Department of Biostatistics and Data Science, The University of Texas Health Science Center at Houston, Houston, Texas.
Department of Acute, Chronic and Continuing Care, School of Nursing, University of Alabama at Birmingham, Birmingham, Alabama.
Transfusion. 2019 Aug;59(8):2699-2708. doi: 10.1111/trf.15334. Epub 2019 May 3.
The mortality of trauma patients requiring massive transfusion to treat hemorrhagic shock approaches 17% at 24 hours and 26% at 30 days. The use of stored RBCs is limited to less than 42 days, so older RBCs are delivered first to rapidly bleeding trauma patients. Patients who receive a greater quantity of older RBCs may have a higher risk for mortality.
Characterizing blood age exposure requires accounting for the age of each RBC unit and the quantity of transfused units. To address this challenge, a novel Scalar Age of Blood Index (SBI) that represents the relative distribution of RBCs received is introduced and applied to a secondary analysis of the Pragmatic, Randomized Optimal Platelet and Plasma Ratios (PROPPR) randomized controlled trial (NCT01545232, https://clinicaltrials.gov/ct2/show/NCT01545232). The effect of the SBI is assessed on the primary PROPPR outcome, 24-hour and 30-day mortality.
The distributions of blood storage ages successfully maps to a parameter (SBI) that fully defines the blood age curve for each patient. SBI was a significant predictor of 24-hour and 30-day mortality in an adjusted model that had strong predictive ability (odds ratio, 1.15 [1.01-1.29], p = 0.029, C-statistic, 0.81; odds ratio, 1.14 [1.02-1.28], p = 0.019, C-statistic, 0.88, respectively).
SBI is a simple scalar metric of blood age that accounts for the relative distribution of RBCs among age categories. Transfusion of older RBCs is associated with 24-hour and 30-day mortality, after adjustment for total units and clinical covariates.
需要大量输血治疗出血性休克的创伤患者，在 24 小时时的死亡率接近 17%，在 30 天时为 26%。储存的红细胞的使用时间限制在 42 天以内，因此，首先将较陈旧的红细胞输给大量出血的创伤患者。接受较多陈旧红细胞的患者死亡风险可能更高。
描述血液年龄暴露情况需要考虑每个红细胞单位的年龄和输注单位的数量。为了解决这个挑战，引入了一种新的血液年龄标度指数（SBI），该指数代表了接受的红细胞的相对分布，并应用于 Pragmatic, Randomized Optimal Platelet and Plasma Ratios (PROPPR) 随机对照试验（NCT01545232，https://clinicaltrials.gov/ct2/show/NCT01545232）的二次分析。SBI 的效果是通过评估对 PROPPR 的主要结局（24 小时和 30 天死亡率）来评估的。
血液储存年龄的分布成功映射到一个参数（SBI），该参数完全定义了每个患者的血液年龄曲线。在调整后的模型中，SBI 是 24 小时和 30 天死亡率的显著预测因素，该模型具有很强的预测能力（比值比，1.15[1.01-1.29]，p=0.029，C 统计量，0.81；比值比，1.14[1.02-1.28]，p=0.019，C 统计量，0.88）。
SBI 是一个简单的血液年龄标度指标，它考虑了红细胞在不同年龄组之间的相对分布。在调整了总单位数和临床协变量后，输注较陈旧的红细胞与 24 小时和 30 天死亡率相关。
