Nitric oxide therapy for the newborn infant

Echocardiographic Assessment of Pulmonary Arterial Hypertension Following Inhaled Nitric Oxide in Infants with Severe Bronchopulmonary Dysplasia

OBJECTIVES

Inhaled nitric oxide (iNO) is an effective pulmonary vasodilator. However, the efficacy of iNO in former premature infants with established bronchopulmonary dysplasia (BPD) has not been studied. This study aimed to determine the efficacy of iNO in reducing pulmonary artery pressure in infants with severe BPD as measured by echocardiography.

STUDY DESIGN

Prospective, observational study enrolling infants born at less than 32 weeks gestation and in whom (1) iNO therapy was initiated after admission to our institution, or (2) at the outside institution less than 48 h before transfer and received an echocardiogram prior to iNO initiation, and (3) had severe BPD. Data were collected at three time-points: (1) before iNO; (2) 12-48 h after initiation of iNO; and (3) 48-168 h after initiation of iNO. The primary outcome was the effect of iNO on pulmonary artery pressure measured by echocardiography in patients with severe BPD between 48 and 168 h after initiating iNO therapy.

RESULTS

Of 37 enrolled, 81% had echocardiographic evidence of pulmonary arterial hypertension (PAH) before iNO and 56% after 48 h of iNO (p = 0.04). FiO2 requirements were significantly different between time-points (1) and (3) (p = 0.05). There were no significant differences between Tricuspid Annular Plane Systolic Excursion (TAPSE) Z-Scores, time to peak velocity: right ventricular ejection time (TPV:RVET), and ventilator changes.

CONCLUSIONS

Although we found a statistically significant reduction of PAH between time-point (1) and (3), future trials are needed to further guide clinical care.

Inhaled nitric oxide for respiratory failure in preterm infants

BACKGROUND

Inhaled nitric oxide (iNO) is effective in term infants with hypoxic respiratory failure. The pathophysiology of respiratory failure and the potential risks of iNO differ substantially in preterm infants, necessitating specific study in this population.

OBJECTIVES

To determine effects of treatment with inhaled nitric oxide (iNO) on death, bronchopulmonary dysplasia (BPD), intraventricular haemorrhage (IVH) or other serious brain injury and on adverse long-term neurodevelopmental outcomes in preterm newborn infants with hypoxic respiratory failure.Owing to substantial variation in study eligibility criteria, which decreases the utility of an overall analysis, we divided participants post hoc into three groups: (1) infants treated over the first three days of life because of defects in oxygenation, (2) preterm infants with evidence of pulmonary disease treated routinely with iNO and (3) infants treated later (after three days of age) because of elevated risk of BPD.

SEARCH METHODS

We used standard methods of the Cochrane Neonatal Review Group. We searched MEDLINE, Embase, Healthstar and the Cochrane Central Register of Controlled Trials in the Cochrane Library through January 2016. We also searched the abstracts of the Pediatric Academic Societies.

SELECTION CRITERIA

Eligible for inclusion were randomised and quasi-randomised studies in preterm infants with respiratory disease that compared effects of iNO gas versus control, with or without placebo.

DATA COLLECTION AND ANALYSIS

We used standard methods of the Cochrane Neonatal Review Group and applied the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach to assess the quality of evidence.

MAIN RESULTS

We found 17 randomised controlled trials of iNO therapy in preterm infants. We grouped these trials post hoc into three categories on the basis of entry criteria: treatment during the first three days of life for impaired oxygenation, routine use in preterm babies along with respiratory support and later treatment for infants at increased risk for bronchopulmonary dysplasia (BPD). We performed no overall analyses.Eight trials providing early rescue treatment for infants on the basis of oxygenation criteria demonstrated no significant effect of iNO on mortality or BPD (typical risk ratio (RR) 0.94, 95% confidence interval (CI) 0.87 to 1.01; 958 infants). Four studies examining routine use of iNO in infants with pulmonary disease reported no significant reduction in death or BPD (typical RR 0.94, 95% CI 0.87 to 1.02; 1924 infants), although this small effect approached significance. Later treatment with iNO based on risk of BPD (three trials) revealed no significant benefit for this outcome in analyses of summary data (typical RR 0.92, 95% CI 0.85 to 1.01; 1075 infants).Investigators found no clear effect of iNO on the frequency of all grades of IVH nor severe IVH. Early rescue treatment was associated with a non-significant 20% increase in severe IVH.We found no effect on the incidence of neurodevelopmental impairment.

