A Simple and Sensitive Airflow Sensor for Sleep Studies

睡眠障碍影响着4000多万美国人。白天过度嗜睡是一个主要的健康问题，导致交通事故死亡人数增加，并降低了工作效率。多导睡眠图（PSG）是诊断睡眠障碍的唯一有效方法。PSG依赖于许多生理参数的准确检测。其中一个重要的监测参数是气流。目前，气流是通过使用热敏电阻感应呼吸过程中的温度波动来间接测量的。许多研究表明，感知压力比感知温度更敏感；它揭示了热敏电阻经常错过的微妙但重要的临床信号。研究还表明，基于压力的气流与实际气流相关联，提供了更好的定量测量。然而，到目前为止，目前基于压力的设备使用鼻套管来读取压力。鼻插管体积庞大，对患者的侵入性更强，容易凝结，并可能产生伪影。此外，鼻插管在每次使用的基础上更昂贵。我们建议开发一种新颖而简单的基于压力的气流传感器，该传感器将用尖端集成有敏感微机械（MEMS）压力传感器的电缆取代套管。传感器元件将靠近患者，这将允许更好的信号检测。灵敏度的提高也将消除对尖头的需要，使该设备比插管系统侵入性更小。该设备将有多个传感器，分别提供鼻腔和口腔气流信号。我们将利用已经为许多应用建立的具有成本效益和高灵敏度的MEMS解决方案来生产廉价且快速上市的产品。在第一阶段，我们将使用现有的传感器构建原型，并在实验台上和志愿者身上进行评估。在第二阶段，将开发和测试传感器和相关电子设备的最终包装，并获得监管部门的批准。建议的商业应用：简要概述该研究的潜在商业应用。我们估计这种设备在美国现有的市场规模为每年15000个传感器。这个市场有巨大的增长潜力。在估计的1200万阻塞性睡眠呼吸暂停患者中，只有100万患者被诊断出来。这使得大量人口需要PSG，因此对PSG配件（如拟议的设备）产生了巨大的潜在需求。由于对其影响的高度重视，其他睡眠领域也在增长。总体而言，睡眠设备市场预计将以17%的速度增长。

Sleep disorders affect more than 40 million Americans. Excessive daytime sleepiness is a major health problem contributing to the increasing vehicular fatalities, and reduced work productivity. A polysomnograph (PSG) is the only effective way to diagnose sleep disorders. PSG relies on accurate detection of many physiological parameters. One of the important parameters to monitor is airflow. Currently, airflow is measured indirectly by sensing temperature fluctuations during breathing using thermistors. Many studies showed that sensing pressure, instead of temperature, is more sensitive; it reveals subtle but important clinical signals often missed by thermistors. Studies also showed that pressure-based airflow is correlated to actual airflow offering a better quantitative measure. So far, however, current pressure- based devices use nasal cannula for pressure reading. Nasal cannula are bulky, more intrusive to the patient, susceptible to condensation and can generate artifacts. Also, nasal cannula are more expensive on per use basis. We propose to develop a novel and simple pressure-based airflow sensor that will replace the cannula with a cable having sensitive micromachined (MEMS) pressure sensors integrated at the tip. The sensor elements will be proximal to the patient, which will allow better signal detection. Improved sensitivity will also eliminate the need for prongs making the device less intrusive than cannulae systems. The device will have multiple sensors offering separate nasal and oral airflow signals. We will capitalize on cost efficient and highly sensitive MEMS solutions already established for many applications to produce inexpensive and fast to market product. In Phase I, we will construct prototypes using existing sensors and evaluate them on the bench and on volunteers. In Phase II, final packaging of the sensor and associated electronics will be developed and tested, and regulatory approval obtained. PROPOSED COMMERCIAL APPLICATIONS: Provide a brief summary of the potential commercial applications of the research. We estimate the existing U.S. market size for this device at 15,000 sensors per year. The market has a huge growth potential. Out of the estimated 12 million people who suffer from OSA only 1 million patients are diagnosed. This leaves a large population in need of PSG and therefore creates a large potential demand for PSG accessories such as the proposed device. Other sleep segments are also witnessing growth due to the heightened appreciation of its implications. Overall, the sleep devices market is expected to grow at 17%.