[Energy metabolism of the brain, detected with 31-P magnetic resonance spectroscopy during extracorporeal circulation in the rabbit].

The question of a possible brain damage during open heart surgery using extracorporeal circulation is still a problem, especially in infants with circulatory arrest under deep hypothermia. During the last years Magnetic Resonance Spectroscopy was developed, and with this method we have now a possibility to study brain energy metabolism non-invasively and continuously. Our aim was to develop an animal model (rabbit) for studying brain energy metabolism by 31-P Magnetic Resonance Spectroscopy during extracorporeal circulation. In a first step we have shown that the influence of hypothermia on energy metabolism in the brain can be measured in the intact animal by MR-Spectroscopy. In a second step a non-magnetic heart-lung machine for rabbits was constructed and is described here. We get a completely normal brain spectrum in the beginning and after two hours of extracorporeal circulation. The spectrum is also normal on extracorporeal circulation at 35 degrees C and during cooling down to 18 degrees C. With this animal model it will be possible to study different variables of extracorporeal circulation such as duration of circulatory arrest under deep hypothermia or changes of the priming including pharmacological changes.