AUTHORS' CONCLUSIONS

iNO does not appear to be effective as rescue therapy for the very ill preterm infant. Early routine use of iNO in preterm infants with respiratory disease does not prevent serious brain injury or improve survival without BPD. Later use of iNO to prevent BPD could be effective, but current 95% confidence intervals include no effect; the effect size is likely small (RR 0.92) and requires further study.

Inhaled nitric oxide for respiratory failure in preterm infants

BACKGROUND

Inhaled nitric oxide (iNO) is effective in term infants with hypoxic respiratory failure. The pathophysiology of respiratory failure and the potential risks of iNO differ substantially in preterm infants, necessitating study in this population.

OBJECTIVES

To determine the effect of treatment with iNO on death, bronchopulmonary dysplasia (BPD), intraventricular hemorrhage (IVH), and neurodevelopmental disability in preterm newborn infants with respiratory disease.

SEARCH STRATEGY

Standard methods of the Cochrane Neonatal Review Group were used. MEDLINE, EMBASE, Healthstar and the Cochrane Central Register of Controlled Trials (The Cochrane Library) were searched covering the years from 1985 to 2010. In addition, the abstracts of the Pediatric Academic Societies were also searched.

SELECTION CRITERIA

Randomized and quasi-randomized studies in preterm infants with respiratory disease that compared the effects of iNO gas to control, with or without placebo were eligible.

DATA COLLECTION AND ANALYSIS

Standard methods of the Cochrane Neonatal Review Group were used.

MAIN RESULTS

Fourteen randomized controlled trials of inhaled nitric oxide therapy in preterm infants were found. The trials have been grouped post hoc into three categories depending on entry criteria; entry in the first three days of life based on oxygenation criteria, routine use in preterm babies with pulmonary disease, and later enrolment based on an increased risk of BPD. No overall analyses were performed.Nine trials of early rescue treatment of infants based on oxygenation criteria demonstrated no significant effect of iNO on mortality or BPD. Three studies with routine use of iNO in infants with pulmonary disease also demonstrated no significant reduction in death or BPD [typical RR 0.93 (95% CI 0.86 to 1.01)] although this small effect approached significance. Later treatment with iNO based on the risk of BPD (two trials) demonstrated no significant benefit for this outcome in analyses which are possible using summary data.There is no clear effect of iNO on the frequency of all grades of IVH or of severe IVH. Early rescue treatment was associated with a non-significant 20% increase in severe IVH.No effect on the incidence of neurodevelopmental impairment was found.

AUTHORS' CONCLUSIONS

iNO as rescue therapy for the very ill preterm infant does not appear to be effective. Early routine use of iNO in preterm infants with respiratory disease does not affect serious brain injury or improve survival without BPD. Later use of iNO to prevent BPD might be effective, but requires further study.

Inhaled nitric oxide for respiratory failure in preterm infants

BACKGROUND

Inhaled nitric oxide (iNO) has been proven to be effective in term infants with hypoxic respiratory failure. The pathophysiology of respiratory failure, and the potential risks, differ substantially in preterm infants. Therefore, analysis of the efficacy and toxicities of iNO in infants born before 35 weeks is necessary.

OBJECTIVES

To determine the effect of treatment with iNO on the rates of death, bronchopulmonary dysplasia (BPD), intraventricular haemorrhage (IVH), or neurodevelopmental disability in preterm newborn infants (< 35 weeks gestation) with respiratory disease.

SEARCH STRATEGY

Standard methods of the Cochrane Neonatal Review Group were used. MEDLINE, EMBASE, Healthstar and the Cochrane Central Register of Controlled Trials (CENTRAL, The Cochrane Library) were searched, using the following keywords: nitric oxide, clinical trial, and newborn covering the years from 1985 to 2006. In addition, the abstracts of the Pediatric Academic Societies were also searched.

SELECTION CRITERIA

Randomised and quasi-randomised studies in preterm infants with respiratory disease that compared the effects of administration of iNO gas compared to control, with or without placebo are included in this review.

DATA COLLECTION AND ANALYSIS

Data regarding clinical outcomes including death, BPD (defined as oxygen dependence at 36 weeks postmenstrual age), IVH, periventricular leukomalacia (PVL), long term neurodevelopmental outcome and short term effects on oxygenation were excerpted from the trial reports by the investigators. Standard methods of the Cochrane Neonatal Review Group were used. Two investigators extracted, assessed and coded separately all data for each study. Any disagreement was resolved by discussion.

