A new experimental model of specific liver hypoxia using membrane oxygenator

The present study introduces a new experimental canine model of hepatic arterial deoxygenation using a membrane oxygenator to investigate the influence of hepatic arterial hypoxia on hepatic hemodynamics and energy metabolism. Eighteen mongrel dogs weighing 10 kg each were randomly divided into three groups: group A served as a control (118.0 +/- 9.0 mmHg of hepatic arterial O2 content), group B as a moderately deoxygenated group (40 mmHg of hepatic arterial O2 content), and group C as a severely deoxygenated group (25 mmHg of hepatic arterial O2 content). Deoxygenation was achieved by perfusion of a gas mixture of O2 and N2 through the membrane oxygenator, which was interposed between the femoral artery and the proper hepatic artery, for 60 min. In group C, hypoxia decreased the mean systemic arterial blood pressure and hepatic arterial blood flow. Arterial blood ketone body ratio (AKBR = acetoacetate/3-hydroxybutyrate), which reflects the hepatic mitochondrial redox state, rapidly decreased prior to the significant increase of glutamate oxaloacetate transminase, glutamate pyruvate transminase, and lactate dehydrogenase after the initiation of hypoxia. Hepatic arterial deoxygenation to 25 mmHg for 60 min induced injury to hepatic hemodynamics, resulting in the deterioration of systemic hemodynamics even after the termination of liver hypoxia. This in vivo temporal hepatic arterial hypoxic model without alteration of inflow volume might be useful for investigating the mechanism of hypoxic injury and the critical point of liver hypoxia on hepatic and/or systemic hemodynamics and liver viability.