Forced oscillatory impedance of the respiratory system at low frequencies

Hantos, Zoltán; Daróczy, Bálint; Suki, Bélâ; Galgóczy, G.; Csendes, Tibor

doi:10.1152/jappl.1986.60.1.123

Cited by 113 publications

(73 citation statements)

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“…FOT and interrupter technique both measure R rs , which includes additional resistances of lung and thoracic tissue. Table 1 shows summarized and rounded estimates for fractions of flow resistance from studies on healthy individuals, in which measurements were performed during spontaneous breathing through the mouth at FRC and V T in the sitting position~Bachofen, 1966; Barnas et al, 1992;Ferris, Mead, & Opie, 1964;Hantos, Daróczy, Suki, Galgoczy, & Csendes, 1986;Hyatt & Wilcox, 1961;Jaeger & Otis, 1964;McIlroy, Mead, Selverstone, & Radford, 1955!. 3 The estimates were obtained by different combinations of these techniques with more invasive methods such as the esophagus balloon catheter or pressure recording via a needle inserted into the extrathoracic part of the trachea. Most authors reported a considerable interindividual variation in estimates, probably due to anatomic differences.…”

Section: Comparison Between Methods Of Airflow Resistance Measurementmentioning

confidence: 99%

Guidelines for mechanical lung function measurements in psychophysiology

Ritz¹,

Dahme²,

DuBois³

et al. 2002

Psychophysiol.

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Studies in psychophysiology and behavioral medicine have uncovered associations among psychological processes, behavior, and lung function. However, methodological issues specific to the measurement of mechanical lung function have rarely been discussed. This report presents an overview of the physiology, techniques, and experimental methods of mechanical lung function measurements relevant to this research context. Techniques to measure lung volumes, airflow, airway resistance, respiratory resistance, and airflow perception are introduced and discussed. Confounding factors such as ventilation, medication, environmental factors, physical activity, and instructional and experimenter effects are outlined, and issues specific to children and clinical groups are discussed. Recommendations are presented to increase the degree of standardization in the research application and publication of mechanical lung function measurements in psychophysiology.Descriptors: Mechanical lung function, Airway resistance, Respiratory resistance, Spirometry, Pneumotachography, Body plethysmography, Forced oscillation technique, Interrupter technique, Respiratory perception Despite long-standing interest in respiration by psychophysiologists, it is surprising that little attention has been directed to methodological issues of specific measurement techniques in this area. Although occasional textbook chapters have been devoted to respiration measurements, a more in-depth discussion of techniques dealing with the assessment of mechanical lung function is still missing. Mechanical lung function relates to lung volumes and airflow through the respiratory system as well as the pressurevolume and pressure-flow characteristics as indicators of elastic and resistive properties of the airways, lungs, and chest wall. In clinical practice, mechanical lung function measures are widely used for the diagnosis and management of various pulmonary diseases, most importantly bronchial asthma and chronic obstructive pulmonary disease~COPD!. In psychophysiology and behavioral medicine, potential associations between psychological or behavioral processes and mechanical lung function offer an exciting perspective both for basic research and clinical application. Due to the particular importance of the vagal system in governing airway function, the airways offer a unique window into the autonomic nervous system regulation of behavior, emotion, and cogThomas Ritz acted as coordinator and contributor to this report. The authorship of the other contributors was determined by alphabetical order. Different sections were drafted by individual contributors, submitted to internal peer review, and revised until consensus was achieved. We are indebted to

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Section: Comparison Between Methods Of Airflow Resistance Measurementmentioning

confidence: 99%

Guidelines for mechanical lung function measurements in psychophysiology

Ritz¹,

Dahme²,

DuBois³

et al. 2002

Psychophysiol.

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“…The most common is to excite the respiratory system with small amplitude pseudorandom noise using a loud-speaker. 9 While straightforward, this technique has several technical and clinical drawbacks. It requires highperformance subwoofer speakers relatively free of harmonic distortion.…”

Section: Introductionmentioning

confidence: 99%

“…3,5 Finally, this approach requires considerable subject cooperation. Awake subjects require training to achieve the necessary prolonged periods of apnea and respiratory muscle relaxation, 9 which makes the method impractical for routine use in patients with impaired lung function. In anesthetized and paralyzed patients, this technique usually requires temporary interruption of artificial ventilatory support.…”

Section: Introductionmentioning

confidence: 99%

Servo-Controlled Pneumatic Pressure Oscillator for Respiratory Impedance Measurements and High-Frequency Ventilation

Kaczka¹,

Lutchen²

2004

Annals of Biomedical Engineering

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Abstract-The ability to provide forced oscillatory excitation of the respiratory system can be useful in mechanical impedance measurements as well as high frequency ventilation (HFV). Experimental systems currently used for generating forced oscillations are limited in their ability to provide high amplitude flows or maintain the respiratory system at a constant mean pressure during excitation. This paper presents the design and implementation of a pneumatic pressure oscillator based on a proportional solenoid valve. The device is capable of providing forced oscillatory excitations to the respiratory system over a bandwidth suitable for mechanical impedance measurements and HVF. It delivers high amplitude flows (>1.4 l/s) and utilizes a servo-control mechanism to maintain a load at a fixed mean pressure during simultaneous oscillation. Under open-loop conditions, the device exhibited a static hysteresis of approximately 7%, while its dynamic magnitude and phase responses were flat out to 10 Hz. Broad-band measurement of total harmonic distortion was approximately 19%. Under closed-loop conditions, the oscillator was able to maintain a mechanical test load at both positive and negative mean pressures during oscillatory excitations from 0.1 to 10.0 Hz. Impedance of the test load agreed closely with theoretical predictions. We conclude that this servo-controlled oscillator can be a useful tool for respiratory impedance measurements as well as HFV.

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“…A previous study showed that extrathoracic airway wall structures have negligible impact on the measurement of the tissue properties in infants using the LFOT, after correction for the parallel shunt imposed by the equipment deadspace and face mask, and when firm support of the cheeks and jaw are maintained throughout the measurement (13). This can be explained by the relative rigidity of the nasal passages compared with the oral structures, and also by the similar frequency dependencies of Z rs and the upper airway wall impedance (10) in the low-frequency region. On the other hand, inclusion of the nasal passage in the impedance measurement exerts a more marked effect on airway resistance and inertance (13), although to a lesser extent than observed during forced oscillations at higher frequencies (27).…”

Section: Discussionmentioning

confidence: 93%

“…At low frequencies, the resistance and reactance decrease nearly hyperbolically with increasing frequency. At higher frequencies, the tissue properties become less important and the largely frequencyindependent airway properties of resistance and inertance dominate (10). Variables representing the mechanical properties of the airways (resistance and inertance) and the tissues (resistance or "damping" and the elastance) can be obtained by fitting a model to the impedance spectra (9).…”

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confidence: 99%