Extracorporeal membrane oxygenation (ECMO) is frequently used for treatment of patients with severe
hypoxemia due to life-threatening
respiratory failure. Due to this
hypoxemia, the myocardium of these patients is insufficiently provided with
oxygen, and consequently their cardiac function commonly deteriorates. But veno-arterial (V-A) ECMO provides oxygenated blood to the coronary arteries from ECMO circuit insufficiently. To increase the coronary blood flow distributed from ECMO, we placed the arterial
cannula 1 cm above the aortic valve and evaluated the regional blood from the proximal arterial
cannula in comparison with the distal
cannula. Eight neonatal dogs weighting 1.8-2.5 kg were supported by V-A ECMO. The regional blood flow from the arterial
cannula was measured by injection of colored
microspheres into ECMO circuit. The site of the arterial
cannula was changed under fluoroscopy. The bypass flow was maintained at either 50 or 100 ml/min/kg. We found that the coronary blood flow distributed from the proximal arterial
cannula was significantly higher than that from the distal
cannula. The proximal arterial
cannula appears necessary to provide sufficient oxygenated blood to the coronary circulation during V-A ECMO. Therefore, it is expected that the increased cardiac function may improved, and that the survival rate of the patients with retarded cardiac function due to severe
hypoxemia may increase by proximal placement of the arterial
cannula during V-A ECMO.