PULMONARY VASCULAR-RESISTANCE OF CHILDREN TREATED WITH NITROGEN DURING EARLY INFANCY

Background. We have empirically used supplemental nitrogen in newborns with a functional single ventricle and ductal-dependent systemic perf usion to prevent pulmonary vasodilation and deliver a greater proporti on of flow to the systemic circulation. Thus, we reviewed patient outc ome to determine whether adverse pulmonary vascular effects may be ass ociated with this therapy. Methods. From December 1991 to December 199 5, the fraction of inspired oxygen was adjusted, with supplemental nit rogen if necessary, to maintain an oxygen saturation near 75% in 20 ne wborns awaiting heart transplantation. Medical records were reviewed t o evaluate (1) the duration of nitrogen therapy, (2) pulmonary vascula r histology, (3) postoperative pulmonary hemodynamics, and (4) surviva l. Results. Thirteen patients underwent heart transplantation, 4 patie nts died without surgical intervention, and 3 patients underwent late aortic reconstruction. Supplemental nitrogen was used without exceedin g a fraction of inspired oxygen of 0.21 for 38 +/- 6 days. One patient had evidence of changes of potentially irreversible pulmonary vascula r disease. Pulmonary vascular resistance was not increased long-term i n surviving patients. Conclusions, Supplemental nitrogen can be used t o maintain a systemic oxygen saturation near 75% for an extended perio d in newborns with ductal-dependent systemic perfusion with no long-te rm adverse effect on pulmonary vascular resistance. (C) 1998 by The So ciety of Thoracic Surgeons.