The spirometer is an essential tool in the assessment of respiratory health. Spirometry is used to monitor the course of lung health and the effect of disease on the lungs. It measures the response of the airways to specific breathing maneuvers. Spirometry techniques have been standardised globally through the leadership of respiratory health authorities like the American Thoracic Society (ATS) and European Respiratory Society (ERS). Guidelines published by these bodies contain crucial information based on the latest research and is aimed at improving spirometry accuracy and ensuring the safety of patients and healthcare personnel. Compliance to the Standardisation of Spirometry 2019 Update guideline published by the ATS/ERS will reflect the reliability of a spirometer.
In the updated ATS/ERS guideline, several aspects pertaining to spirometers and spirometry techniques were re-defined. The scope of the conditions of use of spirometers is now larger compared to the guideline’s 2005 version. Although the update is centered on clinical spirometers and clinical spirometry, Inofab Health has sought to ensure that the SpiroHome Personal spirometer also complies with the key updates in this guideline as the SpiroHome Personal is designed to provide clinical-grade measurement accuracy in a home environment. The SpiroHome Personal is currently the world's first 2019 ATS/ERS compliant personal spirometer.
Our Inofab Health experts have summarised the key updates of the 2019 guideline and how SpiroHome spirometers comply with each of them:
1. ISO 26782 Compliance
Compliance to the ISO 26782:2009 (Anaesthetic and respiratory equipment — Spirometers intended for the measurement of time forced expired volumes in humans) standard is now compulsory for all spirometers', with the only exception being that the maximum allowable margin of accuracy error ±2.5% still applies.
Validation of spirometer accuracy and compliance to the standard waveforms defined in these standards is achieved with the use of a lung simulator machine, also referred to as a Pulmonary Waveform Generator (PWG). SpiroHome spirometers are validated to repeatedly and reliably out-perform the ±2.5% accuracy limits set by the ATS.
2. The end of forced expiration (EOFE)
Before the 2019 update, a patient was expected to complete a forced expiratory maneuver that lasted at least 6-seconds. The current update states the EOFE is no longer defined by a 6-second minimum forced expiration. One of the following three may signal an EOFE: The new criteria includes reaching expiratory plateau (≤0.025 L in the last 1 s of expiration), when expiratory time ≥15 s or when FVC is within the repeatability tolerance of or is greater than the largest prior observed FVC (when patient cannot/does not reach plateau). In SpiroHome Apps, the end of a maneuver is signalled by a beep sound when any of these are detected.
3. Trial and Session Results
To ensure session accuracy, if the trial is not completed an error message will appear on the app screen. If the trial is completed successfully, a correct trial message will appear on the screen.
The scale and aspect ratio of the Flow/Volume graph displayed in session results has also been updated according to the new requirements. As seen below, the graph aspect ratio changes according to maneuver performance. The graph is scaled according to the maximum values of the session.
Important information such as hesitation time, back extrapolated volume and PEF rise time is also displayed on the session results screen.
4. The Session Grading
For spirometry reporting, an extended grading system is included in the recently published ATS/ERS guideline. A "U" ('usable') grade has been added to the grading system to indicate results that are not technically acceptable but may be clinically useful. FEV1 and FVC parameters are graded separately.
Grading System for FEV1 and FVC (Graded Separately), Retrieved from 2019 ATS Standardisation.
In line with these changes “acceptable” and “usable” grades are displayed for FEV1 and FVC maneuvers on the SpiroHome App results page.
5. Predicted Value Calculation
The standardized ATS default report form should include the GLI reference equations for all ages’ reference values. Predicted values of parameters (except PEF) are calculated from GLI references. PEF value is calculated from Zepletal & ERS1993 formulas.
These five new specifications outlined in the 2019 ATS/ERS guidelines are supported by SpiroHome spirometers and apps, giving SpiroHome users peace of mind that the tools they are using to track their lungs are in line with the standardized requirements and recommendations by the ATS and ERS. Inofab Health is proud to make SpiroHome Personal the first personal spirometer on the market compliant with the latest ATS/ERS guidelines, standing by it’s guarantee that clinical-grade spirometry can be achieved at home by all users.
- Grahaham B.L., Steenbruggen I., Miller M.R., et al. (2019) Standardization of Spirometry 2019 Update. An Official American Thoracic Society and European Respiratory Society Technical Statement. American Journal of Respiratory and Critical Care Medicine. Retrieved from https://www.atsjournals.org/doi/full/10.1164/rccm.201908-1590ST
- Quanjer P.H., Stanojevic S., Cole T.J, Baur X, Hall GL, Culver BH, et al.; ERS Global Lung Function Initiative. Multi-ethnic reference values for spirometry for the 3–95-yr age range: the Global Lung Function 2012 equations. Eur Respir J 2012;40:1324–1343.