Department of Emergency Medicine, Oregon Health & Science University, Portland, OR 97239, USA.
University of the Basque Country, UPV/EHU, Bilbao, Bizkaia, Spain.
Resuscitation. 2021 Oct;167:180-187. doi: 10.1016/j.resuscitation.2021.08.036. Epub 2021 Aug 27.
Characterize release and recoil dynamics in chest compressions during prolonged cardiopulmonary resuscitation (CPR) efforts, which are increasingly prevalent.
Force and depth of chest compressions, and their rates of change, were calculated from records extracted from CPR monitors used during prolonged resuscitation efforts for out-of-hospital cardiac arrest and tracked over time. Metrics were normalized to the median of the first 100 compressions. Kruskal-Wallis ANOVA and Jonckheere-Terpstra trend analyses were used for differences and trends. Averages are reported as median (interquartile range). Correlations among metrics are reported as coefficients of determination.
In 471 cases of adult subjects receiving at least 1000 compressions, peak depths varied modestly over the course of extended resuscitation efforts, staying within a narrow range without a trend over the course of resuscitation efforts. Increases in recoil velocity and decreases in recoil interval also remained within limited ranges (5%, 6% variation respectively). By contrast, force waveforms changed substantially. Peak force decreased monotonically reaching a 38% decrease for compression numbers > 3500, similar to a decrease in release rate (39%) and an increase in release interval (39%).
Depth waveforms change markedly less than do force waveforms over the course of prolonged CPR. With the benefit of feedback, CPR providers effectively adjust the application of force to compensate for changes in chest stiffness, documented previously. Despite slowing release and quickening recoil, interference between release of force and recoil of depth appears limited. Spontaneous chest recoil is well preserved in prolonged duration manual CPR.
描述在越来越常见的长时间心肺复苏（CPR）努力中，胸部按压的释放和回弹动力学特征。
从用于院外心脏骤停长时间复苏努力的 CPR 监测器中提取记录，并随时间跟踪，计算出胸部按压的力和深度及其变化率。将指标归一化为前 100 次按压的中位数。使用 Kruskal-Wallis ANOVA 和 Jonckheere-Terpstra 趋势分析来比较差异和趋势。平均值以中位数（四分位距）报告。指标之间的相关性以确定系数报告。
在 471 例接受至少 1000 次按压的成年患者中，峰值深度在延长的复苏过程中变化不大，在复苏过程中没有趋势，保持在狭窄范围内。回弹速度的增加和回弹间隔的减少也在有限的范围内（分别为 5%和 6%的变化）。相比之下，力波形发生了很大的变化。峰值力呈单调下降趋势，按压次数超过 3500 次时下降 38%，与释放率（39%）下降和释放间隔（39%）增加相似。
在长时间 CPR 过程中，深度波形的变化明显小于力波形。在反馈的帮助下，CPR 提供者有效地调整力的应用，以补偿先前记录的胸部刚度变化。尽管释放速度减慢，回弹速度加快，但力的释放和深度的回弹之间的干扰似乎有限。在长时间手动 CPR 中，自发性胸廓回弹得到很好的保持。
