Applied Physics Laboratory, University of Washington, Seattle, WA, United States.
Department of Emergency Medicine, University of Pittsburgh, Pittsburgh, PA, United States.
Resuscitation. 2019 Jan;134:76-80. doi: 10.1016/j.resuscitation.2018.10.021. Epub 2018 Oct 23.
Hemodynamic-guided cardiopulmonary resuscitation (HGCPR) achieves better outcomes than standard resuscitation. Currently, HGCPR requires an invasive procedure, infeasible during resuscitation. Non-invasive measures of blood flow could provide useful hemodynamic guidance to rescuers.
We describe initial efforts to develop a device that detects, analyzes, and measures the velocity of carotid artery blood flow (CABF) towards the brain at pre-arrest baseline ('baseline') and during cardiopulmonary resuscitation, here tested in a swine model of cardiac arrest (CA). A key element of that device consists of non-imaging diagnostic ultrasound, due to its simplicity and small form factor, hence potential for deployment during HGCPR in a bandage placed on the neck.
Sixteen mixed-breed domestic swine were sedated, anesthetized and paralyzed, followed by endotracheal intubation and mechanical ventilation. Cardiac arrest was induced with a 3-s 100 mA transthoracic shock or bolus of fentanyl, after which all animals received mechanical CPR. A non-imaging ultrasound probe was manually applied to the neck over the carotid artery to capture CABF during baseline, as verified with diagnostic ultrasound imaging, and during mechanical resuscitation.
We successfully collected CABF measurements at baseline in 14/16 swine and during attempted resuscitation with mechanical chest compression in 5/16 swine. Signal characteristics include peak blood flow both towards (90.4 +/-20.4 cm/s) and away from the brain (-44.2 +/-31.8 cm/s) during resuscitation, each larger than flow towards (41.7+/-14.8 cm/s) and away from brain (-3.0 +/-7.8 cm/s) during baseline.
Measurement of CABF before and during CPR in swine with a non-imaging ultrasound probe is feasible before CA and informative when achieved during CPR. For example, observations of reverse flow within the carotid artery during CPR merits further study for its prevalence and effect on resuscitation outcomes. Also, tissue motion represents a significant obstacle for CABF measurement during CPR. Additional work will determine the feasibility and utility of non-imaging ultrasound measurements of CABF during resuscitation.
血流动力学指导的心肺复苏（HGCPR）比标准复苏效果更好。目前，HGCPR 需要进行有创操作，在复苏过程中不可行。非侵入性血流测量方法可以为抢救者提供有用的血流动力学指导。
我们描述了开发一种设备的初步努力，该设备可以检测、分析和测量颈动脉血流速度（CABF）向大脑的方向，在心脏骤停前的基线（“基线”）和心肺复苏期间进行测量，在此通过猪心脏骤停（CA）模型进行测试。该设备的一个关键要素是使用非成像诊断超声，由于其简单性和小尺寸，因此有可能在 HGCPR 期间在颈部绷带中部署。
16 只杂种家猪被镇静、麻醉和麻痹，然后进行气管插管和机械通气。用 3 秒 100 mA 经胸电击或芬太尼冲击诱导心脏骤停，然后所有动物均接受机械心肺复苏。手动将非成像超声探头应用于颈部颈动脉上方，以在基线期间捕获 CABF，并用诊断超声成像进行验证，并在机械复苏期间捕获 CABF。
我们成功地在 16 只猪中的 14 只收集了基线时的 CABF 测量值，在 5 只猪中的 16 只尝试进行机械胸部按压时收集了 CABF 测量值。信号特征包括复苏期间向大脑方向（90.4+/-20.4 cm/s）和远离大脑方向（-44.2+/-31.8 cm/s）的峰值血流，均大于基线时向大脑方向（41.7+/-14.8 cm/s）和远离大脑方向（-3.0+/-7.8 cm/s）的血流。
使用非成像超声探头在 CA 前和 CPR 期间对猪进行 CABF 测量是可行的，并且在 CPR 期间进行测量时具有信息性。例如，在 CPR 期间观察到颈动脉内反向血流值得进一步研究其普遍性及其对复苏结果的影响。此外，组织运动是 CPR 期间 CABF 测量的一个重大障碍。进一步的工作将确定在复苏期间使用非成像超声测量 CABF 的可行性和实用性。
