Electrical impedance tomography (EIT) is an emerging new imaging modality not yet routinely used in a clinical setting. The generation of EIT scans is based on the non-invasive measurement of electrical properties of tissues which does not require the use of radiation. Thoracic EIT examinations have been shown to track changes in regional lung volumes at scan rates of up to 40-50 scans/s. Exper...

Total respiratory input impedance (Zrs) measured by forced excitation may be computed easily from pressure and flow measurements recorded at the airway opening. The purpose of this paper was to analyse how the information provided by Zrs may be used for monitoring ventilatory mechanics during high frequency oscillatory ventilation (HFOV). We measured impedance (0.125-32 Hz) in six dogs, and in ...

In a placebo controlled study the effects of 6 weeks' treatment with inhaled budesonide (1.6 mg daily) on the impedance of the respiratory system, spirometry and symptom scores were evaluated in 35 patients with chronic bronchitis with forced expiratory volume in one second (FEV1) greater than or equal to 70% predicted. Thirty patients completed the study. No statistically significant differenc...

Past studies in humans and other species have revealed the presence of resonances and antiresonances, i.e., minima and maxima in respiratory system impedance (Zrs), at frequencies much higher than those commonly employed in clinical applications of the forced oscillation technique (FOT). To help understand the mechanisms behind the first occurrence of antiresonance in the Zrs spectrum, the freq...

Because of the minimal demand for cooperation by the subject, the forced oscillation technique is increasingly employed in routine lung function testing. However, comprehensive and device-independent values of respiratory impedance at baseline and after bronchodilation have not been established for healthy adults. The aim of this multicentre study was to collect impedance data from 4 to 26 Hz i...

Measuring lung function in mice is essential for establishing the relevance of murine models to human lung disease. However, making such measurements presents particular technical challenges due to the small size of the animal, particularly with regard to the measurement of respiratory flows. In this review, we examine the various methods currently available for assessment of lung function in m...

The forced oscillation technique (FOT) can measure respiratory mechanics and has attracted attention in chronic obstructive pulmonary disease (COPD). We aimed to evaluate the effects of only indacaterol and tiotropium monotherapies on airflow limitation and respiratory impedance. Pulmonary function tests, COPD assessment test (CAT), and multifrequency FOT with MostGraph-01 were performed at the...

Sarafotoxins (SRTX) are endothelin-like peptides extracted from the venom of snakes belonging to the Atractaspididae family. A recent in vivo study on anesthetized and ventilated animals showed that sarafotoxin-b (SRTX-b), extracted from the venom of Atractaspis engaddensis, decreases cardiac output by inducing left ventricular dysfunction while sarafotoxin-m (SRTX-m), extracted from the venom ...

Optimization of cerebral blood flow (CBF) is the cornerstone of clinical management in a number of neurologic diseases, most notably ischemic stroke. Intrathoracic pressure influences cardiac output and has the potential to impact CBF. Here, we aim to quantify cerebral hemodynamic changes in response to increased respiratory impedance (RI) using a non-invasive respiratory device. We measured ce...

Physiological and clinical studies have shown that the standard method of measuring respiratory impedance by forced oscillation leads to less efficient control of the upper airway shunt effect than the head generator method. To test the effects of these two techniques in epidemiological studies, we compared, in a sample of 73 French agricultural workers, the values obtained with each method for...