Virginia Commonwealth University Reanimation Engineering Science Center, Virginia Commonwealth University Health System, Richmond, VA, USA.
Resuscitation. 2012 Sep;83(9):1085-9. doi: 10.1016/j.resuscitation.2012.01.033. Epub 2012 Feb 1.
Survival from out-of-hospital cardiac arrest (OOH-CA) remains poor, especially when patients are transported with CPR in progress. Previous investigations suggest that CPR quality erodes during transport due to the austere environment. We sought to determine how frequently ambulance personnel are exposed to off-balancing forces during transport of OOH-CA patients and to estimate the potential impact on CPR and coronary perfusion pressure (CPP).
An onboard monitoring system was utilized to record acceleration data during the transport of 50 OOH-CA patients. Acceleration vectors were calculated for every second of drive time (speed >0 m/s). A model was constructed to estimate the potential impact of these vectors upon CPR and CPP. These data were then compared to a case-control cohort of 102 matched non-urgent transports.
A total of 5.8h of drive time was analyzed in the cardiac arrest cohort. Mean transport time was 8 min 53 s with a mean drive time of 6 min 58 s. Critical acceleration threshold was exceeded 60% of transport time (202.42 min, mean 4.05 min/transport) yielding a potential hands-off ratio of 0.42 with a CPP<15 mmHg 62% of drive time. Ambulance speed was inversely related to the magnitude of off-balancing forces. Comparison to 14.1h of control cohort yielded similar off-balancing forces and relationships despite lower speeds and no "lights and siren" use.
Critical acceleration forces occur frequently during transport of OOH-CA patients and may directly effect CPR quality and thereby CPP. These force vectors are stronger and more frequent at slower speeds, comprising the majority of ambulance drive time. Reducing speed or transporting OOH-CA patients without lights and sirens does little to mitigate these forces.
院外心脏骤停（OOH-CA）患者的存活率仍然很低，尤其是在进行心肺复苏（CPR）的情况下进行转运时。先前的研究表明，由于环境艰苦，CPR 质量在转运过程中会恶化。我们试图确定在转运 OOH-CA 患者时，急救人员经常会受到不平衡力的影响，并估计这对 CPR 和冠状动脉灌注压（CPP）的潜在影响。
使用车载监测系统记录 50 例 OOH-CA 患者转运过程中的加速度数据。为每个驱动时间（速度>0 m/s）的秒计算加速度向量。构建了一个模型来估计这些向量对 CPR 和 CPP 的潜在影响。然后将这些数据与 102 例匹配的非紧急转运的病例对照队列进行比较。
在心脏骤停组中分析了总共 5.8 小时的驱动时间。平均转运时间为 8 分 53 秒，平均驱动时间为 6 分 58 秒。60%的转运时间（202.42 分钟，平均每转运 4.05 分钟）超过了临界加速度阈值，导致潜在的手离比率为 0.42，CPP<15mmHg 的时间占驱动时间的 62%。救护车速度与不平衡力的大小成反比。与对照组的 14.1 小时相比，尽管速度较低且未使用“灯光和警笛”，但仍产生了类似的不平衡力和关系。
在转运 OOH-CA 患者时，经常会产生临界加速度力，并且可能直接影响 CPR 质量，从而影响 CPP。这些力向量在较慢的速度下更强且更频繁，构成了救护车驱动时间的大部分。降低速度或在没有灯光和警笛的情况下转运 OOH-CA 患者几乎无法减轻这些力。
