MICA: iTraXS (intra Tracheal Multiplexed Sensing): an optical sensor equipped endotracheal tube

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In health, people keep their airway clear by coughing and keeping a resting "tone" in the muscles of the throat and tongue. Seriously ill or anaesthetized patients however cannot do this, so clinicians often use an endotracheal tube (ETT) in the trachea (windpipe) to maintain an open airway. The tube has an inflatable "cuff", which sits inside the trachea and forms a gas-tight seal preventing gas leaks and protecting the lungs from soiling by vomit or blood which can lead to ventilator associated pneumonia. The cellular lining (mucosa) of the trachea is easily injured when pressure from the cuff squeezes oxygen carrying blood out of the tissues. To minimize injury, it is important that this pressure is kept at the minimum necessary to avoid leaks and to protect the lungs from contamination. Unfortunately, clinical staff don't routinely measure pressure, and dangerously high readings are commonplace, resulting in a range of tracheal injuries. Injuries range from moderate to severe sore throat in half of all patients after surgery (500,000 per year in the UK), to lifelong tracheal narrowing (Post Intubation Tracheal Stenosis - PITS) which occurs in around 2000 patients per year in England. Our survey of PITS patients revealed a pattern of delayed diagnosis and significantly reduced physical activity from breathlessness.Our group recently developed a new prototype tube (iTraXS- intra Tracheal Multiplexed Sensing) which uses fine optical fibre sensors in the cuff. In addition to blood flow, oxygenation and temperature measurement, contact pressure with the tracheal wall is measured by the change in wavelength (colour) of light reflected from the sensor. This enables the cuff to be inflated to the most appropriate pressure in order to achieve a gas seal but not to occlude blood flow in the mucosa. This project aims to extend the sensing ability and make clinically compliant versions of our laboratory hardware and software which measure the wavelength changes. We will test the new system in preclinical studies at the University of Nottingham. At the end of this project the device will be ready for clinical trials. We think iTraXS is capable of improving the everyday experience of surgery for patients worldwide and significantly reduce the suffering and costs associated with PITS at low cost to purchasers. In addition, we think that iTraXS will demonstrate the potential of emerging optical sensor technology to enable sensing of the internal environment of patients in real time, providing previously unavailable data to aid clinical decision making. In addition to standard academic dissemination, our partners P3 Medical and Gill Research and Development will provide valuable manufacturing experience and trade exposure. The iTraXS prototype was runner up at the 2018 Innovation Awards of the Association of Anaesthetists of Great Britain and Ireland, which we expect will help us with industry and clinician awareness. Activities conducted in this project such as end user engagement, health economic modelling and market research will help to support the business case.