Inhaled nitric oxide (iNO) improves oxygenation in term infants with respiratory failure.
However, iNO has been primarily used in infants receiving mechanical ventilation. This study
is a pilot study to determine if iNO given into an oxygen hood is effective in improving
oxygenation in term and near-term infants who have poor oxygenation but who are not yet
Inhaled nitric oxide (iNO) is currently used in the management of ventilated neonates with
hypoxemic respiratory failure. We have shown that iNO administered by oxygen hood reduces
pulmonary vascular resistance in hypoxia- and group B streptococcus-induced pulmonary
hypertension in an animal model (J Perinatol 2002; 22:50-6). Our objective was to determine
the feasibility of iNO administration by oxygen hood in neonates with respiratory failure.
Methods: A masked randomized controlled trial was performed on eight infants with
respiratory failure. Inclusion criteria were: gestation>34 weeks, age<7 days, with
post-ductal arterial line, and A-aDO2 400-600 on two consecutive blood gases. Infants were
randomized to study gas (iNO at 20 ppm or equivalent flow of O2) for 1 hr which was then
weaned over the next 4 hours. The iNO was introduced into an oxygen hood using an INOvent
(INO Therapeutics, Inc). The primary outcome was the PaO2 one hour after randomization.
Environmental leakage of NO and NO2 were measured. Results: Four infants were randomized to
iNO and four to O2 (controls). Two of the four infants given iNO had an increase in PaO2 of
>100 mm Hg, while oxygenation was unchanged in the controls. Methemoglobinemia and other
adverse effects were not noted in any infant. Environmental levels of NO and NO2 were
minimal (<1ppm) to undetectable at >0.3m from the hood. Conclusions: Administration of iNO
by oxygen hood is feasible. Larger randomized controlled trials are required to measure the
efficacy and determine an appropriate target population for this technique.
- gestation >34 weeks at birth
- age <7 days
- post-ductal arterial line
- an A-aDO2 of 400 to 600 on two blood gases, at least 30 minutes apart.
- Infants with major malformations
- Infants with cardiac disease