Systematic and Random Errors in the Determination of Respiratory Impedance by Means of the Forced Oscillation Technique: A Theoretical Study

1983 ◽  
Vol BME-30 (10) ◽  
pp. 642-651 ◽  
Author(s):  
H. Franken ◽  
J. Clement ◽  
K. P. Van de Woestijne
Keyword(s):  
Theoretical Study ◽  
Forced Oscillation ◽  
Forced Oscillation Technique ◽  
Respiratory Impedance ◽  
Random Errors ◽  
Systematic And Random Errors

Statistics and parallaxes

1978 ◽  
Vol 48 ◽  
pp. 7-29
Author(s):  
T. E. Lutz
Keyword(s):  
Experimental Design ◽  
Statistical Methods ◽  
Review Paper ◽  
Systematic Errors ◽  
Past Experience ◽  
Random Errors ◽  
Trigonometric Parallaxes ◽  
Systematic And Random Errors

This review paper deals with the use of statistical methods to evaluate systematic and random errors associated with trigonometric parallaxes. First, systematic errors which arise when using trigonometric parallaxes to calibrate luminosity systems are discussed. Next, determination of the external errors of parallax measurement are reviewed. Observatory corrections are discussed. Schilt’s point, that as the causes of these systematic differences between observatories are not known the computed corrections can not be applied appropriately, is emphasized. However, modern parallax work is sufficiently accurate that it is necessary to determine observatory corrections if full use is to be made of the potential precision of the data. To this end, it is suggested that a prior experimental design is required. Past experience has shown that accidental overlap of observing programs will not suffice to determine observatory corrections which are meaningful.

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

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.

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

A modified forced oscillation technique for measurements of respiratory resistance

1977 ◽  
Vol 42 (4) ◽  
pp. 650-655 ◽  
Author(s):  
H. Aronsson ◽  
L. Solymar ◽  
J. Dempsey ◽  
J. Bjure ◽  
T. Olsson ◽  
...  
Keyword(s):  
Forced Oscillation ◽  
Signal To Noise Ratio ◽  
Optimization Technique ◽  
Forced Oscillation Technique ◽  
Respiratory Resistance ◽  
Asthmatic Children ◽  
The Difference ◽  
Resistance Value ◽  
Automated Determination

We present a modification of forced oscillation technique for automated determination of total respiratory resistance during inspiration. The modifications consist of a computerized signal averaging and an optimization technique in the assessment of the resistance value. Thereby a favorable signal-to-noise ratio is obtained, allowing very low superimposed pressure oscillations. The method is validated by comparison with a conventional esophageal balloon method, by estimating added mechanical resistances in healthy subjects and by measuring the effect of bronchodilation in asthmatic children. The coefficient of variation as obtained from day-to-day measurements was about 7%. Mechanical resistances, estimated as the difference in total resistance with and without external resistance, were within 7% of their values determined for the resistances alone. A significant decrease in resistance was obtained in each of the asthmatic children following bronchodilation.

Shunt effect of gas compression inside pneumotachographs during forced oscillations

1991 ◽  
Vol 70 (1) ◽  
pp. 143-151 ◽  
Author(s):  
B. Louis ◽  
A. Harf ◽  
H. Lorino ◽  
D. Isabey
Keyword(s):  
Frequency Response ◽  
High Frequency ◽  
Forced Oscillation ◽  
Series Resistance ◽  
Forced Oscillations ◽  
Respiratory Impedance ◽  
Gas Compression ◽  
Normal Humans ◽  
Oscillation Method

Determination of the frequency response of pneumotachographs is needed whenever they are used to measure high-frequency flows, such as in the forced oscillation method. When screen and capillary pneumotachographs are calibrated using an adiabatic compression in a closed box as a reference impedance, they can be adequately described by a series of inertial-resistive elements. However, this type of reference impedance strongly differs from the actual respiratory impedance (ZL). We studied the frequency response of pneumotachographs up to 250 Hz in reference to the impedance of a compressible gas oscillating in a long tube, taken as a more generalizable model of actual ZL. We found that, with this device, the series resistance-inertance models fail to describe the frequency response of the pneumotachograph. However, when compressible effects in the pneumotachograph are taken into account by adding to the resistive models a compliance (Cpn) corresponding to the compression in half of the inner volume of the pneumotachograph, the agreement with experiments becomes satisfactory. Gas compression-related phenomena were demonstrated to be negligible only when the parameter omega Cpn magnitude of ZL is much smaller than 1 (omega pulsation). Results obtained in normal humans have shown that such a correction is required above 100 Hz. Similar correction at lower frequency might also be necessary in cases of large respiratory impedance (e.g., babies, subjects with pathological lungs, and intubated subjects).

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