Fig. 8.

Effect of dopamine infusion on mean systemic arterial and mean pulmonary arterial pressure in normal newborn lambs and lambs with PPHN induced by antenatal ductal ligation. In newborn lambs with normal pulmonary vasculature, systemic blood pressure is significantly higher than pulmonary arterial pressure and increases relatively selectively in response to low doses of dopamine. In PPHN, systemic and pulmonary blood pressures are similar and increase in parallel in response to dopamine.