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Inadequate peak expiratory flow meter characteristics detected by a computerised explosive decompression device.
M R Miller1, P R Atkins, O F Pedersen
1Department of Medicine, University of Birmingham, Selly Oak Hospital, Birmingham, UK. m.r.miller@bham.ac.uk
Thorax
|May 3, 2003
Summary
New testing methods reveal that some peak expiratory flow (PEF) meters, like TruZone and MultiSpiro, significantly overestimate readings. This dynamic response error could lead to misclassifying asthma severity in patients.
Area of Science:
- Respiratory Medicine
- Medical Device Engineering
- Pulmonary Function Testing
Background:
- Peak expiratory flow (PEF) meter frequency response requirements are higher than previously understood.
- Existing American Thoracic Society (ATS) waveforms may be inadequate for testing PEF meter dynamic response.
Purpose of the Study:
- To evaluate the dynamic response of various PEF meters using improved testing methods.
- To identify potential inaccuracies in PEF meter performance beyond current ATS standards.
Main Methods:
- Dynamic response of mini-Wright, Vitalograph, TruZone, MultiSpiro, and pneumotachograph meters was assessed.
- A computer-controlled decompression device delivered two distinct flow-time profiles simulating population centiles.
- Differences in recorded PEF between profiles indicated meter dynamic response accuracy.
Main Results:
- Vitalograph, mini-Wright, and pneumotachograph meters showed minimal flow differences (≤10.5%).
- TruZone and MultiSpiro meters exhibited significant flow differences (up to 39.2%), indicating marked overshoot.
- All tested meters met existing ATS accuracy requirements with standard ATS waveforms.
Conclusions:
- An improved dynamic response testing method identified significant underdamping in TruZone and MultiSpiro meters.
- These inaccuracies were not detected by standard ATS waveforms.
- The identified errors could lead to patient misclassification in asthma management.