A tracking impedance estimation technique was developed to follow the changes in total respiratory impedance (Zrs) during slow total lung capacity maneuvers in six anesthetized and mechanically ventilated BALB/c mice. Zrs was measured with the wave-tube technique and pseudorandom forced oscillations at nine frequencies between 4 and 38 Hz during inflation from a transrespiratory pressure of 0-2...

Asthma and COPD are chronic respiratory diseases that fluctuate widely with regard to clinical symptoms and airway obstruction, complicating treatment and prediction of exacerbations. Time series of respiratory impedance obtained by the forced oscillation technique are a convenient tool to study the respiratory system with high temporal resolution. In previous studies it was suggested that powe...

Malnutrition in patients with severe respiratory insufficiency can lead to severe complications, justifying the use of objective nutritional assessment techniques, such as bioelectrical impedance analysis (BIA), which is an easy, noninvasive method of measuring body composition. The purpose of this study was to develop, and validate against dual-energy X-ray absorptiometry (DXA), a BIA formula ...

Electrical Impedance Tomography (EIT) has successive wide range in impedance imaging, but still it is difficult to extract cardiac-related conductivity changes and respiratory-related conductivity changes in spontaneous breathing subjects. Quite a few methods are attempted to extract these two signals such as electrocardiogram gated averaging, frequency domain filtering and principal component ...

Impedance cardiography is a noninvasive technique for monitoring stroke volume (SV), based on sensing variation in the thoracic impedance due to blood flow. In this technique, first derivative of impedance (dz/dt) is used to calculate two parameters: ventricular ejection time and (-dz/dt)max. Respiration and motion artifacts cause base line drift in the sensed impedance waveform, and this resul...

The present study describes a device (AMD43) for ambulatory measurement of respiration rate and respiratory sinus arrhythmia from the combined electrocardiogram (ECG) and thoracic impedance signals. Respiratory time intervals derived from this ambulatory device closely corresponds to those derived from simultaneous recordings with a 'classical' laboratory set-up. Good cross-instrument compariso...

An objective method of extracting respiratory data from lung images is presented, together with a technique for automatically generating regions of interest delineating the anterior and posterior regions of the lungs. The method is used to extract data on the change in lung impedance with frequency, and on calculated Cole parameters, from 19 normal neonates (gestational age 32 to 42 weeks) and ...