The significance of ductal shunting during extracorporeal membrane oxygenation.

The purpose of this study was to evaluate the significance and direction of shunts at the level of the foramen ovale or ductus arteriosus in full-term newborns with neonatal respiratory failure who were placed on extracorporeal membrane oxygenation (ECMO). A decrease in left ventricular dimension was expected when infants were placed on ECMO but did not occur. A left-to-right shunt was demonstrated at the ductal level in nine of 12 infants early in the course of ECMO before pulmonary resistance decreased. Presumably, the lack of change in the left ventricular dimension when infants were placed on bypass was due to a left-to-right shunt at the ductal level with ductal flow replacing the right heart output, being drawn into the bypass circuit.