Reply to Arce: On the 2019 Spirometry Statement

From the Authors:

The comments from Dr. Arce are welcome, as they address the implementation of the 2019 update of the American Thoracic Society (ATS)/European Respiratory Society (ERS) spirometry standards (1). The ATS/ERS spirometry standards describe the basic requirements for conducting spirometry, but it is to be expected that many facilities will have internal requirements and procedures that exceed the basic quality requirements in the spirometry standards.

As the standards state, calibration verification with a calibration syringe must be performed for all spirometers, including spirometers that cannot be recalibrated in the field. The onus for having a calibration syringe available is on the facility conducting spirometry, rather than on the spirometer manufacturer. Manufacturers are not permitted to claim that calibration verification of precalibrated spirometers is not required to meet ATS/ERS Spirometry Standards. For spirometers using disposable flow sensors, one new sensor from the supply used for patient tests must pass a calibration verification each testing day, but the remaining sensors used on that day do not need to be individually verified.

The comment regarding a “reinhalation defect” causing an overestimation of FVC is well taken. The spirometry standards state that the measurement of FVC ends at the beginning of inspiration, but a reinhalation may not be detected if the patient is not wearing nose clips or if an expiration-only spirometer is being used. In these circumstances, the standards should have been more explicit in the need for the operator to be alert for a partial inhalation with continued maximal expiration and indicate that the FVC from such a maneuver is neither acceptable nor usable.

Additional analyses of spirometry data and reporting of additional variables beyond those specified in the standards is an option for those facilities that wish to include them. Many manufacturers offer the ability for a spirometry facility to add such options.

Sharing comments and concerns about the ATS/ERS spirometry standards is important in the evaluation of current standards and the development of new standards. We thank Dr. Arce for this letter.