1995 OPEN FORUM Abstracts
EVALUATION OF TEN BRANDS OF SINGLE-PATIENT USE PORTABLE PEAK FLOW METERS (PPFMs)
RA Brown, BS, RRT, RPFT; WJ Backes, BS, RRT. Dept of Respiratory Care Services, University of Wisconsin Hospitals and Clinics, Madison, WI, USA.
Introduction: The measurement of Peak Expiratory Flow (PEF) has been touted as a reliable measure of airway caliber, particularly as it relates to beta-agonist response, as well as being an acceptable tool to monitor episodic bronchospasm. The National Asthma Education Program (NAEP) has established minimum performance recommendations for PPFMs. Numerous brands and types of single-patient use PPFMs have been developed since publication of the NAEP recommendations, with PPFM manufacturers stating their monitoring devices comply with these performance recommendations. This study was designed to evaluate 10 brands of recently manufactured single-patient use PPFMs for their ability to measure flows, commonly encountered in clinical practice, in an acceptable and reproducible fashion.
Methods: 10 brands of PPFMs (3 monitors / brand) were studied. PPFMs were positioned approximately 4 inches distally to a calibrated heated Fleisch pneumotachometer. Spirometer hardware and software (Medic al Graphics Corporation [MGC]) comply with 1987 ATS Spirometer performance recommendations and have been validated by an independent testing agency. A different 3.00 Liter calibration syringe was used as a volume standard for this study and the Spirometer software temperature was set to 37ºC. The filed 3.00 L syringe was emptied at varying flows with recovered volumes being within< = +/- 3% of the ideal volume, when each PPFM brand was in-line. Each individual PPFM flow was evaluated, against the MGC (MGC value / Brand value), employing 25 flow challenges using computed Average, Median and SD.
Results: Percentage Differences in Recovered Flows (MGC versus PPFM Brand)
PPFM Brand Name Std Dev % Average % Median %
Astech 7.4- 3.7- 3.3
Assess Low Range16.7- 3.5- 2.0
Assess High Range9.1- 2.9- 4.9
Spir-O-Flow Low 17.5 24.6 24.6
Spir-O-Flow 9.1 8.57.1
MultiSpiro "The PEAK"11.1- 5.6- 6.7
PocketPeak4.7- 7.5- 7.9
Personal Best-Low Range 8.5 -11.1- 9.1
Personal Best-High Range10.3- 4.9- 4.4
Baxter "The PEAK" 16.0 -10.6- 8.8
Conclusion: We conclude there are significant differences in recovered flows, with all brands of PPFMs we evaluated, which may negatively influence (impact upon) patient treatment regimes and outcomes, when serial measurements are evaluated. Additionally, further study is needed to measure what effect repeated (long-term) use, as well as the influence of humidified air, may have on device performance.