Use of the forced-oscillation technique to estimate spirometry values
Received 11 June 2017
Accepted for publication 29 August 2017
Published 3 October 2017 Volume 2017:12 Pages 2859—2868
Checked for plagiarism Yes
Review by Single anonymous peer review
Peer reviewer comments 2
Editor who approved publication: Dr Richard Russell
Shoichiro Yamamoto,1 Seigo Miyoshi,1 Hitoshi Katayama,1 Mikio Okazaki,2 Hisayuki Shigematsu,2 Yoshifumi Sano,2 Minoru Matsubara,3 Naohiko Hamaguchi,1 Takafumi Okura,1 Jitsuo Higaki1
1Department of Cardiology, Pulmonology, Hypertension, and Nephrology, 2Department of Cardiovascular and Thoracic Surgery, Ehime University Graduate School of Medicine, Toon, 3Department of Internal Medicine, Sumitomo Besshi Hospital, Niihama, Japan
Purpose: Spirometry is sometimes difficult to perform in elderly patients and in those with severe respiratory distress. The forced-oscillation technique (FOT) is a simple and noninvasive method of measuring respiratory impedance. The aim of this study was to determine if FOT data reflect spirometric indices.
Patients and methods: Patients underwent both FOT and spirometry procedures prior to inclusion in development (n=1,089) and validation (n=552) studies. Multivariate linear regression analysis was performed to identify FOT parameters predictive of vital capacity (VC), forced VC (FVC), and forced expiratory volume in 1 second (FEV1). A regression equation was used to calculate estimated VC, FVC, and FEV1. We then determined whether the estimated data reflected spirometric indices. Agreement between actual and estimated spirometry data was assessed by Bland–Altman analysis.
Results: Significant correlations were observed between actual and estimated VC, FVC, and FEV1 values (all r>0.8 and P<0.001). These results were deemed robust by a separate validation study (all r>0.8 and P<0.001). Bias between the actual data and estimated data for VC, FVC, and FEV1 in the development study was 0.007 L (95% limits of agreement [LOA] 0.907 and -0.893 L), -0.064 L (95% LOA 0.843 and -0.971 L), and -0.039 L (95% LOA 0.735 and -0.814 L), respectively. On the other hand, bias between the actual data and estimated data for VC, FVC, and FEV1 in the validation study was -0.201 L (95% LOA 0.62 and -1.022 L), -0.262 L (95% LOA 0.582 and -1.106 L), and -0.174 L (95% LOA 0.576 and -0.923 L), respectively, suggesting that the estimated data in the validation study did not have high accuracy.
Conclusion: Further studies are needed to generate more accurate regression equations for spirometric indices based on FOT measurements.
Keywords: forced expiratory volume in 1 second, forced-oscillation technique, forced vital capacity, spirometry, vital capacity