Optical Detection of Exhaled Intravenous Anaesthetics

在这个提议中，我们回应了对手术期间患者血液中麻醉剂浓度的临床在线监测的真实的和迫切的需求。尽管常规临床使用静脉麻醉剂，但不存在用于在线监测其血浆浓度的可行传感器。该项目的重点是开发下一代丙泊酚传感技术，丙泊酚被广泛用作手术期间的麻醉药和重症监护室重症患者的镇静剂。异丙酚对心血管系统有深远的影响，降低血压、心输出量和重要器官（如大脑和肾脏）的灌注。因此，不正确使用丙泊酚的后果是严重的。目前，丙泊酚诱导麻醉的有效性仅通过解剖学评估。一个可行的在线监测丙泊酚呼出水平的能力将大大提高对其管理的控制水平。它既可以通过根据个人需要调整剂量来提高麻醉管理的质量，又可以减少临床恢复时间和患者的善后护理，并具有相关的成本效益。我们建议通过光学测量患者呼出气中丙泊酚的浓度来研究临床在线监测患者血液中丙泊酚浓度的可行性。最近的医学研究表明，在手术过程中，患者呼出气中存在的丙泊酚混合比例按体积计为十亿分之几。该应用程序是雄心勃勃的，高影响力的，并且非常热门，推动了该领域的前沿。呼气丙泊酚浓度的可行光学感测策略的挑战是普遍存在的低浓度;丙泊酚的差的光谱表征;产生竞争信号的污染物种类的存在;以及重要的是，需要有机会在临床环境中部署的稳健、快速和经济的系统。目前还没有任何技术可以满足所有这些需求。在这个项目中，我们提出了两个国家的最先进的光学检测技术，有可能满足要求。我们建议进行系统的研究，在线监测呼出异丙酚的可行性，首先，定量的吸收截面的异丙酚，其次，确定可达到的检测限，使用选定的候选技术，第三，研究的影响，光谱干扰所造成的其他气体存在于呼出气。该项目是一项开创性的活动，是基于一个独特的多学科专业人士的合奏，专注于高影响力的研究挑战。高影响力的应用程序已建立在咨询与医疗麻醉专业人员，教授T。Absalom和Dr. D.惠勒，麻醉科，临床医学院，剑桥大学。只有这种合作才能提供临床样本采集和制备所需的专业知识和最先进的知识。研究人员在新型光学传感器开发方面的专业知识以出色的方式满足了项目要求。如果成功的话，这项研究可能会导致麻醉师在手术室中进行手术的方式发生范式转变。

In this proposal we respond to a real and acute need for clinical online monitoring of anaesthetic concentrations in patients' blood during surgery. Despite of the routine clinical use of intravenous anaesthetics no viable sensors for online monitoring of their blood plasma concentration exist. The project focuses on the development of next generation sensing technology for propofol, which is used widely as an anaesthetic drug during surgery and as a sedative in critically ill patients on intensive care units. Propofol exerts profound effects on the cardiovascular system, reducing blood pressure, cardiac output, and the perfusion of vital organs such as the brain and kidneys. The consequences of incorrect administering of propofol are therefore grave. Currently the effectiveness of propofol induced anaesthesia is only assessed symptomatically. A viable online capability to monitor exhaled levels of propofol would dramatically improve the level of control over its administration. It would both improve the quality of anaesthetic management by tailoring dosage to individuals' needs and reduce clinical recovery times and patient aftercare with associated cost benefits. We propose to study the feasibility of clinical online monitoring of propofol in patient's blood by optically measuring the concentration of propofol in the patient's exhaled breath. Recent medical studies have shown that mixing ratios of propofol at a level of parts per billion by volume exist in the patients' exhaled breath during surgery. The application is ambitious, high impact, and very topical pushing the frontiers of the field. Challenges for viable optical sensing strategies of exhaled propofol concentration are the low concentrations prevailing; the poor spectroscopic characterization of propofol; the presence of contaminant species that create competitive signals; and, importantly, the requirement for a robust, fast and economical system that stands a chance to be deployed in a clinical context. Currently there are no available technologies that meet all these demands. In this project we propose two state of the art optical detection techniques that have the potential to meet the requirements. We propose to conduct a systematic study on the feasibility of online monitoring of exhaled propofol by, first, quantifying the absorption cross sections of propofol, secondly, determining the attainable detection limits using the selected candidate technologies and, thirdly, studying the effects of spectral intereference caused by the other gases present in the exhaled breath. The project is a pioneering activity and is based on a unique multidisciplinary ensemble of professionals focusing on a high impact research challenge. The high impact application has been established in consultation with medical anaesthesia professionals, Prof. T. Absalom and Dr. D. Wheeler, Division of Anaesthesia, School of Clinical Medicine, University of Cambridge. Only this collaboration can provide the needed expertise and state of the art knowledge on the clinical sample collection and preparation. The Researcher's expertise in the development of novel optical sensors matches the project requirements in an excellent fashion. If successful, this research could lead to a paradigm shift in the way anesthetists are able to operate in the operating theatre.