background the forced oscillation technique (fot) is a non-invasive means of measuring respiratory resistance and reactance. we tested our hypothesis that endotracheal intubation would cause more substantial preoperative increases in fot parameters than a supraglottic airway device (sgd). methods forty patients requiring general anesthesia and mechanical ventilation for transurethral bladder tu...

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OBJECTIVES Several studies have confirmed the high potential of the forced oscillation technique for the assessment of respiratory modifications related to chronic obstructive pulmonary disease. However, most of these studies did not employ within-breath analyses of the respiratory system. The aim of this study is to analyze respiratory impedance alterations in different phases of the respirato...

Inductive plethysmography and impedance pneumography are two non-invasive technologies for measuring respiratory function. The following report describes the advantages of inductive plethysmography, which include greater accuracy and sensitivity; the ability to assess thoracoabdominal coordination; and the minimization of motion artifact. Together, these properties make inductive plethysmograph...

The design of the mathematical model of the respiratory system is described in the study. The model has been designed using an electro-acoustic analogy and geometrical dimensions of the morphological models of the respiratory system. The dependence of the geometrical dimension of the airways upon the total lung impedance is studied. Geometrical dimensions of adult respiratory system and neonate...

Thoracic impedance is modulated by events within the respiratory cycle, which represents a source of "noise" in impedance cardiography. Respiration itself, however, is a physiological rhythm of interest to psychophysiologists. We report here methods and validation for deriving impedance pneumographic measures of respiration from impedance cardiography signals, based on standard tetrapolar band ...

This paper will present a comparison in terms of respiratory impedance values, between a symmetric morphologic structure and an asymmetric structure of the airways. The model of the respiratory tree is introduced as a recurrent, fractal structure. The intrinsic properties posed by such a system affect directly the respiratory impedance, in a frequency dependent manner. It is therefore important...

BACKGROUND In infants the impedance of the nasal pathways (Zn) is a significant proportion of the total respiratory impedance (Zrs). METHODS In 11 infants Zrs was partitioned into Zn and lower respiratory system impedance (Zlrs) using a nasal catheter. A low frequency oscillatory signal (0.5-20 Hz) was applied during a pause in breathing to obtain the impedance spectra. A model of the respira...

Measurement of respiratory impedance (Zrs) in intubated patients requires corrections for flow-dependent resistance and air compression inside the endotracheal tube (ET). The purpose of this study was to test a new correction technique for these effects. We therefore studied 110 patients in two conditions: breathing normally (C1), or breathing through an ET placed at the mouth (C2). In C1, we m...

Submitting a physical system to forced oscillations is a very general approach to investigation of its structure and/or properties. Its application to respiratory mechanics was first proposed by DuBors et al. in 1956 [1], but it has also been used in other fields of respiratory physiology, e.g. to investigate the control of breathing and the response to exercise. As used in respiratory mechanic...