Tabi Meir, Padkins Mitchell, Burstein Barry, Younis Anan, Asher Elad, Bennett Courtney, Jentzer Jacob C
Department of Cardiovascular Medicine, Mayo Clinic, Rochester, MN, United States of America; Jesselson Integrated Heart Center, Shaare Zedek Medical Center, Jerusalem, Israel.
Department of Cardiovascular Medicine, Mayo Clinic, Rochester, MN, United States of America.
J Crit Care. 2024 Feb;79:154445. doi: 10.1016/j.jcrc.2023.154445. Epub 2023 Oct 25.
A high shock index (SI), the ratio of heart rate (HR) to systolic blood pressure (SBP), has been associated with unfavorable outcomes. We sought to determine the hemodynamic underpinnings of an elevated SI using 2-D and doppler Transthoracic Echocardiography (TTE) in unselected cardiac intensive care unit (CICU) patients.
We included Mayo Clinic CICU admissions from 2007 to 2018 who were in sinus rhythm at the time of TTE. The SI was calculated using HR and SBP at the time of TTE. Patients were grouped according to SI: <0.7, 4012 (64%); 0.7-0.99, 1764 (28%); and ≥ 1.0, 513 (8%). Pearson's correlation coefficient was used to assess associations between continuous variables.
We included 6289 unique CICU patients, 58% of whom had acute coronary syndrome. The median age was 67.9 years old and 37.8% were females. The mean SI was 0.67 BPM/mmHg. As the SI increased, markers of left ventricular (LV) systolic function and forward flow decreased, including left ventricular ejection fraction (LVEF), fractional shortening, left ventricular outflow tract (LVOT) velocity time integral (VTI), stroke volume, LV stroke work index, and cardiac power output. Biventricular filling pressures increased, and markers of right ventricular function worsened with rising SI. Most TTE measurements reflecting LV function and forward flow were inversely correlated with SI, including LV stroke work index (r = -0.59) and LVOT VTI (r = -0.41), as were both systemic vascular resistance index (r = -0.43) and LVEF (r = -0.23).
CICU patients with elevated SI have worse biventricular function and systemic hemodynamics, particularly decreased stroke volume and related calculated TTE parameters. The SI is an easily available marker that can be used to identify CICU patients with unfavorable hemodynamics who may require further assessment.
高休克指数（SI），即心率（HR）与收缩压（SBP）之比，与不良预后相关。我们试图通过二维和多普勒经胸超声心动图（TTE）来确定未选择的心脏重症监护病房（CICU）患者SI升高的血流动力学基础。
我们纳入了2007年至2018年梅奥诊所CICU的入院患者，这些患者在进行TTE检查时处于窦性心律。SI通过TTE检查时的HR和SBP计算得出。患者根据SI分组：<0.7，4012例（64%）；0.7 - 0.99，1764例（28%）；≥1.0，513例（8%）。采用Pearson相关系数评估连续变量之间的关联。
我们纳入了6289例独特的CICU患者，其中58%患有急性冠状动脉综合征。中位年龄为67.9岁，37.8%为女性。平均SI为0.67次/分/毫米汞柱。随着SI升高，左心室（LV）收缩功能和前向血流的指标下降，包括左心室射血分数（LVEF）、缩短分数、左心室流出道（LVOT）速度时间积分（VTI）、每搏输出量、左心室每搏功指数和心脏功率输出。双心室充盈压升高，右心室功能指标随SI升高而恶化。大多数反映LV功能和前向血流的TTE测量值与SI呈负相关，包括左心室每搏功指数（r = -0.59）和LVOT VTI（r = -0.41），全身血管阻力指数（r = -0.43）和LVEF（r = -0.23）也是如此。
SI升高的CICU患者双心室功能和全身血流动力学较差，尤其是每搏输出量和相关的TTE计算参数降低。SI是一个易于获得的指标，可用于识别可能需要进一步评估的血流动力学不良的CICU患者。
