Modification of cardiopulmonary hemodynamics and vasoactive mediators by extracorporeal membrane oxygenation in newborn lambs

We asked if prolonged venoarterial extracorporeal membrane oxygenation (ECMO) causes alterations in cardiopulmonary hemodynamics that might be reflected in arbiters of vascular tone: thromboxane, prostacylin, norepinephrine, and epinephrine. Newborn lambs undergoing ECMO demonstrated significant augmentation of systemic and pulmonary arterial blood pressure that was temporally related to rises in all vasoactive mediators measured. Although the prostanoids returned to baseline within 30 minutes, the catecholamines remained elevated significantly throughout bypass. Long-term bypass, however, was not associated with sustained systemic hypertension. Pulmonary hypertension was achieved only after 6 hours of bypass. These acute and chronic changes may exacerbate a pathophysiological state for which ECMO is indicated.