Development of an optic fibre sensor equipped endotracheal tube

Background Endotracheal tube cuff related injury has been widely described and extensively studied. The endotracheal tube has evolved over time with various modifications. We have developed an endotracheal tube with optic fibre sensors which we believe could provide a solution to the problem of endotracheal cuff related injury. Objectives Can the novel sensor equipped endotracheal tube provide a measurement of contact pressure between the cuff and tracheal mucosa? Can it measure mucosal blood flow? Methods The study was carried out in adolescent pigs. The animals were anaesthetised using a standardised regime and intubated with the novel endotracheal tubes. Contact pressure and mucosal blood flow was collected as per our protocol. The trachea was removed en-bloc and histological analysis was provided by two pathologists who had been blinded to the study protocol. We collected two further tracheal samples, one from an animal intubated using a conventional red rubber endotracheal tube and another from an unintubated animal. Results 6 animals were studied in total. We were able to collect contact pressure and mucosal blood flow data for five of these animals. There was one technical failure which has been addressed subsequently. Histological specimens from the animals intubated using our modified tube and the conventional tube demonstrated an acute suppurative tracheitis. We found the existing scoring systems of tracheal injury inadequate for our needs and developed a more detailed scoring system. Conclusions In this small study of an optic fibre equipped endotracheal tube, we were able to demonstrate function of the optical fibres in terms of providing us the ability to measure contact pressure as well as mucosal blood flow. The cause of the failure was investigated and has been addressed. We were also able to develop a new, detailed scoring system which will be of use in future studies.