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

在健康状态下，人们通过咳嗽和在喉咙和舌头的肌肉中保持休息的“音调”来保持呼吸道畅通。然而，重病或麻醉的患者不能做到这一点，因此临床医生经常在气管(气管)中使用气管内管(ETT)来维持开放的呼吸道。该管子有一个可充气的“袖口”，位于气管内，形成一个气密密封，防止气体泄漏，并保护肺部免受呕吐物或血液的污染，后者可能导致呼吸机相关肺炎。当来自袖带的压力挤压组织中携带氧气的血液时，气管的细胞衬里(粘膜)很容易受到损伤。为了最大限度地减少伤害，重要的是将压力保持在必要的最低限度，以避免泄漏和保护肺部免受污染。不幸的是，临床工作人员不经常测量压力，危险的高读数是司空见惯的，导致一系列气管损伤。在所有患者中，有一半的患者术后会出现中度到严重的喉咙痛(在英国，每年有50万人)，在英国，每年约有2000名患者会发生终身气管狭窄(插管后气管狭窄-凹陷)。我们对深陷井患者的调查显示，由于呼吸困难，诊断延迟，体力活动显著减少。我们的团队最近开发了一种新的原型管(iTraXS-Intra True Multiplexed Sensation)，它在袖带中使用了精细的光纤传感器。除了测量血流、氧合和温度外，通过传感器反射的光的波长(颜色)的变化来测量与气管壁的接触压力。这使得袖带可以膨胀到最合适的压力，以实现气体密封，但不会阻塞粘膜中的血液流动。该项目旨在扩展传感能力，并使我们的实验室测量波长变化的硬件和软件符合临床要求。我们将在诺丁汉大学的临床前研究中测试新系统。在这个项目结束时，该设备将准备好进行临床试验。我们认为iTraXS能够改善世界各地患者的日常手术体验，并以较低的成本显著减少与PITS相关的痛苦和成本。此外，我们认为iTraXS将展示新兴光学传感器技术的潜力，能够实时感知患者的内部环境，提供以前无法获得的数据来帮助临床决策。除了标准的学术传播，我们的合作伙伴P3医学和Gill研发将提供宝贵的制造经验和行业曝光率。ITraXS原型在英国和爱尔兰麻醉师协会2018年创新奖上获得亚军，我们预计这将有助于我们提高行业和临床医生的意识。在该项目中开展的活动，如终端用户参与、卫生经济建模和市场研究，将有助于支持业务案例。

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.