From the Division of Trauma/Critical Care (D.J.M., A.D., J.S.P., K.J.B.), Department of Surgery, and Department of Radiology (P.T.), Medical College of Wisconsin, Milwaukee, Wisconsin.
J Trauma Acute Care Surg. 2013 Dec;75(6):1002-5; discussion 1005. doi: 10.1097/TA.0b013e3182a68756.
Flat inferior vena cava (IVC) has been associated with shock and mortality in young trauma patients (age < 55 years). Because of the greater possibility of nonhypovolemic shock in the elderly, we hypothesized that there would be no correlation between IVC ratio and the presence of shock.
We conducted a retrospective cohort study of all severely injured (Injury Severity Score [ISS] ≥ 15), blunt trauma patients 55 years or older from April 2006 to April 2011. Only patients undergoing axial imaging of the IVC within 1 hour of arrival were considered. Anteroposterior and transverse diameter of the IVC were measured 2.5 mm above the renal veins. Transverse-to-anteroposterior IVC ratios of 2, 3, and 4 were analyzed. Hemodynamic (heart rate, blood pressure, systolic blood pressure, shock index, and adjusted shock index [ASI]) and laboratory (hemoglobin, HCO, base excess) markers of shock were reviewed. Correlation among shock markers, IVC ratio, and death was analyzed using multivariate logistic regression. Relationship between shock and IVC ratio was analyzed using logistic regression and χ where appropriate.
A total of 308 patients met the inclusion criteria during the study period. The IVC ratio was greater than 2, greater than 3, and greater than 4 in 180, 85, and 46 patients, respectively. The IVC ratio (analyzed continuously) correlated with mortality (p < 0.05). Ratios of greater than 3 and greater than 4 predicted a 2.0 and 2.2 times mortality increase (95% confidence interval, 1.00-5.00 and 1.00-4.95, respectively). IVC ratio did not correlate with shock (ASI > 50) for any of the ratios studied.
As in previous studies with younger injured patients, a flat IVC is predictive of increased mortality risk in the elderly. Presence of a shock state, as defined by ASI, is not correlated with a flat IVC. Moreover, almost one third of patients presenting in shock had a round IVC. This is consistent with our hypothesis that shock in the elderly trauma population may be multifactorial and the risk of nonhypovolemic shock must be considered.
Diagnostic study, level IV.
下腔静脉变平与年轻创伤患者（<55 岁）的休克和死亡率相关。由于老年人发生非低血容量性休克的可能性更大，我们假设下腔静脉比与休克之间不存在相关性。
我们对 2006 年 4 月至 2011 年 4 月期间所有严重创伤（损伤严重程度评分[ISS]≥15）、钝挫伤且年龄≥55 岁的患者进行了回顾性队列研究。仅考虑在到达后 1 小时内行下腔静脉轴位成像的患者。在肾静脉上方 2.5mm 处测量下腔静脉的前后径和横径。分析下腔静脉的横径与前后径比值为 2、3 和 4 的情况。回顾了休克的血流动力学（心率、血压、收缩压、休克指数和调整后的休克指数[ASI]）和实验室（血红蛋白、HCO3、碱剩余）标志物。使用多元逻辑回归分析休克标志物、下腔静脉比与死亡之间的相关性。使用逻辑回归和 χ2 分析休克与下腔静脉比之间的关系。
研究期间共有 308 例患者符合纳入标准。180 例、85 例和 46 例患者的下腔静脉比分别大于 2、大于 3 和大于 4。下腔静脉比（连续分析）与死亡率相关（p<0.05）。比值大于 3 和大于 4 分别预测死亡率增加 2.0 和 2.2 倍（95%置信区间分别为 1.00-5.00 和 1.00-4.95）。对于研究的任何比值，下腔静脉比均与 ASI>50 定义的休克状态不相关。
与以前对年轻创伤患者的研究一样，扁平下腔静脉预示着老年患者的死亡风险增加。作为 ASI 定义的休克状态并不与扁平下腔静脉相关。此外，近三分之一出现休克的患者下腔静脉呈圆形。这与我们的假设一致，即老年创伤人群的休克可能是多因素的，必须考虑非低血容量性休克的风险。
诊断研究，IV 级。
