Potential misinterpretation of infant lung function unless prospective healthy controls are studied

Area of Science:

• Pediatric Pulmonology
• Respiratory Physiology
• Medical Device Evaluation

Background:

• Pulmonary function tests (PFTs) are vital for diagnosing infant lung diseases.
• Existing reference data for infant PFTs are limited, hindering accurate interpretation.
• Commercial equipment advancements necessitate updated reference equations.

Purpose of the Study:

• To evaluate the validity of current published reference equations for infant forced expiratory flow-volume (FEFV) data.
• To assess the impact of using these equations on interpreting PFT results in infants with lung disease.
• To determine the need for updated reference data for infant PFTs.

Main Methods:

• FEFV maneuvers were performed on healthy infants and those with cystic fibrosis (CF) using Jaeger Masterscreen BabyBody equipment.
• Results were initially analyzed using Z-scores based on published reference equations.
• Multilevel modeling was employed to adjust for differences in healthy infants and analyze CF patient data.

Main Results:

• Published equations significantly underestimated FEFV outcomes in healthy infants (e.g., mean Z-score difference of -1.4 for V (maxFRC)).
• Adjustments using multilevel modeling brought mean Z-scores within predicted ranges for healthy infants.
• Using published equations, 41-45% of CF infants' results were deemed "abnormal"; this decreased to 20-28% after adjustment.

Conclusions:

• Reliance on outdated published equations can lead to misinterpretation of infant lung function.
• This misinterpretation can negatively affect research findings and clinical management of infant lung diseases.
• Establishing equipment-specific reference data or using contemporary control groups is essential for accurate infant PFT interpretation.