Latimer Andrew J, Counts Catherine R, Van Dyke Molly, Bulger Natalie, Maynard Charles, Rea Thomas D, Kudenchuk Peter J, Utarnachitt Richard B, Blackwood Jennifer, Poel Amy J, Arbabi Saman, Sayre Michael R
Department of Emergency Medicine, University of Washington, Seattle, Washington.
Department of Health Systems and Population Health, University of Washington, Seattle, Washington.
Shock. 2023 Oct 1;60(4):496-502. doi: 10.1097/SHK.0000000000002188. Epub 2023 Aug 7.
Background: The compensatory reserve index (CRI) is a noninvasive, continuous measure designed to detect intravascular volume loss. CRI is derived from the pulse oximetry waveform and reflects the proportion of physiologic reserve remaining before clinical hemodynamic decompensation. Methods: In this prospective, observational, prehospital cohort study, we measured CRI in injured patients transported by emergency medical services (EMS) to a single Level I trauma center. We determined whether the rolling average of CRI values over 60 s (CRI trend [CRI-T]) predicts in-hospital diagnosis of hemorrhagic shock, defined as blood product administration in the prehospital setting or within 4 h of hospital arrival. We hypothesized that lower CRI-T values would be associated with an increased likelihood of hemorrhagic shock and better predict hemorrhagic shock than prehospital vital signs. Results: Prehospital CRI was collected on 696 adult trauma patients, 21% of whom met our definition of hemorrhagic shock. The minimum CRI-T was 0.14 (interquartile range [IQR], 0.08-0.31) in those with hemorrhagic shock and 0.31 (IQR 0.15-0.50) in those without ( P = <0.0001). The positive likelihood ratio of a CRI-T value <0.2 predicting hemorrhagic shock was 1.85 (95% confidence interval [CI], 1.55-2.22). The area under the ROC curve (AUC) for the minimum CRI-T predicting hemorrhagic shock was 0.65 (95% CI, 0.60-0.70), which outperformed initial prehospital HR (0.56; 95% CI, 0.50-0.62) but underperformed EMS systolic blood pressure and shock index (0.74; 95% CI, 0.70-0.79 and 0.72; 95% CI, 0.67-0.77, respectively). Conclusions: Low prehospital CRI-T predicts blood product transfusion by EMS or within 4 hours of hospital arrival but is less prognostic than EMS blood pressure or shock index. The evaluated version of CRI may be useful in an austere setting at identifying injured patients that require the most significant medical resources. CRI may be improved with noise filtering to attenuate the effects of vibration and patient movement.
代偿储备指数（CRI）是一种非侵入性的连续测量指标，旨在检测血管内容量丢失。CRI由脉搏血氧饱和度波形得出，反映临床血流动力学失代偿前剩余的生理储备比例。方法：在这项前瞻性、观察性的院前队列研究中，我们对由紧急医疗服务（EMS）转运至一家一级创伤中心的受伤患者测量了CRI。我们确定CRI值在60秒内的滚动平均值（CRI趋势[CRI-T]）是否能预测院内出血性休克的诊断，出血性休克定义为院前或入院后4小时内输注血液制品。我们假设较低的CRI-T值与出血性休克的可能性增加相关，并且比院前生命体征能更好地预测出血性休克。结果：对696例成年创伤患者进行了院前CRI测量，其中21%符合我们对出血性休克的定义。出血性休克患者的最低CRI-T为0.14（四分位间距[IQR]，0.08 - 0.31），无出血性休克患者的为0.31（IQR 0.15 - 0.50）（P = <0.0001）。CRI-T值<0.2预测出血性休克的阳性似然比为1.85（95%置信区间[CI]，1.55 - 2.22）。预测出血性休克的最低CRI-T的ROC曲线下面积（AUC）为0.65（95%CI，0.60 - 0.70），优于初始院前心率（0.56；95%CI，0.50 - 0.62），但不如EMS收缩压和休克指数（分别为0.74；95%CI，0.70 - 0.79和0.72；95%CI，0.67 - 0.77）。结论：院前低CRI-T可预测EMS或入院后4小时内的血液制品输注，但预后价值不如EMS血压或休克指数。评估版的CRI在资源有限的环境中可能有助于识别需要最大量医疗资源的受伤患者。通过噪声滤波减弱振动和患者移动的影响可能会改善CRI。
