在出血的人体模型集成的代偿反应
Summary
该协议的目的是证明的技术用于使用下体负压作为可用于定量的人类代偿机制血容量赤字总积分的人类出血的非侵入性的实验模型测量减少中央血容量代偿反应。
Abstract
出血是创伤有关的死亡的首要原因，部分是由于失血的严重性的早期诊断是困难的。出血的患者的评估是困难的，因为目前的临床工具提供的生命体征，由于代偿机制仍然期间出血的早期阶段稳定的措施。因此，有必要了解和测量的该补偿减少循环血液量，以及他们如何持续渐进出血时改变机构的总积分。人体的储备，以弥补减少循环血容量被称为“补偿性储备”。代偿储备可以在动脉波形与使用一个高功率的计算机的测量的特征的变化的实时测量来精确地进行评价。下体负压（LBNP）已经显示出模拟许多生理反应的与出血相关的人类，并且是用来研究对出血的代偿性反应。这项研究的目的是演示过程中中央血量逐步削减与下体负压为出血的模拟储备代偿如何评估。
Introduction
心血管系统的最重要的功能是足够的灌注（血流量和氧输送）到身体的所有组织中，通过动脉血压稳态调节控制。补偿各种机制（ 例如 ，自主神经系统的活动，心率和收缩，静脉回流，血管收缩，呼吸）有助于维持在组织氧气的正常生理水平1的减少在循环血液量例如那些引起出血可以妥协心血管补偿机制的能力，并最终导致低动脉血压，认真组织缺氧，循环性休克，可以是致命的。
严重出血（ 即出血性休克）引起的循环性休克是死亡的主要原因是由于创伤。2一个防止病人从最具挑战性的方面发展的冲击是我们的没有认识到它的早期发病。朝向休克的发展进展的早期和准确的评估目前在临床上由提供在失血因为人体的众多代偿的早期阶段变化很小的生命体征测量技术（ 即，医疗监视器）限定对调节血压的机制。3-6因此，衡量的总和身体的储备，以弥补血液流失的能力代表组织灌注状态的最准确的反映和发展电击的危险。1该储备金被称为。它可以通过改变实时测量动脉波形的特点准确地评估代偿储备代偿储备的枯竭1复制的危重患者低血压突然发作观察到的终端心血管功能不稳定;被称为血液动力学装饰的条件mpensation 7
在人类持续失血期间代偿储备和调节血压的利用之间的关系可以用一套完整的生理测量的实验室证明（ 如血压，心脏率，动脉血氧饱和度，每搏输出量，心输出量，血管阻力，呼吸，脉搏的性格，精神状态，呼气末二氧化碳 ，组织氧）期间，中央血容量相似出血期间发生持续逐步削减通过标准生理监测提供。降低的中心血量可以无创性与下体负压逐步增加（LBNP）诱发。8使用生理测量和下体负压，如何评价人体的补偿减少中央血量可以很容易地能力概念理解的这种组合恶魔trated。该研究描述了实验预习制备，模拟出血期间相对于其他生理反应代偿性反应的示范，和结果的postlab评价。用于做出补偿准备金的测量实验技术证实在人类志愿者。
Protocol
在此之前任何人的过程中，机构审查委员会（IRB）必须批准该协议。在这项研究中使用的协议被批准由美国陆军医学研究和装备司令部IRB。该协议旨在演示在中央血容量逐步减少类似于在受控和可重复的实验室设置持续出血时由个人经历的补偿的生理反应。 25˚C – 实验室房间温度在23控制。 1.设备的准备打开设备并需要预热和校准设备。 注：设备和装置包括一个数据采集系统，?…
Representative Results
该下体负压过程会导致在周围的下部躯干和腿的空气压力降低。作为这种真空逐渐增加，从头部和上部躯干在下体血容量移位来创建中央血容量不足的状态。在中央血容量逐步减少（ 即 ，LBNP）产生与红外线手指光体积描记（ 图5）测量的动脉波形的特征显著改变。该补偿储备指数（CRI）是从采用了独特的机器学习算法，其分析在波形特性的变化来计算…
Discussion
用下体负压引起中央血容量进步和不断的减少，我们能够诱导血液动力学失代偿的主题典型的响应，其特点是低血压和心动过缓（ 图7）突然发作。理解到出血集成代偿反应是非常复杂的是很重要的，19从而在公差失血显著个体变异。1同样地，一些个体具有相对响应的补偿机制，而其他不那样有效地补偿。因此，在该协议中的关键步骤是在实验进行到心血管失代偿的?…
Declarações
The authors have nothing to disclose.
Acknowledgements
这项工作是由美国陆军医学研究和装备司令部，作战伤员救护方案提供资金支持。我们感谢LTC凯文S.埃克斯，MD和克里斯汀R.碱液女士为他们制作的视频帮助。
Materials
| Dynamic Research Evaluation Workstation (DREW) data acquisition syetem | NA | NA | Custom Built by ISR personnel. The DREW allows for time synchronization of both digital and analog signal data collection from up to 16 independent instruments with a sampling rate of 1000 Hz. |
| Finometer | Finapress Medical Systems (FMS) | Model 1 | Device that provides non-invasive, continuous measurements of brachial artery blood pressure and arterial oxygen saturation (SpO2) using two separate infrared finger photophlethymography cuff sensors. |
| BCI Capnocheck Plus | Smith Medical PM Inc. | 9004 | Capnograph used to measure end tidal CO2 and respiration rate |
| CipherOX | Flashback Technologies Inc. | R200 | Investigational device used to calculate Compensatory Reserve Index (CRI) |
| Nonin 9560 Pulse Oximeter | Nonin | 9560 | finger pulse oximeter |
| Lower Body Negative Pressure Chamber (LBNP) | NASA | 79K32632-1 | Custom Chamber built by NASA |
| ECG Biotach | Gould | 13-6615-65 | Electrocardiograph for measuring ECG |
| Nasal CO2 Sample Line | Salter Labs | REF 4000 | Latex free nasal cannula for sampling expired air |
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Citar este artigo
Convertino, V. A., Hinojosa-Laborde, C., Muniz, G. W., Carter, III, R. Integrated Compensatory Responses in a Human Model of Hemorrhage. J. Vis. Exp. (117), e54737, doi:10.3791/54737 (2016).