[Changes in gastric intramucosal pH and hepato-splanchnic oxygen extraction ratio after heart surgery]

The Do2/VO2 balance of splanchnic organs after heart surgery was evaluated using two different methods; the measurement of hepato-splanchnic oxygen extraction ratio (OERspl) and gastric intramucosal pH (pHi) employing a hepatic venous catheter and a gastric tonometric catheter. Systemic oxygen extraction ratio was within normal ranges during the 24 hours of the experiment, but pHi decreased and OERspl increased significantly at 6 hours after admission to the ICU. Both pHi and OERspl returned gradually to normal levels after 24 hours. We conclude that a period of 24 hours is required to restore sufficient blood flow in the visceral organs to meet oxygen demand and that the pHi reflects the splanchnic DO2/VO2 balance as well as OERspl.