title: Effects of the nasal passage on forced oscillation lung function measurements.
abstract: The forced oscillation technique (FOT) is a non-invasive pulmonary function test which is based on the measurement of respiratory impedance. Recently, promising results were obtained by the application of FOT on patients with respiratory failure and obstructive sleep apnea (OSA). By using a nasal mask instead of a mouthpiece, the influences of the nasal passage and upper shunt alter the measured mechanical impedance. In this paper, we investigated the effects of the nasal passage and mask on FOT measurements from eight healthy subjects. A method for flow correction has been developed, which contains a pressure-flow characteristics compensation of the undetermined flow leakage at the face-mask interface. Impedance calculation and parameter estimation were performed in the frequency domain using fast Fourier transform (FFT). Average nasal parameters were Rnaw=4.07 cmH2O/l/s for resistance and Lnaw=0.0183 cmH2O/l/s2 for inertance. On average, the nasal resistance corresponds to 65.85% of the total resistance.
authors.affiliation: .
authors.forename: Chuong
authors.initials: C
authors.lastname: Ngo
authors.affiliation: .
authors.forename: Karl
authors.initials: K
authors.lastname: Krüger
authors.affiliation: .
authors.forename: Thomas
authors.initials: T
authors.lastname: Vollmer
authors.affiliation: .
authors.forename: Stefan
authors.initials: S
authors.lastname: Winter
authors.affiliation: .
authors.forename: Bernhard
authors.initials: B
authors.lastname: Penzlin
authors.affiliation: .
authors.forename: Sylvia
authors.initials: S
authors.lastname: Lehmann
authors.affiliation: .
authors.forename: Steffen
authors.initials: S
authors.lastname: Leonhardt
authors.affiliation: .
authors.forename: Berno
authors.initials: B
authors.lastname: Misgeld
mesh_terms: D017097:Electric Impedance; D006801:Humans; D008170:Lung Compliance / Q000502:physiology*; D012129:Respiratory Function Tests / Q000295:instrumentation* / Q000379:methods
keywords: forced oscillation technique; modeling; nasal mask; obstructive sleep apnea; parameter fitting; pulmonary function test; respiratory impedance