Estimation of respiratory impedance at low frequencies during spontaneous breathing using the forced oscillation technique

2014 ◽  
Author(s):  
Hannes Maes ◽  
Gerd Vandersteen ◽  
Clara Ionescu
Keyword(s):  
Spontaneous Breathing ◽  
Forced Oscillation ◽  
Forced Oscillation Technique ◽  
Respiratory Impedance ◽  
Low Frequencies

Measurement of total respiratory impedance in calves by the forced oscillation technique

1988 ◽  
Vol 64 (5) ◽  
pp. 1786-1791 ◽  
Author(s):  
P. Gustin ◽  
A. R. Dhem ◽  
F. Lomba ◽  
P. Lekeux ◽  
K. P. Van de Woestijne ◽  
...  
Keyword(s):  
Resonant Frequency ◽  
Fourier Analysis ◽  
Respiratory System ◽  
Pressure Wave ◽  
Forced Oscillation ◽  
Forced Oscillation Technique ◽  
Respiratory Impedance ◽  
Upper Airways ◽  
Low Frequencies ◽  
Spontaneously Breathing

We have determined the resistance (Rrs) and the reactance (Xrs) of the total respiratory system in unsedated spontaneously breathing calves at various frequencies. A pseudorandom noise pressure wave was produced at the nostrils of the animals by means of a loudspeaker adapted to the nose by a tightly fitting mask. A Fourier analysis of the pressure in the nostrils and flow signals yielded mean Rrs and Xrs, over 16 s, at frequencies of 2–26 Hz. A good correlation was found between values of pulmonary resistances measured by the isovolume method at the respiratory frequency of animals and values obtained at a frequency of 6 Hz by use of our technique. The linearity of the respiratory system, the reproducibility of the technique, and the effects of upper airways on results have been studied. In healthy calves, Rrs increases with frequency. Mean resonant frequency is 7.5 Hz. Bronchospasm was induced in six calves by administration of intravenous organophosphates. Rrs tended to decrease with increasing frequency. Resonant frequency exceeded 26 Hz. All parameters returned to initial values after administration of atropine. In healthy calves, atropine produces a decrease in Rrs, especially at low frequencies. Values of resonant frequency are not modified.

Optimized estimation of respiratory impedance by signal averaging in the time domain

1992 ◽  
Vol 73 (3) ◽  
pp. 1181-1189 ◽  
Author(s):  
R. Farre ◽  
M. Rotger ◽  
D. Navajas
Keyword(s):  
Time Domain ◽  
Forced Oscillation ◽  
Computing Time ◽  
Forced Oscillation Technique ◽  
Respiratory Impedance ◽  
Signal Averaging ◽  
Low Frequencies ◽  
Time Domain Signal ◽  
On Line ◽  
The Time Domain

The spontaneous breathing of a subject during measurements of respiratory impedance (Zrs) by the forced oscillation technique (FOT) induces errors that result in biased impedance estimates, especially at low frequencies. Although in standard measurements this bias may be avoided by using special impedance estimators, there are two applications of FOT for which such estimators are not useful: when a head generator is used and when measurements are made during intubation. In this paper we describe a data-processing procedure for unbiased impedance estimation for all FOT setups. The proposed estimator (Z) was devised for pseudorandom excitation and is based on time-domain signal averaging before frequency analysis. The performance of estimator Z was first analyzed by computer simulation of a head generator setup and a setup including an endotracheal tube to measure (2–32 Hz) a resistance-inertance-elastance model mimicking Zrs of a healthy subject. Second, Z was assessed during real measurements in 16 healthy subjects. The results obtained in the simulation (e.g., error in elastance was reduced from 15.6% with most conventional estimators to 3.3% with Z in simulation of head generator setup) and in the measurements in subjects (differences of less than 1.6% between Z and a reference) confirmed the theoretical lack of bias of Z and its practical suitability for the different FOT setups. In addition to its applicability in the situations in which no other unbiased estimators are available, estimator Z is also advantageous in most conventional applications of FOT, since it requires much less computing time and thus allows on-line Zrs measurements.

Reference values for respiratory impedance measured by the forced oscillation technique in adult men and women

2018 ◽  
Vol 12 (6) ◽  
pp. 2126-2135 ◽  
Author(s):  
Fernando Carlos Vetromille Ribeiro ◽  
Agnaldo José Lopes ◽  
Pedro Lopes de Melo
Keyword(s):  
Reference Values ◽  
Forced Oscillation ◽  
Forced Oscillation Technique ◽  
Respiratory Impedance ◽  
Men And Women ◽  
Adult Men

Respiratory resistance by end-inspiratory occlusion and forced oscillations in intubated patients

