Dataset Information

Inhaled nitric oxide effects on lung structure and function in chronically ventilated preterm lambs.

ABSTRACT:

Rationale

Inhaled nitric oxide (iNO) can reverse neonatal pulmonary hypertension and bronchoconstriction and reduce proliferation of cultured arterial and airway smooth muscle cells.

Objectives

To see if continuous iNO from birth might reduce pulmonary vascular and respiratory tract resistance (PVR, RE) and attenuate growth of arterial and airway smooth muscle in preterm lambs with chronic lung disease.

Methods

Eight premature lambs received mechanical ventilation for 3 weeks, four with and four without iNO (5-15 ppm). Four term lambs, mechanically ventilated without iNO for 3 weeks, served as additional control animals.

Measurements

PVR and RE were measured weekly. After 3 weeks, lung tissue was processed for quantitative image analysis of smooth muscle abundance around small arteries (SMart) and terminal bronchioles (SMtb). Radial alveolar counts were done to assess alveolar number. Endothelial NO synthase (eNOS) protein in arteries and airways was measured by immunoblot analysis.

Main results

At study's end, PVR was similar in iNO-treated and untreated preterm lambs; PVR was less in iNO-treated preterm lambs compared with term control animals. RE in iNO-treated lambs was less than 40% of RE measured in preterm control animals. SMart was similar in iNO-treated and both groups of control lambs; SMtb in lambs given iNO was significantly less (approximately 50%) than in preterm control animals. Radial alveolar counts of iNO-treated lambs were more than twice that of preterm control animals. eNOS was similar in arteries and airways of iNO-treated preterm lambs compared with control term lambs.

Conclusions

iNO preserves structure and function of airway smooth muscle and enhances alveolar development in preterm lambs with chronic lung disease.

SUBMITTER: Bland RD

PROVIDER: S-EPMC2718405 | biostudies-literature | 2005 Oct

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Inhaled nitric oxide effects on lung structure and function in chronically ventilated preterm lambs.

Bland Richard D RD Albertine Kurt H KH Carlton David P DP MacRitchie Amy J AJ

American journal of respiratory and critical care medicine 20050623 7

<h4>Rationale</h4>Inhaled nitric oxide (iNO) can reverse neonatal pulmonary hypertension and bronchoconstriction and reduce proliferation of cultured arterial and airway smooth muscle cells.<h4>Objectives</h4>To see if continuous iNO from birth might reduce pulmonary vascular and respiratory tract resistance (PVR, RE) and attenuate growth of arterial and airway smooth muscle in preterm lambs with chronic lung disease.<h4>Methods</h4>Eight premature lambs received mechanical ventilation for 3 wee ...[more]

PMID: 15976381

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Project description:Importance:Bronchopulmonary dysplasia (BPD) occurs in approximately 40% of infants born at younger than 30 weeks' gestation and is associated with adverse pulmonary and neurodevelopmental outcomes. Objective:To test whether administration of inhaled nitric oxide to preterm infants requiring positive pressure respiratory support on postnatal days 5 to 14 improves the rate of survival without BPD. Design, Setting, and Participants:This intent-to-treat study was a randomized clinical trial performed at 33 US and Canadian neonatal intensive care units. Participants included 451 neonates younger than 30 weeks' gestation with birth weight less than 1250 g receiving mechanical ventilation or positive pressure respiratory support on postnatal days 5 to 14. Enrollment spanned from December 23, 2009, to April 23, 2012, and neurodevelopmental outcome studies were completed by April 4, 2014. Interventions:Placebo (nitrogen) or inhaled nitric oxide initiated at 20 ppm was decreased to 10 ppm between 72 and 96 hours after starting treatment and then to 5 ppm on day 10 or 11. Infants remained on the 5-ppm dose until completion of therapy (24 days). Main Outcomes and Measures:The primary outcome was the rate of survival without BPD at 36 weeks' postmenstrual age (PMA). Secondary outcomes included BPD severity, postnatal corticosteroid use, respiratory support, survival, and neurodevelopmental outcomes at 18 to 24 months' PMA. Results:In total, 222 infants (52.3% male [n?=?116]) received placebo, and 229 infants (50.2% male [n?=?115]) received inhaled nitric oxide. Their mean (SD) gestation was 25.6 (1.5) vs 25.6 (1.4) weeks, and their mean (SD) birth weight was 750 (164) vs 724 (160) g. Survival without BPD at 36 weeks' PMA was similar between the placebo and inhaled nitric oxide groups (31.5% [n?=?70] vs 34.9% [n?=?80]) (odds ratio, 1.17; 95% CI, 0.79-1.73). Rates for severe BPD (26.6% [55 of 207] vs 20.5% [43 of 210]) and postnatal corticosteroid use for BPD (41.0% [91 of 222] vs 41.5% [95 of 229]) and the mean (SD) days of positive pressure respiratory support (55 [40] vs 54 [42]), oxygen therapy (88 [41] vs 91 [59]), and hospitalization (105 [37] vs 108 [54]) were equivalent between the 2 groups. No differences in the incidence of common morbidities were observed. Respiratory outcomes on discharge to home, at 1 year, and at age 18 to 24 months' PMA and neurodevelopmental assessments at 18 to 24 months' PMA did not differ between groups. Conclusions and Relevance:Inhaled nitric oxide, initiated at 20 ppm on postnatal days 5 to 14 to high-risk preterm infants and continued for 24 days, appears to be safe but did not improve survival without BPD at 36 weeks' PMA or respiratory and neurodevelopmental outcomes at 18 to 24 months' PMA. Trial Registration:clinicaltrials.gov Identifier: NCT00931632.

Dataset Information

Inhaled nitric oxide effects on lung structure and function in chronically ventilated preterm lambs.

Rationale

Objectives

Methods

Measurements

Main results

Conclusions

Publications

Inhaled nitric oxide effects on lung structure and function in chronically ventilated preterm lambs.

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