NEW YORK (Reuters Health) – Preterm infants requiring respiratory support do not benefit from inhaled nitric oxide (iNO), according to the results of a meta-analysis of individual patient data from multiple clinical trials.

“Routine use of iNO for treatment of respiratory failure in preterm infants cannot be recommended,” conclude the authors of the study reported in the October issue of Pediatrics.

Dr. Lisa M. Askie, at the University of Sydney, Australia, and colleagues explain that inhaled nitric oxide as a treatment for preventing lung injury in preterm infants has been tested in 14 randomized controlled trials. However, the trials had different designs and the results were divergent – some showed benefit, others showed no effect.

“One way in which to confirm or refute these results and determine if certain patient or treatment characteristics might predict benefit from iNO in premature infants is by undertaking an individual-patient data meta-analysis,” the researchers point out.

For their current study, they were able to obtain data from the original investigators of 11 trials on a total of 3298 infants born at less than 37 weeks gestation requiring mechanical ventilation or continuous positive airway pressure.

Overall, there were no significant differences in outcomes between the infants treated with inhaled NO and controls. Rates of death or chronic lung disease were 59% versus 61% (p=0.11) respectively, and severe neurologic events occurred in 25% and 23% (p=0.09), respectively, the authors found.

Furthermore, these endpoints did not differ significantly by treatment in any subgroup of infants stratified by patient-level characteristics such as gestational age, birthweight, or oxygenation index, according to the report.

Trials that had a higher starting dose of iNO did appear to result in more benefit, but a dose effect was difficult to confirm as most trials varied the dose on the basis of response, Dr. Askie and colleagues note.

“Further study is required to properly assess the effect of iNO exposure (dose and duration) in this population,” they conclude, “and such a study should include appropriately powered trials that specifically test different dosing regimens.”

Reference:
Inhaled Nitric Oxide in Preterm Infants: An Individual-Patient Data Meta-analysis of Randomized Trials
Pediatrics 2011;128:729–739.