抄録
The necessity for world-wide standardization of the method to clinically record lung sounds has been recognized. Previous recording systems using an A-D to D-A converting computer system or copy techinque embloying two to three data recorders had some limitations as follows:
1) The recording length of the waves was too short because of the capacity of the computer memory, 2) Real time recording was impossible. Therefore, these systems were inadequate for analysis and inconvenient for clinical use. Such conditions might well have obstructed the standardization of the method.
According to these considerations, we constructed a new phonopneumograph. We adopted a thermal printer system which had minimal damping for wave recording. Moreover, a recording system of respiratory flow rate or volume using a Fleisch type pneumotachograph was combined with the device.
As a result, real time and non-time-limited recording with simultaneous information on respiratory flow rate or volume has become possible. After several tests, accuracy of waveform recorded was considered highly acceptable even at the maximum speed of 750mm/sec. The device is relatively small and light, and is portable. After actual clinical use, it was suggested that we could easily define rales such as crackles, bubbling or friction rub by analysing the characteristics of waveform and recognition of the respiratory phase where the rales appeared.
