Influence of extra corporeal circulation on myocardial oxygen tension: Results of an animal model

Abstract

Background: Experimental data have shown the potential risk of cellular damage of the myocardium during extra corporeal circulation (ECC). The influence of ECC on myocardial oxygen tension however remained unclear. Therefore, the influence of ECC on the oxygen tension in a beating heart was investigated. Methods: In a pig animal model flexible pO₂ microcatheters were positioned in the midmyocardium of the left ventricle and the skeletal muscle and tissue oxygen tension during ECC were monitored and compared with data of a control group without ECC. Results: ECC and unload of the heart caused a significantly higher increase of myocardial pO₂ than in a non-ECC control group. Conclusion: Our findings show the beneficial effect of ECC on myocardial pO₂. This may support the use of ECC in coronary artery bypass grafting because the potential myocardial injury due to ECC is not related to myocardial ischemia. On the contrary, myocardial pO₂ was even increased during extracorporeal circulation in this study.