Reliability and Validity of an Electronic Inspiratory Loading Device for Assessing Pulmonary Function in Patients with COPD

Objective: The purpose of this study is to prove the reliability and validity of the Power breath K5 and to compare it with pony FX. Power breathe K5 is one type of device can assess automatically Maximum inspiratory pressure (MIP), Peak inspiratory pressure, Peak inspiratory flow (PIF). Design: Cross-sectional study. Methods: Thirty-five COPD patients participated in the test to investigate for the intra relater reliability and concurrent validity. The tests MIP, Vital capacity (VC), PIF were measured by Powerbreathe K5 and Pony Fx. Data was analyzed by intraclass correlation reliability (ICC) value and a standard error of measurement and Bland-Altman plots for reliability and pearson correlation for validity. Results: Intra rater reliability of the Powerbreathe K5 was very high at MIP (ICC=0.977 95%CI 0.956~0.989, SEM=8.665, MDC=0.295), PIF (ICC=0.966 95%CI 0.933~0.93, SEM=8.665, MDC=0.295), VC (ICC=0.949 95CI 0.902~0.974, SEM=0.042, MDC=0.116). The Powerbreath K5 was significant correlation compared with Pony Fx in assessment for MIP (r=0.971, p<0.05) and vital capacity (r=0.534, p<0.05). Conclusion: In this study, We investigated the clinical usefulness of the Powerbreath K5 in evaulating the MIP, VC and PIF with COPD patients with high reliability and validity.