Chest
Volume 142, Issue 3, September 2012, Pages 725-733
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Original Research
Pediatrics
Encouraging Pulmonary Outcome for Surviving, Neurologically Intact, Extremely Premature Infants in the Postsurfactant Era

https://doi.org/10.1378/chest.11-1562Get rights and content

Objective

The aim of this study was to determine the long-term pulmonary outcome of extreme prematurity at a single tertiary-care center from 1997 to 2001 in the postsurfactant era.

Methods

We assessed symptoms, exhaled nitric oxide, spirometry, methacholine challenge (provocative concentration of methacholine required to decrease FEV1 by 20% [PC20]), lung volumes, diffusion, and cardiopulmonary exercise tolerance.

Results

Of 279 infants born, 192 survived to discharge, and 79 of these developed bronchopulmonary dysplasia (BPD) (65 mild, 12 moderate, two severe). We studied a subgroup of 53 neurologically intact preterm subjects aged 10 ± 1.5 years (28 with BPD [born, 26.2 ± 1.4 weeks; birth weight, 821 ± 164 g] and 25 without BPD [born, 27.2 ± 1 weeks; birth weight, 1,050 ± 181 g]) and compared them with 23 term control subjects. Of the BPD cases, 21 were mild, seven were moderate, and none was severe; 77.4% of subjects received antenatal steroids, and 83% received postnatal surfactant. Sixty percent of the preterm subjects wheezed at age < 2 years compared with 13% of the control subjects (P < .001), but only 13% wheezed in the past year compared with 0% of control subjects (not significant). For preterm and control subjects, respectively (mean ± SD), FEV1 % predicted was 85% ± 10% and 94% ± 10% (P < .001), with limited reversibility; residual volume/total lung capacity was 29.3% ± 5.5% and 25% ± 8% (P < .05); diffusing capacity/alveolar volume was 89.6% ± 9.2% and 97% ± 10% (P < .005); and PC20 was 6.5 ± 5.8 mg/mL and 11.7 ± 5.5 mg/mL (P < .001). PC20 was < 4 mg/mL in 49% of preterm subjects despite normal exhaled nitric oxide. Most measurements were similar in premature subjects with and without BPD. Peak oxygen consumption and breathing reserve were normal, but % predicted maximal load (measured in Watts) was 69% ± 15% for subjects with BPD compared with 88% ± 23% for subjects without and 86% ± 20% for control subjects (P < .01).

Conclusions

Pulmonary outcome was encouraging at mid-childhood for neurologically intact survivors in the postsurfactant era. Despite mechanical ventilation and oxygen therapy, most had no or mild BPD. Changes found probably reflect the hypoplastic lungs of prematurity.

Section snippets

Subjects

Children born between 1997 and 2001 at a gestational age of ≤ 28 weeks at Schneider Children's Medical Center of Israel (SCMCI) and surviving to mid-childhood were divided into two groups: (1) those with BPD and (2) those without BPD (non-BPD). Although the definition of BPD can be argued, we used the National Institutes of Health consensus definition and severity grading (lung disease requiring oxygen supplementation at 28 days, severity graded by oxygen requirement at a corrected gestational

Results

The attrition of the index study group is described in Figure 1. Of note, of the 87 infants who died before discharge, 70 had severe respiratory disease that often was related to extreme prematurity and contributed at least in part to their deaths. Twenty-eight of 54 survivors of BPD fulfilling inclusion criteria (including all seven with moderate BPD) and 25 of 106 survivors without BPD were recruited, and 23 healthy children comprised the control group. The 53 recruited subjects were of

Discussion

In extremely premature infants, immature lungs are still among the limiting factors for survival and a major cause of neonatal morbidity. This study explores respiratory outcome at mid-childhood in the postsurfactant era, comparing 28 BPD survivors born at a mean gestational age of 26 weeks to 25 non-BPD survivors and 23 term healthy control children.

In this SCMCI cohort, only 192 of 279 infants survived to discharge, and many died of respiratory complications, including severe BPD, as found by

Acknowledgments

Author contributions: Dr Blau had full access to all of the data in the study and takes responsibility for the integrity of the data and the accuracy of the data analysis.

Dr Kaplan: contributed to the study conception and design, patient recruitment, performance of lung function tests, analysis and interpretation of data, and writing of the manuscript.

Dr Bar-Yishay: contributed to the performance of lung function tests, analysis and interpretation of data, and revision of the manuscript.

Dr

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    Funding/Support: This study was supported by a grant from the Israel Association for Clinical Pediatrics.

    Reproduction of this article is prohibited without written permission from the American College of Chest Physicians. See online for more details.

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