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 perfusion to prevent pulmonary vasodilation and deliver a greater proportion of flow to the systemic circulation. Thus, we reviewed patient outcome to determine whether adverse pulmonary vascular effects may be associated with this therapy.


METHODS
From December 1991 to December 1995, the fraction of inspired oxygen was adjusted, with supplemental nitrogen if necessary, to maintain an oxygen saturation near 75% in 20 newborns awaiting heart transplantation. Medical records were reviewed to evaluate (1) the duration of nitrogen therapy, (2) pulmonary vascular histology, (3) postoperative pulmonary hemodynamics, and (4) survival.


RESULTS
Thirteen patients underwent heart transplantation, 4 patients died without surgical intervention, and 3 patients underwent late aortic reconstruction. Supplemental nitrogen was used without exceeding a fraction of inspired oxygen of 0.21 for 38 +/- 6 days. One patient had evidence of changes of potentially irreversible pulmonary vascular disease. Pulmonary vascular resistance was not increased long-term in surviving patients.


CONCLUSIONS
Supplemental nitrogen can be used to maintain a systemic oxygen saturation near 75% for an extended period in newborns with ductal-dependent systemic perfusion with no long-term adverse effect on pulmonary vascular resistance.
Day
R W
RW
Division of Pediatric Cardiology, Primary Children's Medical Center, University of Utah, Salt Lake City 84113, USA. ron.day@hsc.utah.edu
Barton
A J
AJ
Pysher
T J
TJ
Shaddy
R E
RE
D000280:Administration, Inhalation; D001011:Aorta / Q000601:surgery; D001775:Blood Circulation / Q000187:drug effects; D001808:Blood Vessels / Q000473:pathology; D004374:Ductus Arteriosus, Patent / Q000188:drug therapy / Q000503:physiopathology / Q000601:surgery; D016027:Heart Transplantation; D006439:Hemodynamics; D006801:Humans; D018636:Hypoplastic Left Heart Syndrome / Q000188:drug therapy / Q000503:physiopathology / Q000601:surgery; D007231:Infant, Newborn; D008168:Lung / Q000098:blood supply*; D009584:Nitrogen / Q000008:administration & dosage / Q000627:therapeutic use*; D010100:Oxygen / Q000097:blood; D010102:Oxygen Inhalation Therapy; D011652:Pulmonary Circulation / Q000187:drug effects; D012189:Retrospective Studies; D015996:Survival Rate; D013997:Time Factors; D016896:Treatment Outcome; D014655:Vascular Resistance / Q000187:drug effects*; D014661:Vasoconstriction
D009584:Nitrogen; D010100:Oxygen