INHALED NITRIC-OXIDE IN THE TREATMENT OF POSTOPERATIVE GRAFT DYSFUNCTION AFTER LUNG TRANSPLANTATION

Pulmonary hypertension and transient graft dysfunction may complicate the postoperative course of patients undergoing lung transplantation. We report the acute effect of inhaled nitric oxide (80 ppm) on hemodyn amics and gas exchange in 6 patients (median age, 14 years; range, 5 t o 21 years) after lung transplantation as well as the effect of extend ed treatment over 40 to 69 hours in 2 patients. In 5 patients with pul monary hypertension nitric oxide lowered mean pulmonary artery pressur e (from 38.4 +/- 1.6 to 29.4 +/- 3.1 mm Hg; p < 0.05), pulmonary vascu lar resistance index (from 9.3 +/- 1.4 to 6.4 +/- 1.3 Um(2); p < 0.05) , and intrapulmonary shunt fraction (from 28.6% +/- 8.3% to 21.0% +/- 5.7%; p < 0.05). There was a 28.4% +/- 7.2% reduction in transpulmonar y pressure gradient with only minor accompanying effects on the system ic circulation. Mean arterial pressure decreased only 2.7% +/- 5% (fro m 76.4 +/- 2.2 to 74 +/- 2.3 mm Hg; p = not significant), and systemic vascular resistance index by 4.2% +/- 9.7% (from 21.7 +/- 3.1 to 20.6 +/- 3.6 Um(2); p = not significant). Cardiac index was unchanged (fro m 3.5 +/- 0.8 to 3.6 +/- 0.7 L.min(-1).m(-2); p = not significant). Ni tric oxide caused a sustained improvement in oxygenation and pulmonary artery pressure during extended therapy at doses of 10 ppm. There wer e no major side effects. However, transient methemoglobinemia (9%) dev eloped in 1 patient after 10 hours of nitric oxide treatment. Nitric o xide may be useful in the treatment of pulmonary hypertension and the impaired gas exchange that occurs after lung transplantation.