Department of Systems and Computer Engineering, Carleton University, Ottawa, Canada.
Department of Biology, Carleton University, Ottawa, Canada.
Sci Rep. 2021 Aug 12;11(1):15166. doi: 10.1038/s41598-021-94157-w.
Restraint asphyxia has been proposed as a mechanism for some arrest-related deaths that occur during or shortly after a suspect is taken into custody. Our analysis of the literature found that prone positioning, weight applied to the back, recovery after simulated pursuit, and restraint position have led to restrictive, but non life-threatening respiratory changes when tested in subsets. However, the combined effects of all four parameters have not been tested together in a single study. We hypothesized that a complete protocol with high-sensitivity instrumentation could improve our understanding of breathing physiology during weighted restraint. We designed an electrical impedance tomography (EIT)-based protocol for this purpose and measured the 3D distribution of ventilation within the thorax. Here, we present the results from a study on 17 human subjects that revealed FRC declines during weighted restrained recovery from exercise for subjects in the restraint postures, but not the control posture. These prolonged FRC declines were consistent with abdominal muscle recruitment to assist the inspiratory muscles, suggesting that subjects in restraint postures have increased work of breathing compared to controls. Upon removal of the weighted load, lung reserve volumes gradually increased for the hands-behind-the-head restraint posture but continued to decrease for subjects in the hands-behind-the-back restraint posture. We discuss the possible role this increased work of breathing may play in restraint asphyxia.
束缚性窒息已被提出作为某些与逮捕相关的死亡事件的发生机制，这些事件发生在嫌疑人被拘留期间或之后不久。我们对文献的分析发现，在亚组测试中，俯卧位、背部施压、模拟追捕后的恢复以及束缚位置导致了限制但非危及生命的呼吸变化。然而，这四个参数的综合影响尚未在单一研究中进行测试。我们假设一个具有高灵敏度仪器的完整方案可以提高我们对束缚状态下呼吸生理的理解。为此，我们设计了一个基于电阻抗断层成像（EIT）的方案，并测量了胸部内部的通气三维分布。在这里，我们介绍了一项对 17 名人类受试者的研究结果，该研究表明，在从运动中恢复时，对于处于束缚姿势的受试者，而不是控制姿势的受试者，加权束缚后 FRC 会下降。这些 FRC 的持续下降与腹部肌肉募集以辅助吸气肌肉一致，这表明与对照组相比，处于束缚姿势的受试者呼吸做功增加。当去除加权负荷时，头后双手束缚姿势的肺储备量逐渐增加，但对于头后双手束缚姿势的受试者，肺储备量继续减少。我们讨论了这种增加的呼吸功在束缚性窒息中可能起的作用。
