[Diagnosis of inhalation injury by larynx-tracheal respiratory sound].

The experiment in rabbits demonstrated that the more narrow the tracheas were, the higher the frequency of respiratory sound was. The frequency of tracheal respiratory sound was about 50-100 Hz in normal rabbits. In mildly narrow frequency of respiratory sound was 50-200 Hz, in mediately narrow trachea 200-300Hz, in severely narrow trachea 400-700 Hz. 74 patients were studied. The patients with more severe inhalation injury had higher tone of respiratory sound and simultaneously showed dyspnea because their larynx-tracheas became more narrow due to edema. When high tone appeared obviously tracheostomy must be immediately performed to release obstruction of the respiratory tract. 26 of these patients underwent tracheostomy. This reliable, simple diagnosis can be used to monitor larynx-tracheal condition, and high tone of respiratory sound can be used as an indication for tracheostomy.