There is animal evidence that inhaled nitric oxide (NO) reduces lung inflammation, improves surfactant function, attenuates hyperoxic lung injury, and promotes lung growth. It is hoped, therefore, that it might prevent bronchopulmonary dysplasia (BPD). Trials in preterm infants with respiratory failure have, however, given inconclusive results. Now two US multicentre trials have provided some support for treatment with inhaled NO.

In a 21-centre trial (

; see also editorial, ibid: 404–6) 582 infants (birthweights 500–1250 g, …