RESUMO
BACKGROUND: It has been postulated that the derangement of gut perfusion is a factor of the development of multi-organ dysfunction and increasing postoperative morbidity. Gastric mucosal pH (pHim) correlates with splanchnic perfusion and the persistent gastric mucosal acidosis has been supposed to be a predictor of complications after cardiac surgery. The purpose of this study is to measure the change of pHim induced by hypothermic cardiopulmonary bypass (CPB). METHODS: Twelve patients undergoing cardiac surgery were anesthetized with fentanyl and isoflurane. Gastric mucosal PCO2 (PrCO2) and pHim were measured by Tonocap. Temperature was maintained about 28oC during CPB and arterial blood gas tension was managed by alpha-stat mode. Measurement was made at: (1) baseline, after induction of anesthesia, (2) 30 minutes after starting CPB, (3) 60 minutes after starting CPB, (4) at the end of CPB, (5) at the end of operation and (6) at 24 hours after CPB. Statistical analysis was performed using one-way ANOVA and Student t test. RESULTS: The PrCO2 and the CO2 gap (PrCO2 - PaCO2) increased at the end of CPB and maintained the increased state for 24 hours after CPB. The pHim decreased during CPB and maintained the decreased state for 24 hours after CPB. The difference between pHim and pHa increased significantly after CPB. CONCLUSION: We conclude that the hypothermic CPB induces gastric mucosal acidosis and it did not recover for 24 hours after CPB.