代偿储备测量优于休克指数，可早期、准确地检测到中心血容量减少的状态。

Superiority of compensatory reserve measurement compared with the Shock index for early and accurate detection of reduced central blood volume status.

机构信息

From the Battlefield Health & Trauma Center for Human Integrative Physiology US Army Institute of Surgical Research (V.A.C., N.J.K., T.D.L., J.B.L.), JBSA Fort Sam Houston, Texas; Department of Medicine (V.A.C.), Uniformed Services University, Bethesda, Maryland; Department of Emergency Medicine (V.A.C.), University of Texas Health, San Antonio, Texas; ATEM Ltd. (P.T.), United Kingdom; and Naval Medical Research Unit-San Antonio (S.C.), JBSA Fort Sam Houston, Texas.

出版信息

J Trauma Acute Care Surg. 2023 Aug 1;95(2S Suppl 1):S113-S119. doi: 10.1097/TA.0000000000004029. Epub 2023 May 17.

DOI:10.1097/TA.0000000000004029

PMID:37199525

原文链接:https://pmc.ncbi.nlm.nih.gov/articles/PMC10389397/

Abstract

BACKGROUND

Shock index (SI) equals the ratio of heart rate (HR) to systolic blood pressure (SBP) with clinical evidence that it is more sensitive for trauma patient status assessment and prediction of outcome compared with either HR or SBP alone. We used lower body negative pressure (LBNP) as a human model of central hypovolemia and compensatory reserve measurement (CRM) validated for accurate tracking of reduced central blood volume to test the hypotheses that SI: (1) presents a late signal of central blood volume status; (2) displays poor sensitivity and specificity for predicting the onset of hemodynamic decompensation; and (3) cannot identify individuals at greatest risk for the onset of circulatory shock.

METHODS

We measured HR, SBP, and CRM in 172 human subjects (19-55 years) during progressive LBNP designed to determine tolerance to central hypovolemia as a model of hemorrhage. Subjects were subsequently divided into those with high tolerance (HT) (n = 118) and low tolerance (LT) (n = 54) based on completion of 60 mm Hg LBNP. The time course relationship between SI and CRM was determined and receiver operating characteristic (ROC) area under the curve (AUC) was calculated for sensitivity and specificity of CRM and SI to predict hemodynamic decompensation using clinically defined thresholds of 40% for CRM and 0.9 for SI.

RESULTS

The time and level of LBNP required to reach a SI = 0.9 (~60 mm Hg LBNP) was significantly greater ( p < 0.001) compared with CRM that reached 40% at ~40 mm Hg LBNP. Shock index did not differ between HT and LT subjects at 45 mm Hg LBNP levels. ROC AUC for CRM was 0.95 (95% CI = 0.94-0.97) compared with 0.91 (0.89-0.94) for SI ( p = 0.0002).

CONCLUSION

Despite high sensitivity and specificity, SI delays time to detect reductions in central blood volume with failure to distinguish individuals with varying tolerances to central hypovolemia.

LEVEL OF EVIDENCE

Diagnostic Test or Criteria; Level III.

摘要

背景

休克指数（SI）等于心率（HR）与收缩压（SBP）的比值，临床证据表明，与 HR 或 SBP 单独相比，SI 对创伤患者的状态评估和预后预测更敏感。我们使用下体负压（LBNP）作为中心血容量减少的人体模型和经过验证的代偿储备测量（CRM）来准确跟踪中心血容量减少，以检验以下假设：（1）SI 呈现中心血容量状态的晚期信号；（2）对预测血流动力学失代偿的发生显示出较差的敏感性和特异性；（3）不能识别发生循环性休克风险最大的个体。

方法

我们在 172 名人类受试者（19-55 岁）中测量 HR、SBP 和 CRM，在旨在确定对中心血容量减少的耐受性的渐进性 LBNP 期间，作为出血模型。随后，根据完成 60mmHg LBNP 的情况，将受试者分为高耐受性（HT）（n=118）和低耐受性（LT）（n=54）。确定 SI 和 CRM 之间的时间关系，并计算 CRM 和 SI 预测血流动力学失代偿的敏感性和特异性的受试者工作特征（ROC）曲线下面积（AUC），使用临床定义的 CRM 为 40%和 SI 为 0.9 的阈值。

结果

达到 SI=0.9（~~60mmHg LBNP）所需的 LBNP 时间和水平明显大于达到 CRM 为 40%时所需的水平（~~40mmHg LBNP）（p<0.001）。在 45mmHg LBNP 水平下，HT 和 LT 受试者的 SI 无差异。CRM 的 ROC AUC 为 0.95（95%CI=0.94-0.97），而 SI 为 0.91（0.89-0.94）（p=0.0002）。