Impedance of Laminar Oscillatory Flow Superimposed on a Continuous Turbulent Flow: Application to Respiratory Impedance Measurement

1990 ◽  
pp. 57-64 ◽  
Author(s):  
B. Louis ◽  
D. Isabey
Keyword(s):  
Turbulent Flow ◽  
Oscillatory Flow ◽  
Impedance Measurement ◽  
Respiratory Impedance

Characterization and validation of forced input method for respiratory impedance measurement

1980 ◽  
Vol 40 (1) ◽  
pp. 119-136 ◽  
Author(s):  
E. Delavault ◽  
G. Saumon ◽  
R. Georges
Keyword(s):  
Impedance Measurement ◽  
Respiratory Impedance ◽  
Input Method

Higher order turbulent flow characteristics of oscillatory flow over a wall-mounted obstacle

2018 ◽  
pp. 1-12 ◽  
Author(s):  
Santosh Kumar Singh ◽  
Pankaj Kumar Raushan ◽  
Koustuv Debnath ◽  
Bijoy S. Mazumder
Keyword(s):  
Turbulent Flow ◽  
Oscillatory Flow ◽  
Flow Characteristics ◽  
Higher Order

Influence of upper airway shunt on total respiratory impedance in infants

1999 ◽  
Vol 87 (3) ◽  
pp. 902-909 ◽  
Author(s):  
K. N. Desager ◽  
M. Cauberghs ◽  
J. Naudts ◽  
K. P. van de Woestijne
Keyword(s):  
Respiratory System ◽  
Airway Resistance ◽  
Oscillatory Flow ◽  
Forced Oscillation ◽  
Upper Airway ◽  
Conventional Technique ◽  
Forced Oscillation Technique ◽  
Respiratory Impedance ◽  
Airway Wall ◽  
Shunt Impedance

When input impedance is determined by means of the forced oscillation technique, part of the oscillatory flow measured at the mouth is lost in the motion of the upper airway wall acting as a shunt. This is avoided by applying the oscillations around the subject’s head (head generator) rather than at the mouth (conventional technique). In seven wheezing infants, we compared both techniques to estimate the importance of the upper airway wall shunt impedance (Zuaw) for the interpretation of the conventional technique results. Computation of Zuaw required, in addition, estimation of nasal impedance values, which were drawn from previous measurements (K. N. Desager, M. Willemen, H. P. Van Bever, W. De Backer, and P. A. Vermeire. Pediatr. Pulmonol. 11: 1–7, 1991). Upper airway resistance and reactance at 12 Hz ranged from 40 to 120 and from 0 to −150 hPa ⋅ l−1 ⋅ s, respectively. Varying nasal impedance within the range observed in infants did not result in major changes in the estimates of Zuaw or lung impedance (Zl), the impedance of the respiratory system in parallel with Zuaw. The conventional technique underestimated Zl, depending on the value of Zuaw. The head generator technique slightly overestimated Zl, probably because the pressure gradient across the upper airway was not completely suppressed. Because of the need to enclose the head in a box (which is not required with the conventional technique), the head generator technique is difficult to perform in infants.

scholarly journals Comparison of two devices for respiratory impedance measurement using a forced oscillation technique: basic study using phantom models

2014 ◽  
Vol 64 (5) ◽  
pp. 377-382 ◽  
Author(s):  
Kazuya Tanimura ◽  
Toyohiro Hirai ◽  
Susumu Sato ◽  
Koichi Hasegawa ◽  
Shigeo Muro ◽  
...  
Keyword(s):  
Forced Oscillation ◽  
Impedance Measurement ◽  
Forced Oscillation Technique ◽  
Respiratory Impedance ◽  
Basic Study

Effect of stimulating waveform and of data processing on respiratory impedance measurement

2020 ◽  
Vol 41 (5) ◽  
pp. 055005 ◽  
Author(s):  
Emanuela Zannin ◽  
Bernt B Aarli ◽  
Leonardo Govoni ◽  
Pasquale P Pompilio ◽  
Simonetta Baldi ◽  
...  
Keyword(s):  
Data Processing ◽  
Impedance Measurement ◽  
Respiratory Impedance

Nonlinear fluid systems identified by random noise input

1982 ◽  
Vol 53 (6) ◽  
pp. 1643-1649 ◽  
Author(s):  
E. Delavault ◽  
G. Saumon ◽  
R. Georges
Keyword(s):  
Random Noise ◽  
Nonlinear Coefficient ◽  
Impedance Measurement ◽  
Nonlinear Behavior ◽  
Respiratory Impedance ◽  
Fluid Systems ◽  
Measured System ◽  
The Subject ◽  
Noise Input ◽  
Nonlinear Fluid

The usual impedance measurement by Fourier analysis leads to undetectable errors when applied to nonlinear fluid systems where a nonlinear pressure drop p = K X V2 adds to the linear pressure-flow relationship, but processing series of impedance data with various input levels allows the measurement of such systems. This new method has been tested on simulations, nonlinear resistances, and intubation tubings. It gives accurate estimates of the nonlinear coefficient K together with the true linear impedance of the measured system. This way, the usual respiratory impedance measurement may be applied to intubated patients, as the respiratory impedance of the subject can be separated from the nonlinear behavior of the endotracheal tube or cannula.

Electrode Configurations for a Respiratory Impedance Measurement Suitable for Rate Responsive Pacing.

1986 ◽  
Vol 9 (6) ◽  
pp. 960-964 ◽  
Author(s):  
TIBOR NAPPHOLTZ ◽  
HARRY VALENTA ◽  
JAMES MALONEY ◽  
TONY SIMMONS
Keyword(s):  
Impedance Measurement ◽  
Respiratory Impedance ◽  
Rate Responsive

An Introduction to Turbulent Flow

2000 ◽  
Author(s):  
Jean Mathieu ◽  
Julian Scott
Keyword(s):  
Turbulent Flow
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