Microwave sterilization of hemodialysis catheter systems

描述（由申请人提供）：终末期肾病（ESRD）患者接受血液透析的生存率在很大程度上取决于血管通路的维持。然而，导管相关的血流感染仍然是血液透析患者败血症和重复住院的最重要原因之一。虽然遵守严格的无菌技术和使用化学防腐剂消毒导管接头是血液透析单位的公认做法，但这些方法并未显著降低临床感染率。抗生素封管技术的使用已经导致导管相关感染的适度减少，然而这种做法也被认为会加速抗生素耐药物种的生长。为了满足这一临床需求，Med-Conduit，Inc开发了一种微波灭菌器械，能够对盐水填充的连接器施加湿热。目前的第一阶段研究将集中在体外实验台模型的发展，以表征这种微波能量对有限体积液体中存在的细菌种群的杀伤力。我们的长期目标将是产生一种系统，该系统表现出快速和节能的减少用于将中心静脉导管连接到血液透析仪器的连接器中的细菌菌落形成和生物膜沉积。我们的项目将被设计为优化基础射频信号的功率和频率，信号接收天线的形状，目标体积的位置和方向，以及波导结构的形状和拓扑结构，以改善目标体积中的热传递和消毒，从而优化消毒的速率和功效。为了实现这一目标，我们提出了以下具体目标：目标1：完成用于血液透析的微波消毒系统的设计。目的2：在系统模拟的基础上，制作并评价一种消毒系统的加热能力。目的3：评估原型系统在细菌菌落减少方面的性能。如果第一阶段研究成功，我们将在第二阶段提出设计，制造和测试最终设备，以满足临床环境的尺寸，重量和性能的实际需求。 公共卫生相关性：导管相关菌血症（CRB）是接受长期血液透析的终末期肾病（ESRD）患者住院的最常见原因，占疾病管理成本的近三分之一，死亡率为12- 25.9%。血液透析在为ESRD患者提供生命支持方面的成功仍然与限制入路导管细菌定植从而降低CRB发生率的能力密不可分。目前的临床实践，包括使用严格的无菌技术和各种抗生素输送系统，尚未成功地改善这一问题。Med-Conduit开发了一种微波技术，可促进导管与体外回路接口处的液体快速加热，从而促进消毒。本I期研究的目标是设计、制造和测试一种新型微波系统，以在血液透析系统的导管接口处提供消毒。如果第一阶段研究成功，将在第二阶段提出，以创建一个最终的设备，满足实际需求的大小，重量和性能的临床设置。

DESCRIPTION (provided by applicant): The survival of patients with end-stage renal disease (ESRD) on hemodialysis is largely dependent upon the maintenance of vascular access. Yet catheter related blood stream infection remains one of the most important causes of sepsis and repeat hospital admissions among hemodialysis patients. While observance of strict sterile technique and the use of chemical antiseptics to disinfect catheter connectors is accepted practice in hemodialysis units, these methods have not significantly reduced clinical infection rate. The use of antibiotic lock techniques has resulted in a modest reduction of catheter related infections, yet this practice is also known to accelerate the growth of antibiotic resistant specie. To address this clinical need, Med-Conduit, Inc has developed a microwave sterilization device that enables the application of moist heat to saline filled connectors. The current Phase I research will be focused on the development of an in-vitro bench model to characterize the lethality of such microwave energy on bacteria populations present in finite volumes of liquid. Our long term goal will be to generate a system that exhibits rapid and energy efficient reduction of bacterial colony formation and biofilm deposition in the connectors used to attach a central venous catheter to a hemodialysis instrument. Our project will be designed to optimize the power and frequency of the underlying radio frequency signals, the shape of the signal-receiving antenna, the location and orientation of the target volume, and the shape and topology of the wave-guide structure in a manner that improves heat transfer and disinfection in the target volume and thus optimizes the rate and efficacy of disinfection. To address this goal, we propose the following Specific Aims: Aim 1: To complete the design of a microwave-based disinfection system for use in hemodialysis. Aim 2: Based on the system simulation, to fabricate and evaluate the heating capacity of a prototype disinfection system. Aim 3: To assess performance of prototype systems in terms of bacterial colony reduction. If this Phase I research is successful, we will propose in Phase II to design, fabricate and test a finalized device that meeting the practical demands of size, weight, and performance of the clinical setting. PUBLIC HEALTH RELEVANCE: Catheter related bacteremia (CRB) comprises the most common reason for hospitalization for patients with end-stage renal disease (ESRD) undergoing chronic hemodialysis, accounts for nearly one third of the cost of disease management, and is associated with a mortality of 12-25.9%. The success of hemodialysis in provide life support to patients with ESRD remains inextricably linked to the ability to limit bacterial colonization of th access catheters and thereby to reduce the incidence of CRB. Current clinical practice, including the use strict sterile technique and various antibiotic delivery systems, has not been successful in ameliorating this problem. Med-Conduit has developed a microwave technology which promotes rapid heating of fluids at the catheter interface with the extracorporeal circuit, and thus promotes disinfection. The goal of this Phase I research will be to design, fabricate and test a novel microwave system to provide disinfection at the catheter interface with the hemodialysis system. If this Phase I research is successful, will be propose in Phase II to create a finalized device that meets the practical demands of size, weight and performance of the clinical setting.