Impedance Threshold Value for Improving Standard CPR

描述(由申请人提供)： 尽管基本和高级生命支持的做法很普遍，但在美国，每天有1000多名患者死于院外心脏骤停。即使他们接受了标准的心肺复苏(SCPR)，这些患者到出院的平均全国存活率不到5%。申请人开发了吸气阻抗阈值装置(ITD)，在SCPR的减压阶段增加胸腔内负压，从而使前向血流加倍。第二阶段临床试验表明，初始心律为无脉搏电活动的患者的重症监护病房入院率(主要研究终点)从19%增加到52%(p=0.02)。在第二阶段，研究人员还发现了心肺复苏期间血液流动的一个基本新原理：胸腔内压和冠脉灌注压以及脑灌注压和存活率之间存在负相关关系。随着胸腔内压力的增加，冠状动脉和脑灌注压以及存活率下降。第二阶段的研究进一步发现，在SCPR期间，通气率和持续时间往往过高，而且每次按压后胸部往往不能完全后退。这些常见的临床错误都是第一次被电子记录下来，然后在心脏骤停的动物模型中被证明是有害的，如果不是致命的话。基于这些第二阶段的结果，申请者改进了ITD，增加了一个通风计时灯来引导适当的通风，并为SCPR开发了一个新的和改进的手部姿势，以帮助促进完全胸壁后坐。另一种确保在每次胸部按压后出现至关重要的完全胸部后坐的方法是使用主动按压减压(ACD)CPR，这也是申请者利用手持设备开发的一种技术。基于这些第二阶段的结果，将进行第二阶段的持续研究，以获得足够的临床数据，为ITD作为一种旨在提高心脏骤停后24小时存活率的技术获得监管批准。一项关键的临床试验以前瞻性、随机、双部位临床试验的形式被提出：1)确定使用改进的SCPR的ITD时的24小时存活率；2)确定使用ITD时的24小时存活率，并确保ACD CPR的完全胸壁后坐。仅在美国就有40万人死于心脏骤停，这项技术的广泛应用每年可能会导致5万人额外存活。

DESCRIPTION (provided by applicant): Despite the widespread practice of basic and advanced life support, over 1000 patients die each day in the United States from an out-of-hospital cardiac arrest. Even though they receive standard cardiopulmonary resuscitation (sCPR) the average national survival to hospital discharge for these patients is less than 5%. The applicants have developed the inspiratory impedance threshold device (ITD) to increase negative intrathoracic pressure during the decompression phase of sCPR, thereby doubling forward blood flow. The Phase 2 clinical trial demonstrated that intensive care unit admission rate (primary study endpoint) in patients with an initial heart rhythm of pulseless electrical activity increased from 19% to 52% (p=0.02). During Phase 2 investigators also discovered a fundamental new principle of blood flow during CPR: an inverse relationship between intrathoracic pressure and coronary perfusion pressure as well as cerebral perfusion pressure and survival rates. With increased intrathoracic pressure, coronary and cerebral perfusion pressures, as well as survival rates, decreased. The Phase 2 research further lead to the discovery that during sCPR ventilation rates and duration are often excessive and that the chest is often not allowed to fully recoil after each compression. Each of these common clinical errors was electronically recorded for the first time and then shown to be detrimental, if not deadly, in animal models of cardiac arrest. Based upon these Phase II results the applicants have improved the ITD by adding a ventilation timing light to guide proper ventilation and developed a new and improved hand position for sCPR to help promote full chest wall recoil. Another way to assure that the critically important full chest recoil occurs after each chest compression is by using active compression decompression (ACD) CPR, a technique also developed by the applicants that utilizes a hand held device. Based upon these Phase 2 results, the Phase 2 continuation research will be conducted to obtain sufficient clinical data for regulatory clearance for the ITD as a technology intended to improve 24-hour survival rates after cardiac arrest. A pivotal clinical trial is proposed in the form of a prospective, randomized, two-site clinical trial to: 1) determine the 24-hour survival rate when using the ITD with improved sCPR, and 2) to determine the 24-hour survival rate when using the ITD and assuring full chest wall recoil with ACD CPR. With 400,000 out-of-hospital deaths from cardiac arrest in the United States alone, widespread application of this technology could result in 50,000 additional survivors per year.