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The Reference Interval for the Attainment of Comparable Term Functional Levels of Pulmonary Oxygenation Capacity in
Masako Yasui1, Tohru Ogihara1, Shigeo Yamaoka1
1Department of Pediatrics, Division of Neonatology, Osaka Medical and Pharmaceutical University, Takatsuki, Japan.
Insights
Healthy preterm infants achieve stable lung oxygenation near term levels by 42 weeks postmenstrual age (PMA). This study identifies key milestones for discontinuing oxygen and achieving stable SpO2 in premature infants.
Area of Science:
- Neonatology
- Pediatric Pulmonology
- Respiratory Physiology
Background:
- Preterm infants often experience respiratory challenges.
- Establishing stable lung oxygenation is crucial for healthy development.
- Current data on optimal timing for respiratory assessment in preterm infants is limited.
Purpose of the Study:
- To determine the reference interval (RI) for postmenstrual age (PMA) at which lung oxygenation capacity stabilizes in healthy preterm infants.
- To identify the PMA for discontinuing oxygen supplementation (Stop-O2) and achieving stable SpO2 on room air.
- To inform respiratory function assessments and bronchopulmonary dysplasia (BPD) evaluations.
Main Methods:
- Retrospective single-center study of infants born before 34 weeks gestational age (GA).
- Infants discharged without respiratory support and no adverse respiratory outcomes were analyzed.
- Key outcome measures included PMA at Stop-O2 and PMA for stable SpO2 (≥96% on room air for 3 days).
Main Results:
- 176 preterm infants met stable SpO2 criteria.
- The 97.5th percentile for discontinuing oxygen was 40.2 weeks PMA; stable SpO2 was achieved by 41.7 weeks PMA.
- Infants with GA < 30 weeks showed delayed stabilization, with the 97.5th percentile for stable SpO2 at 42.9 weeks PMA.
Conclusions:
- Most healthy preterm infants attain near-term lung oxygenation levels by 42 weeks PMA.
- The findings provide a reference for assessing respiratory function and BPD in preterm infants.
- This data aids in determining optimal timing for respiratory assessments post-preterm birth.
Objective:
We aimed to identify the reference interval (RI) of the postmenstrual age (PMA) at which lung oxygenation capacity is sufficiently stable in healthy preterm infants.
Design And Setting:
A single-center, retrospective study involving a cohort of infants born at gestational age (GA) < 34 weeks who were discharged without respiratory support and experienced no short-term adverse respiratory outcomes.
Outcome Measures:
The PMA when oxygen supplementation was discontinued (Stop-O2), and subsequent SpO2 stabilization at ≥ 96% with room air spontaneous breathing for three consecutive days (Stable-SpO2).
Results:
Of the 243 eligible infants, 176 meeting the Stable-SpO2 criteria before discharge were analyzed. The upper limit of the RI (97.5th percentile) for Stop-O2 was 40.2 weeks PMA and that for Stable-SpO2 was 41.7. Limited to infants with GA < 30 weeks, the 97.5th percentile of Stop-O2 and Stable-SpO2 was 41.9 and 42.9 weeks PMA, respectively. When both indices plotted against GA were divided by K-means clustering, one distinct cluster straddled a wide range of GA with delayed achievement of Stop-O2 (39.6, median weeks PMA) or Stable-SpO2 (40.6). The SpO2 status when Stable-SpO2 criteria was fulfilled (mean SpO2, 97.3%; time spent with SpO2 > 90%, 97.7%) was nearly comparable to that of healthy term infants shortly after birth.
Conclusions:
The lung oxygenation capacity in most healthy preterm infants was near-term levels by 42 weeks PMA. Our data might be useful for determining the optimal timing for assessing respiratory function as well as the presence or absence of bronchopulmonary dysplasia in preterm infants.
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