We compared the efficacy of iNO and nebulized PGI2, individually or combined, for the treatment of PHT which was produced by a continous infusion of a thromboxane (TX) mimetic (U46,619: 0.06 μg/kg/min). 12 mechanically ventilated piglets (age: 21-30 days, 3.5 ± 0.2 kg). were randomized to receive iNO (40 ppm) or iPGI2 (epoprostenol sodium, FlolanO, Glaxo Wellcome, NC). PGI2 (20 μg/ml) was placed in a jet nebulizer chamber connected to the inspiratory limb of a pressure cycle infant ventilator. Flow rate was 6-8 L/min and Fi02 0.4. The second agent was added 30 minutes later. Blood gases, mean pulmonary artery pressure (mPAP), pulmonary and systemic vascular resistance (PVR, SVR; mm Hg/L/kg/min), cardiac output(QT; ml/kg), dP/dt max (mm Hg/sec) and pulmonary mechanics were measured at the end of each 30 minutes sequence. Results: as mean±S.E.M. *: compared to prior treatment, p<0.01 Table

Table 1 No caption available.
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Initial treatment with either agent similarly decreased PVR (48 ± 4%) and improved oxygenation (22 ± 10% reduction in AaD02). The addition of either second agent further improved PVR and normalized mPAP to pre TX level. No adverse hemodynamic consequences were observed. NO and PGI2 did not significantly affect lung compliance or airway resistance. Combined treatment may be superior to single therapy for pulmonary hypertension.