Impact of incorporating the evaluation of full inflation recommended in the 2019 spirometry standards on the evaluation of spirometry acceptability

Abstract

Background: The 2019 ATS/ERS spirometry standards recommend a test to verify forced exhalations start from full inflation. At the end of forced exhalation the patient is coached to rapidly inhale to full inflation again to generate a forced inspiratory vital capacity (FIVC). Only efforts showing a difference (FIVC - FVC) no more than the larger of 0.100L or 5% of the FVC should be considered acceptable for reporting. We examined the impact of incorporating this evaluation into the quality assessment of spirometry data.

Objective/Question/Hyposthesis: The objective evaluation of full inflation will identify data that should not be included in clinical trial datasets.

Methods: We performed two reviews of 646 measurements using the criteria specified in both the 2005 and 2019 standards, including the evaluation of full inflation. We compared the number of measurements that would be reported as good quality (grade A or B for both FVC and FEV1) using the 2005 and 2019 standards.

Results: 86 measurements (13.3%) were rated Grade A or B for both FVC and FEV1 using the 2005 criteria but showed <=1 forced exhalations starting from a lung volume significantly below full inflation (FIVC - FVC)/FVC) >0.05 and were rated Unacceptable by the 2019 standards. 57 measurements (8.8%) showed an FIVC too small to be useful in evaluating full inflation (FIVC < 90% of FVC).

Measurements and Main Results: Achieving full inflation is critical for accurate data and study outcomes. ATS/ERS 2019 standards identify data abnormalities that are undetectable using ATS/ERS 2005 standards which suggests the potential for improved data accuracy moving forwards.