Thoracic impedance measurement for lung function evaluation

As the Golden Standard for clinical pulmonary function examination, spirometer examination requires a facemask and nose clip to be worn. It generally takes half an hour or more to examine one patient. In addition, it needs the operator having rich experiences and the patients to cooperate well. A more convenient effective evaluation tool is strongly demanded in routine pulmonary function examination. Existing research results suggest that, thoracic impedance varies with vital capacity and shows good correlation with vital capacity. Thoracic impedance measurement technology has been studied in this paper for lung function evaluation purpose. Compound electrodes and in-house developed impedance measurement system are used to investigate the electrode position and the most sensitive measurement frequency. Comparison test with pneumatometer shows the thoracic impedance variation consists with vital capacity very well but with more details. The tests show that thoracic impedance is feasible for lung function evaluation. The experimental results are presented and challenges are discussed.