| 摘要 |
<p>Four surface electrodes are used in the Focused Impedance method (FIM) in order to monitor the localized impedance respiratory rate within the thoracic region of a human body. This method has a potential application in localized lung ventilation studies and in the diagnosis of pulmonary diseases. In this method respiratory rate waveform are observed (around thorax) in terms of electrical impedance using the four electrode FIM electrical circuit. For this, the FIM values at full inspiration and full expiration waveform are observed and compared under rest and exercise conditions. It is expected that the change in respiratory rate depends upon age and condition (rest or exercise) of subject and variation in respiratory rate described the different pulmonary diseases. The change in the air contents during ventilation in different region of the lungs is different depending on the anatomical structure of the lungs. The expected change in FIM respiratory rate due to change in air content is visible from different waveforms (waveform1-4). The waveform 1 (in the rest position) is obtained near to false ribs 8-10 on right side of thoracic region in between the intercostals space of the ribs. The second waveform is also in the rest position and is obtained near to the true ribs 3-5 on the right side of thoracic region in between the intercostals space of the ribs. The third waveform is collected from true ribs 4-7 of right side of thoracic region in the rest position. The electronic circuit to monitor the respiratory rate comprises three small circuits: Wien bridge oscillator, voltage to current converter and differential amplifier. This circuit is based on tetra polar impedance technique where current is applied through two pairs of electrode (El and E2) and the potential across another paired of electrodes is measured.</p> |