MAIN RESULTS

Eleven randomised controlled trials of inhaled nitric oxide therapy in preterm infants were found. The trials have been grouped post hoc into three categories depending on the entry criteria; entry in the first three days of life based on oxygenation criteria (Kinsella 1999; Hascoet 2004; INNOVO 2005; Van Meurs 2004; Mercier 1999; Dani 2006), routine use in intubated preterm babies (Schreiber 2003; Kinsella 2006) and later enrolment based on an increased risk of BPD (Subhedar 1997; Ballard 2006). The usefulness of the overall analyses was considered limited by the differing characteristics of the studies, and only subgroup analyses were performed. Trials of early rescue treatment of infants based on oxygenation criteria demonstrated no significant effect of iNO on mortality or BPD. The subgroup of studies with routine use of iNO in intubated preterm infants demonstrated a marginally significant reduction in the combined outcome of death or BPD [typical RR 0.91 (95% CI 0.84, 0.99); typical RD -0.06 (95% CI -0.12, -0.01)]. Later treatment with iNO based on the risk of BPD demonstrated no significant benefit for this outcome in our analysis. Studies of early rescue treatment with iNO demonstrated a trend toward increased risk of severe IVH, whereas the subgroup of studies with routine use in intubated preterm infants seems to show a reduction in the risk of having either a severe IVH or PVL [typical RR 0.70 (95% CI 0.53, 0.91); typical RD -0.07 (95% CI -0.12, -0.02)]. Later iNO treatment of infants at risk of BPD is given after the major risk period for IVH, and does not appear to lead to progression of old lesions. Two studies (Schreiber 2003; INNOVO 2005) presented data on long term neurodevelopmental outcome. The early routine treatment study (Schreiber 2003) showed an improved outcome at two years corrected age, while the rescue treatment study (INNOVO 2005) showed no effect of iNO.

AUTHORS' CONCLUSIONS

iNO as rescue therapy for the very ill ventilated preterm infant does not appear to be effective and may increase the risk of severe IVH. Later use of iNO to prevent BPD also does not appear to be effective. Early routine use of iNO in mildly sick preterm infants may decrease serious brain injury and may improve survival without BPD. Further studies are needed to confirm these findings, to define groups most likely to benefit, and to describe long term outcomes.

Inhaled nitric oxide in term and near-term infants: neurodevelopmental follow-up of the neonatal inhaled nitric oxide study group (NINOS)

BACKGROUND

Inhaled nitric oxide (INO) improved oxygenation and reduced the occurrence of death or extracorporeal membrane oxygenation in term and near-term hypoxic neonates. We report the results of neurodevelopmental follow-up of infants enrolled in the NINOS trial.

METHODS

Hypoxic infants >/=34 weeks' gestation and <14 days of age were randomized to 20 ppm INO or 100% oxygen as control. Comprehensive neurodevelopmental assessment of survivors occurred at 18 to 24 months of age.

RESULTS

A total of 235 infants were enrolled in the original trial. There were 36 deaths, 20 of 121 infants in the control group and 16 of 114 infants in the INO-treated group. Of the 199 surviving infants, 173 (86.9%) were seen for follow-up (88 members of the control group and 85 members of the INO-treated group), and 135 infants were normal (69 [79.3%] members of the control group and 66 [77.6%] members of the INO-treated group). Twenty-two infants had sensorineural hearing loss (12 members of the control group and 10 members of the INO-treated group). Moderate to severe cerebral palsy occurred in 13 infants (7 infants in the control group and 6 infants in the INO-treated group). Mental developmental index scores (87 +/- 18.7 in the control group vs 85 +/- 21.7 in the INO-treated group) and psychomotor developmental index scores (93.6 +/- 17.5 in the control group vs 85.7 +/- 21.2 in the INO-treated group) were not different. A total of 29.6% of the control group compared with 34.5% of the INO-treated group had at least one disability. Infants with congenital diaphragmatic hernia, enrolled in a separate but parallel trial, had similar outcomes with a higher incidence of sensorineural hearing loss.

CONCLUSION

Inhaled nitric oxide is not associated with an increase in neurodevelopmental, behavioral, or medical abnormalities at 2 years of age.