Estimation of Expiratory Function in Infants With Passive Expiration From Total Lung Capacity: A Retrospective Study

Area of Science:

• Pediatric Pulmonology
• Respiratory Physiology

Background:

• Evaluating infant expiratory airway function is challenging due to the technical difficulty and high failure rate of the criterion standard, the raised-volume rapid thoracoabdominal compression technique.
• A simpler, reliable method for assessing infant lung function is needed.

Purpose of the Study:

• To determine if passive expiration measurements from total lung capacity correlate with forced expiration measurements obtained by the raised-volume technique in infants.
• To explore the utility of passive flow-volume curves as an alternative method for infant pulmonary function testing.

Main Methods:

• Retrospective analysis of pulmonary function tests in infants (≥ 36 weeks gestation) at Hadassah Medical Centre (2011-2019).
• Inclusion of technically acceptable forced and passive flow-volume curve measurements.
• Comparison of success rates and correlation coefficients between the two techniques.

Main Results:

• Passive flow-volume curves had a higher success rate (70%) compared to forced curves (39%).
• High Spearman correlation coefficients were observed between passive and forced measurements for vital capacity (0.92) and various expiratory flows (0.66-0.83).
• Correlation remained strong across different obstruction levels, sexes, and ages, with low inter-maneuver variability for both methods.

Conclusions:

• Passive flow-volume curves provide reliable and reproducible data in infants.
• These curves demonstrate a high correlation with the forced expiratory technique.
• Passive flow-volume curves represent a viable alternative for evaluating infant expiratory airway function.