Kubota Y, Toyoda Y, Ueda Y, Fujimori M, Mori K, Okamoto T, Yasuda T, Matsuura H
Crit Care Med. 1984 Feb;12(2):125-6. doi: 10.1097/00003246-198402000-00010.
The location of a catheter's tip in the bronchi may be determined using a stethoscope and an audible sound that has a frequency of 558 Hz and a sound pressure of 136 dB for the adult. The device is easy and safe to use, and has been used in a broad range of patients for over 4 yr without sequelae.
可使用听诊器以及一种频率为558赫兹、声压为136分贝（针对成年人）的可听声音来确定支气管内导管尖端的位置。该设备使用简便且安全，已在广泛的患者群体中使用了4年多，无后遗症。
