Safety of inhaled nitric oxide after lung transplantation

Background: The present study tests the hypothesis that therapy with inhaled nitric oxide (iNO) at the time of lung transplantation in patients undergoing bilateral single lung transplantation: (i) is safe; and (ii) does not increase either the duration of mechanical ventilation or the incidence of acute graft dysfunction. Methods: We conducted a prospective, non-randomized trial of iNO at 20 parts per million. The treatment group was comprised of 14 patients (10 females, 4 males) undergoing lung transplantation to address severe end-stage lung disease and pulmonary hypertension (mean pulmonary artery pressure > 30 mmHg). Clinical and histologic parameters were compared with 22 historical control subjects who were matched with the study population for age, diagnosis and disease severity (17 females, 5 males) and had undergone lung transplantation in the preceding 2-year time period. No significant differences were noted between the 2 study groups at baseline. Results: No toxic effect of iNO treatment was evident. Although the incidence of acute graft dysfunction was the same in both groups, the occurrence of acute graft rejection in the initial 4 weeks after transplant was less frequent in the iNO group than in the control group (7% vs 32%, p = 0.05). Fifty percent of the treatment group, as compared with 22% of the control group, were discharged from the hospital within 2 weeks of the procedure (p = 0.05). Conclusions: Early initiation of iNO in lung transplant patients with pulmonary hypertension is safe and may decrease the incidence of acute graft rejection. We speculate that iNO may exert an immunomodulatory effect.