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Lung function in awake healthy infants: the first five days of life
K C Lødrup-Carlsen1, K H Carlsen
1Dept. of Paediatrics, Ullevål Hospital, Oslo, Norway.
Insights
Optimal infant lung function measurements for research are between days 2-4 of life. These respiratory measurements are not affected by delivery method, ensuring reliable epidemiological data.
Area of Science:
- Neonatal physiology
- Respiratory medicine
- Pediatric pulmonology
Background:
- Establishing normative lung function data in neonates is crucial for early detection of respiratory abnormalities.
- Environmental factors and delivery mode may influence early respiratory development and lung function parameters.
Purpose of the Study:
- To determine the optimal timing for measuring lung function in healthy, awake infants before significant environmental exposure.
- To assess the variability and reproducibility of lung function measurements over the first five days of life.
- To investigate potential differences in lung function based on delivery mode (vaginal vs. Cesarean section).
Main Methods:
- Measurement of tidal flow-volume loops, respiratory system compliance (Crs), and resistance (Rrs) using the single breath passive occlusion technique.
- Serial lung function assessments were conducted in 24 healthy infants at one hour and on the subsequent four days of life.
- Comparison of lung function parameters between vaginally-delivered and Cesarean-delivered infants.
Main Results:
- Tidal volumes increased significantly from Day 0 to Day 1.
- Expiratory flow-time and flow-volume ratios were lower on Day 1 compared to Day 0 but stabilized thereafter.
- Respiratory system compliance (Crs) and resistance (Rrs) were lower on Day 0 and showed higher intra-individual variation in the first two days.
- No significant differences in lung function were observed between infants delivered vaginally or via Cesarean section.
Conclusions:
- Tidal lung function parameters in healthy infants are suitable for epidemiological studies from Day 2 to Day 4 of life.
- Lung function measurements in this period are not influenced by the mode of infant delivery.
- These findings provide a reliable window for non-invasive neonatal respiratory assessment.
Abstract:
Our main aim was to determine an appropriate time for lung function measurements in infants, prior to environmental influences upon their respiratory tract. Tidal flow-volume loops, respiratory system compliance (Crs) and resistance (Rrs) (single breath passive occlusion technique) were measured in 24 healthy, awake awake infants, at one hour and on the following four days of life to investigate variability and reproducibility over time. Possible differences in lung function were sought between the 12 vaginally-delivered and 12 Caesarean section-delivered infants. Tidal volumes increased each day, but significantly so only from Day 0 to Day 1. The expiratory flow-time ratios (time to reach peak expiratory flow to total expiratory time (Tme/Te) and tidal expiratory flow at 75% to peak flow (TEF25/PTEF)) and expiratory flow-volume ratio (volume to reach peak expiratory flow to total expiratory volume (Vme/Ve)) were significantly smaller on Day 1 than Day 0, but did not change significantly thereafter. Crs and Rrs were lower on Day 0 than later. Intra-individual variation remained stable for tidal flow-volume parameters throughout the study, but was significantly higher during Day 0 and Day 1 for Crs and Rrs. There were no significant differences related to mode of delivery of the infant. We conclude that, for epidemiological purposes, tidal lung function parameters may be measured from Day 2 to Day 4, and that they are not influenced by mode of delivery of the infant.