inhaled nitric oxide in preterm infants: an updated meta?analysis

background: respiratory distress syndrome and persistent pulmonary hypertension of the newborn are common acquired diseases in preterm infants. in the past several years, randomized controlled trials (rcts) have indicated that inhaled nitric oxide (ino) can potentially lower for both the incidence of bronchopulmonary dysplasia (bpd) and mortality in affected infants. other research has, however, disagreed with these findings. materials and methods: we performed an updated meta?analysis of all relevant rcts to assess the benefits of ino in preterm infants. we searched pubmed, embase, cochrane databases, wanfang, vip, and cnki databases for english and chinese references. results: ultimately, 22 rcts were incorporated. a total of 4901 preterm infants, including the experimental group ( n = 2418) and the control group ( n = 2483), were eligible for inclusion into this meta?analysis. (1) risk of bpd was significantly lower in preterm infants supplemented with ino (relative risk [rr] =0.88; p = 0.0007). there are no differences concerning pulmonary hemorrhage (ph) (rr = 0.94; p = 0.72). (2) incidences of necrotizing enterocolitis (nec), retinopathy of prematurity (rop), and severe intracranial hemorrhage (ich) were compared. no significant difference was discovered concerning these risks (rr = 1.21, p = 0.08; rr = 1.01, p = 0.89; and rr = 0.99, p = 0.86). (3) in addition, no significant differences were found between experimental and control groups with respect to morality. (rr = 1.00, p = 0.98). conclusion: our meta?analysis has shown a beneficial effect in bpd and morality.in addition, our meta?analysis suggests that ino therapy does not increase the risk of common complications, such as nec and rop, and that it may also have no adverse effect on bleeding tendency diseases (severe ich and ph).