Flow sensing for an artificial pancreas

描述（由申请人提供）：糖尿病治疗的长期目标是创造一种“人工胰腺”，以替代患者生物胰腺的作用。这种人工胰腺必须不断测量葡萄糖，并以适当剂量的胰岛素和/或胰高血糖素作出反应，以实现体内平衡的人工模拟。然而，人工胰腺受到生物系统中没有经历过的限制，并且已知通过泵输送胰岛素由于诸如磁场的存在、线路中的闭塞和断开以及甚至在高海拔处行进的因素而变得不准确。因此，患者可能会在他们或人工胰腺系统意识到问题之前经历失控的葡萄糖水平数小时，这导致临床结果下降。胰岛素泵由于一个简单但重要的限制而受到这种误差的影响-它们不能直接测量流体流速。今天的泵通过测量泵内部的过程来估计其输送速率，例如齿轮转动了多少次，并增加了单独的传感器来处理许多可能的故障中的每一个。然而，这些间接传感器不能检测环境中所有可能的变化，因此暂时失去闭环控制。Fluonic开发了一种简单的一次性流量传感器，可以直接集成在患者的注射点，并且可以以1%的准确度记录流速，并提供对输液错误（如阻塞增长）的即时检测。我们研究的长期目标是证明我们的流量测量技术对动态胰岛素输送的适用性，以便泵制造商可以将其纳入人工胰腺系统。在本研究的第一阶段，我们将证明我们的流量传感器用于胰岛素输送的适用性。我们将使用多物理场建模来优化我们的设备的设计，以适应非卧床胰岛素泵的独特流量特性，从而使单个芯片可以准确测量低基础流量和大剂量给药期间的较高流量。我们将进一步优化设计，以最大限度地降低功耗，以证明传感器与便携式人工胰腺电池要求的兼容性。最后，我们将通过在实验室中测量三天内基础和推注模式下现成的流动泵产生的流量，并证明对人工产生的阻塞的快速反应，来证明成功的设计阶段。第一阶段计划将最终设计一个便携式传感器单元，我们将在第二阶段建立和测试。

DESCRIPTION (provided by applicant): The long term objective of diabetes treatment is to create an "artificial pancreas" to substitute for the role of the biological pancreas in patients. This artificial pancreas must constantly measure glucose and respond with an appropriate dose of insulin and/or glucagon to achieve an artificial analog to homeostasis. However, the artificial pancreas is subject to limitations not experienced in biological systems, and delivery of insulin by pumps has been known to be made inaccurate by factors such as the presence of magnetic fields, occlusions and disconnects in the lines, and even travel at high altitudes. As a result, patients can experience out-of-control glucose levels for hours before they or the artificial pancreas system becomes aware of a problem, and this results in degraded clinical outcomes. Insulin pumps are subject to such errors because of a simple but significant limitation - they cannot directly measure the rate of fluid flow. Pumps today estimate their rate of delivery by measuring processes internal to the pump, such as how many times a gear has turned, with the addition of separate sensors to deal with each of many possible faults. These indirect sensors cannot detect all possible variations in environment, however, and as a result closed loop control is temporarily lost. Fluonic has developed a simple, disposable flow sensor that can be integrated directly at the injection point at the patient, and which can record flow rates with 1% accuracy and provide immediate detection of infusion errors such as the growth of an occlusion. The long term goal of our study is to demonstrate the applicability of our flow measurement technology to ambulatory insulin delivery, so that it can be incorporated into artificial pancreas systems by pump manufacturers. In Phase I of this proposed work, we will demonstrate the applicability of our flow sensor for use in insulin delivery. We will use multiphysics modeling to optimize the design of our devices for the unique flow characteristics of ambulatory insulin pumps, so that a single chip can accurately measure both low basal flow rates and the higher flow rates seen during bolus administration. We will further optimize the design to minimize power consumption, in order to demonstrate compatibility of the sensor with the portable battery requirements of an ambulatory artificial pancreas. Finally, we will demonstrate the successful design phase by measuring flow created by an off-the-shelf ambulatory pump in both basal in bolus mode in the laboratory over a three day period, and demonstrating rapid response to the presence of an artificially-produced occlusion. The Phase I program will culminate in a design for a portable sensor unit, which we will build and test in Phase II.