Comparison of Mini-Wright Peak Flow Meter and Microplus Pocket Spirometer in Measuring Peak Expiratory Flow Rate

Rah, Young Ho; Bae, Chong Woo; Chung, Sa Jun

Abstract

PURPOSE
Peak expiratory flow rate (PEFR) monitoring plays an important role in the diagnosis of airway obstruction and management of patients with bronchial asthma. This study compared the PEFR taken by a Microplus pocket spirometer and mini-Wright peak flow meter by assessing the extent of agreement between the instruments and the repeatability of measurements with each instrument.
METHODS
Eighty healthy children (age 11-12 years, 43 females, 37 males) performed three PEFR maneuvers on the Microplus pocket spirometer and on the mini-Wright peak flow meter in a random order. Agreement and reproducibility between the two instruments were assessed by the statistical methods proposed by Bland and Altman.
RESULTS
Seventy six (95%) of the PEFR taken by the mini-Wright peak flow meter were higher than that of Microplus pocket spirometer. The 95% limits of agreements (mean difference+/-2SD) between each instrument were very wide (2.7 to 144.3 L/min). The repeatability coefficient for the mini-Wright peak flow meter was 27 L/min and for the Microplus pocket spirometer was 33.5 L/min. Analysis by sex and order of usage did not show any significant differences.
CONCLUSION
The limit of agreement between the Microplus pocket spirometers and the mini-Wright peak flow meter was too wide to use interchangeably.