Withdrawal of inhaled nitric oxide from nonresponders after short exposure.
BACKGROUND
Inhaled nitric oxide has been approved by FDA for treatment of hypoxic respiratory failure in term and near-term neonates. The safety of withdrawing NO in patients who fail to respond is a major concern.


OBJECTIVE
To obtain further insight into the safety of withdrawing NO in patients who do not initially respond to this therapy, the charts of patients enrolled at our center in the Neonatal Nitric Oxide Study (NINOS) were reviewed. Oxygenation indices (OI) before, during and after exposure to NO or placebo were compared.


METHODS
The charts of 110 neonates who received NO or placebo within the NINOS trial guidelines from 1995 to 1999 were reviewed. Arterial blood gases of nonresponders before, during and after a 30-minute exposure to different doses of NO or placebo were analyzed.


RESULTS
For both high-dose and 20 ppm nonresponders who received NO, there was no significant change in OI from baseline after withdrawing NO. For patients receiving placebo, there was a significant increase in OI following a 30-minute exposure to placebo.


CONCLUSIONS
NO has been shown to be effective in the treatment of neonatal respiratory failure; however, not all recipients demonstrate clinical improvement. This study showed that withdrawing NO in nonresponders did not cause increased respiratory morbidity when NO exposure was limited to 30 min. Differences between our results and others showing refractory hypoxia after withdrawing NO may be due to different durations of NO exposure and, possibly, its effect on endogenous NO metabolism.
Carriedo
Heather
H
Division of Neonatology, Loma Linda University School of Medicine, 11175 Campus Street, Coleman Pavilion, Loma Linda, CA 92350, USA.
Rhine
William
W
D000280:Administration, Inhalation; D004351:Drug Resistance; D006801:Humans; D007231:Infant, Newborn; D009569:Nitric Oxide / Q000008:administration & dosage*; D010100:Oxygen / Q000097:blood; D012131:Respiratory Insufficiency / Q000188:drug therapy; D013375:Substance Withdrawal Syndrome
D009569:Nitric Oxide; D010100:Oxygen