Flow sensing for an artificial pancreas

描述(申请人提供)：糖尿病治疗的长期目标是创造一种“人工胰腺”，以取代生物胰腺在患者中的作用。这种人工胰腺必须不断地测量血糖，并使用适当剂量的胰岛素和/或胰高血糖素来响应，以实现人工模拟的稳态。然而，人工胰腺受到生物系统中没有经历过的限制，已知的是，由于磁场的存在、管道中的闭塞和断开，甚至在高海拔地区旅行，泵输送的胰岛素不准确。因此，患者在或人工胰腺系统意识到问题之前，可能会经历几个小时的血糖水平失控，这会导致临床结果恶化。胰岛素泵容易出现这样的误差，因为它们有一个简单但重要的限制--它们不能直接测量液体的流速。如今，泵通过测量泵内部的过程来估计其输送速度，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。然而，这些间接传感器不能检测到环境中所有可能的变化，因此暂时失去了闭环控制。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，可以1%的精度记录流量，并提供即时检测输液错误，如堵塞的增长。我们研究的长期目标是证明我们的流量测量技术对非卧床胰岛素输送的适用性，以便泵制造商可以将其整合到人工胰腺系统中。在这项拟议工作的第一阶段，我们将展示我们的流量传感器在胰岛素输送中的适用性。针对非卧式胰岛素泵的独特流动特性，我们将使用多物理建模来优化我们设备的设计，以便单芯片可以准确测量给药过程中的低基础流速和高流速。我们将进一步优化设计，将功耗降至最低，以展示传感器与可移动人工胰腺的便携式电池要求的兼容性。最后，我们将演示成功的设计阶段，方法是在实验室以团注模式测量现成的非卧式泵在三天内的基础状态下产生的流量，并演示对人工产生的堵塞的快速反应。第一阶段计划将最终设计一种便携式传感器单元，我们将在第二阶段建造和测试。

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.