A study of an intubated tracheal air flow in a cuff-leak testing procedure

During an artificial ventilation, an endotracheal tube (ETT) must be inserted into patient airway and following by a balloon cuff blowing in order to function as an artificial airway. However, this implementation adversely affects to a tracheal tissue and all sensitive area and probably damaging a larynx and vocal cord zone. After ETT was removed, some patients always suffering with a larynx or tracheal edema symptom in which patient airway is narrowed due to a long term pressurization by the ETT balloon cuff and causing a difficulty in his spontaneous breathing. In general, a cuff leak test is performed in order to predict a larynx or tracheal edema possibility before ETT extubation from an air volume difference between an inspiration and expiration. In this paper, an investigation of an airflow pattern and air velocity which able to imply as an air volume in the cuff leak test process is proposed in order to understand and support a prediction of the tracheal edema. The study was performed with no edema and edema case at 10, 30 and 50% of trachea internal diameter. The simulations indicate that airflow pattern shows some affects when edema region is higher than 10%. Even though, this preliminary study was intently implemented in a simple intubated trachea model, however the obtain results guide us a practical information and will be used as a basic implementation for a further study, especially in case of variety in the ETT cuff shape and pressure or in cuff less ventilation even more complication case in the near future.