1996 ◽  
Vol 80 (4) ◽  
pp. 1105-1111 ◽  
Author(s):  
L. Beydon ◽  
P. Malassine ◽  
A. M. Lorino ◽  
C. Mariette ◽  
F. Bonnet ◽  
...  
Keyword(s):  
Forced Oscillation ◽  
Forced Oscillations ◽  
Forced Oscillation Technique ◽  
Respiratory Impedance ◽  
Respiratory Resistance ◽  
Airway Occlusion ◽  
Residual Capacity ◽  
Occlusion Technique ◽  
Air Compression ◽  
Good Agreement

Measurement of respiratory impedance by the forced oscillation technique (FOT) in intubated patients requires corrections for the flow-dependent resistance, inertance, and air compression inside the endotracheal tube (ETT). Recently, we published a method to correct respiratory impedance for the mechanical contribution of the ETT. To validate this correction, we compared the respiratory resistance obtained with this method (Rfo) to the intrinsic (Rmin) and total resistances (RT) measured by the airway-occlusion technique (OCT) in 16 intubated sedated paralyzed ventilated patients. The FOT was applied at functional residual capacity in the 4- to 32-Hz frequency range, whereas the OCT was performed at the end of a normal constant-flow inspiration. Rmin corrected with Rfo measured at 16 and 32 Hz [Rfo(16) = 1.10 x Rmin + 0.10 cmH2O.s.l-1, r = 0.96, P < 0.001; Rfo(32) = 0.93 x Rmin + 0.72 cmH2O.s.l-1, r = 0.97, P < 0.001]. RT corrected with Rfo at 4 Hz [Rfo(4) = 1.11 x RT - 1.48 cmH2O.s.l-1; = 0.92; P < 0.001]. We conclude that the FOT improved by correction for the behavior of the ETT is in good agreement with the OCT in intubated patients.

scholarly journals Regression equations of respiratory impedance of Indian adults measured by forced oscillation technique

Lung India ◽  
2020 ◽  
Vol 37 (1) ◽  
pp. 30 ◽  
Author(s):  
Sajal De ◽  
Nalok Banerjee ◽  
GaganDeep Singh Kushwah ◽  
Dharmendra Dharwey
Keyword(s):  
Forced Oscillation ◽  
Forced Oscillation Technique ◽  
Regression Equations ◽  
Respiratory Impedance

Respiratory impedance measured by forced oscillation technique in young healthy preschool children

2017 ◽  
Vol 139 (2) ◽  
pp. AB200
Author(s):  
Pinyapa Mukdjindapa ◽  
Wiparat Manuyakorn ◽  
Suwat Benjaponpitak ◽  
Wasu Kamchaisatian
Keyword(s):  
Preschool Children ◽  
Forced Oscillation ◽  
Forced Oscillation Technique ◽  
Respiratory Impedance

scholarly journals Influence of cheek support on respiratory impedance measured by forced oscillation technique

SpringerPlus ◽  
2013 ◽  
Vol 2 (1) ◽  
pp. 342 ◽  
Author(s):  
Akemi Uchida ◽  
Satoru Ito ◽  
Béla Suki ◽  
Hiroki Matsubara ◽  
Yoshinori Hasegawa
Keyword(s):  
Forced Oscillation ◽  
Forced Oscillation Technique ◽  
Respiratory Impedance

scholarly journals Frequency dependence of forced oscillatory respiratory mechanics in horses with heaves

1997 ◽  
Vol 82 (3) ◽  
pp. 983-987 ◽  
Author(s):  
S. S. Young ◽  
D. Tesarowski ◽  
L. Viel
Keyword(s):  
Frequency Dependence ◽  
Respiratory Mechanics ◽  
Forced Oscillation ◽  
Element Model ◽  
Airway Disease ◽  
Allergic Airway Disease ◽  
Forced Oscillation Technique ◽  
Respiratory Impedance ◽  
Antigenic Challenge ◽  
Small Airway Obstruction

Young, S. S., D. Tesarowski, and L. Viel. Frequency dependence of forced oscillatory respiratory mechanics in horses with heaves. J. Appl. Physiol. 82(3): 983–987, 1997.—The effect of measurement frequency on respiratory mechanics was investigated in six horses with reversible allergic airway disease. Total respiratory impedance was measured at 1.5, 2.0, 3.0, and 5.0 Hz by using the forced oscillation technique with the horses in remission, after acute antigenic challenge producing clinical heaves, and with heaves but after the administration of 2 mg fenoterol by inhalation. The slopes of the magnitude (‖Zrs‖) and real part (R) of total respiratory impedance over the frequency range 1.5–3 Hz changed significantly after antigenic challenge and fenoterol. The ratio of R at 2 Hz to R at 3 Hz, however, discriminated better among the three conditions. Compliance and resonant frequency (calculated by using a three-element model) changed significantly after antigenic challenge and fenoterol, but inertance did not. We concluded that horses with heaves showed frequency dependence of R and ‖Zrs‖ at frequencies up to 3 Hz and that parameters derived from a three-element model were useful indicators of small airway obstruction in the horse.

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