Regional blood flow distribution from the proximal arterial cannula duringveno-arterial extracorporeal membrane oxygenation in neonatal dog

Extracorporeal membrane oxygenation (ECMO) is frequently used for treatment of patients with severe hypoxemia due to life-threatening respiratory fail ure. Due to this hypoxemia, the myocardium of these patients is insufficien tly 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 corona ry blood flow distributed from ECMO, we placed the arterial cannula 1 cm ab ove the aortic valve: and evaluated the regional blood flow from the proxim al arterial cannula in comparison with the distal cannula. Eight neonatal d ogs weighting 1.8-2.5 kg were supported by V-A ECMO. The regional blood flo w from the arterial cannula was measured by injection of colored microspher es into ECMO circuit. The site of the arterial cannula was changed under fl uoroscopy. 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 pro ximal arterial cannula appears necessary to provide sufficient oxygenated b lood to the coronary circulation during V-A ECMO. Therefore, it is expected that the increased cardiac function may improved, acid that the survival r ate of the patients with retarded cardiac function due to severe hypoxemia may increase by proximal placement of the arterial cannula during V-A ECMO.