Effects of inhaled nitric oxide in single lung transplantation in rats with monocrotaline-induced pulmonary hypertension.

BACKGROUND

The edema of grafted lungs during the early postoperative period is one of the serious complications of single lung transplantation for primary pulmonary hypertension.

METHODS

The effectiveness of inhaled nitric oxide in single lung transplantation for primary pulmonary hypertension during the early postoperative period was evaluated with the use of rats with monocrotaline-induced pulmonary hypertension. In the inhaled nitric oxide group, rats were given 60 parts par million of nitric oxide for 24 hours just after left lung transplantation; in the no inhaled nitric oxide group, rats were kept without nitric oxide inhalation; in the control group, normal rats received left isografts.

RESULTS

Three hours after transplantation, the mean pulmonary artery pressure of the no inhaled nitric oxide group (28.0 +/- 4.6) was significantly higher than that of the control group (23.3 +/- 0.9, p < 0.05) and the inhaled nitric oxide group (22.7 +/- 1.7, p < 0.05). On the first postoperative day, the mean left-to-right pulmonary blood flow ratio in the inhaled nitric oxide group was 0.34 +/- 0.03; it showed no significant difference to those of the other two groups, whereas that of the no inhaled nitric oxide group (0.42 +/- 0.14) was significantly elevated compared with that of the control group (0.14 +/- 0.03, p < 0.05). Histopathologically, the edema of the grafted lungs 24 hours after operation in the inhaled nitric oxide group was less severe than that in the no inhaled nitric oxide group.

CONCLUSIONS

The postoperative use of inhaled nitric oxide is effective to reduce the pulmonary edema of the grafts in single lung transplantation for pulmonary hypertension by reducing acute pulmonary blood flow shift toward grafts after transplantation.