains obstinately high and many deaths resul t from multiple organ failure which is likely to be related to splanch nic ischaemia. The aim of this study is to investigate the importance of splanchnic ischaemia in determining outcome from RAAA by comparing gastric intramucosal pH with other methods of assessing the adequacy o f splanchnic oxygenation. Design and setting: Prospective cohort of pa tients following surgery for RAAA admitted to the Intensive Care Unit of Guy's Hospital, London. Outcome measures: Gastric intramucosal pH ( pHim) and global haemodynamic, oxygen transport and metabolic variable s were measured on admission, at 12 h and at 24 h after admission. Res ults were compared between survivors and non-survivors and Receiver Op erating Characteristic (ROC) curves were constructed to assess the abi lity of each measurement to predict outcome. Results: The median 24 h APACHE II was 18 and the ICU mortality 45.5%. Gastric pHim ?das signif icantly higher in survivors than non-survivors at 24 h (7.42 vs. 7.24, p < 0.01). In survivors who had a low intramucosal pH (pHim) on admis sion there was a significant improvement over the first 24 h (7.26 to 7.40, p < 0.05), whereas in patients who subsequently died, and had a normal pHim on admission, there was a significant fall in pHim (7.35 t o 7.16, p < 0.05). ROC curves showed that gastric pHim was the most se nsitive measurement for predicting outcome in these patients. Conclusi ons: Gastric intramucosal pH is the most reliable indicator of adequac y of tissue oxygenation in patients with RAAA, suggesting that splanch nic ischaemia may have played an important role in determining surviva l.