Design and Development of a Tracheostomy Tube Test Device

In the NRC (National Respiratory Centre) department at Danderyds Hospital different standard tracheostomy tubes are customized in order to create a more appropriate fit for the individual patient. This master thesis aims to design a theoretical model and build a first prototype of a tracheostomy tube test device that can be used to analyse and compare the physiological performance of different for tracheostomy tubes. The theoretical model of the device consisted of an artificial lung, artificial trachea and a ventilator, pressure and flow sensors and a data acquisition device. The first prototype was built using equipment available at the NRC department and three experimental set-ups were assembled: one simulating normal breathing and two set-ups simulating coughing. Two artificial tracheas, a small and a large one together with different tracheostomy tubes were used to evaluate the first prototype. Results showed that the first prototype could be used to compare cuffed fenestrated and non-fenestrated tracheostomy tubes. However, the first prototype was less effective when comparing uncuffed fenestrated and non-fenestrated tracheostomy tubes, which is due to the lack of airway resistance in uncuffed tubes. Results strongly motivate a further development of the device with equipment described in the theoretical model and the future studies should be focused on improving the device.