Redefining end of test (EOT) criteria for pulmonary function testing in children

Area of Science:

• Pulmonary Medicine
• Pediatric Respiratory Physiology
• Diagnostic Spirometry

Background:

• Current American Thoracic Society (ATS) standards for spirometry end-of-test (EOT) criteria require a minimum expiration time of 6 seconds and minimal volume change.
• These ATS EOT criteria are frequently not met by children during Forced Vital Capacity (FVC) maneuvers.
• However, pediatric spirometry tests often demonstrate good reproducibility with repeated efforts.

Purpose of the Study:

• To develop and validate new EOT criteria for spirometry that are more appropriate for children.
• To align EOT criteria with observed reproducibility in pediatric FVC maneuvers.
• To improve the assessment of lung function in pediatric populations.

Main Methods:

• Utilized exponential curve fitting to model the volume-time tracing of FVC maneuvers.
• Determined a theoretical full FVC (FVCFULL) at the asymptote of the fitted curve.
• Proposed 95% of FVCFULL (FVC95) as a novel EOT criterion for children.

Main Results:

• Only 19% of 382 pediatric patients (ages 5-18) met the current ATS EOT criteria.
• Despite failing ATS EOT criteria, 91% met reproducibility criteria for FEV1 and FVC.
• A significant majority (90%) of patients achieved the proposed FVC95 criterion.

Conclusions:

• The FVC95 criterion is a more suitable EOT standard for pediatric spirometry than current ATS criteria.
• The FVC95 criterion was met by 90% of patients, indicating better applicability in children.
• Coaching for maximal effort and individual exponential curve fitting to determine FVC95 are recommended for pediatric spirometry.