Respiratory resistance of tracheostomy tubes

One of the main results of tracheostomy is to reduce the airflow resistance and power of breathing. The airflow dynamics of three types of commonly used tracheostomy tubes were studied. A generator was used to produce a sinusoidal airflow wave to simulate normal breathing. The flow resistance and the power required to overcome this resistance were measured. A difference was observed in the flow resistance and the power of breathing between the inspiratory and expiratory phase of all the tubes. It was also observed that the Portex and Jackson tubes have a lower flow resistance and power of breathing than the similar gauge Shiley tube. This difference was due to the greater length, shorter radius of curvature, and rougher inner surface of the Shiley tube.