Division of Transfusion Medicine, Department of Pathology, Johns Hopkins University, Baltimore, Maryland, USA.
Biomedical Services, American Red Cross, Baltimore, Maryland, USA.
J Clin Apher. 2022 Oct;37(5):468-475. doi: 10.1002/jca.22004. Epub 2022 Aug 22.
Automated red cell exchange (RCE) is a common treatment for patients with sickle cell disease (SCD). Two key parameters are used to determine the volume of blood for RCE to reduce sickle hemoglobin (eg, HbS): fraction of cells remaining (FCR) and target hematocrit. We evaluated how the calculated FCR-using the manufacturer's algorithm-impacted blood utilization and incidence of acute care encounters.
Retrospective chart review was conducted of 15 adults with SCD who underwent chronic RCE from July 1, 2015 to August 31, 2019. Blood utilization and acute care encounters were compared across three time periods: (a) when a fixed FCR of 30% was used (12 months); (b) transition period during which physicians made ad hoc changes to the FCR (25 months); (c) algorithm phase when a procedural FCR between 30% and 50% was selected using an algorithm generated by the manufacturer's built-in software to target a HbS fraction of 8% post-procedure (12 months). Wilcoxon signed rank test was used to determine statistical significance.
Median blood utilization per procedure decreased from 2398 mL (interquartile range [IQR]: 2271-2759 mL) during the fixed FCR phase to 1887 mL (IQR: 1495-2241 mL) during the algorithm phase (P < 0.001). Similarly, median number of units transfused decreased from 10 (9-11) to 7 (5-9) during the respective phases (P < 0.001). Visits to the emergency department were 1 (0-4) in the fixed FCR phase and 0 (0-3) in the algorithm phase.
Algorithm-based selection of a procedural FCR significantly reduced blood utilization (~21%) without appearing to increase acute care encounters.
自动化红细胞置换（RCE）是治疗镰状细胞病（SCD）患者的常用方法。有两个关键参数用于确定 RCE 减少镰状血红蛋白（例如 HbS）的血量：细胞残留分数（FCR）和目标血细胞比容。我们评估了使用制造商的算法计算出的 FCR 如何影响血液利用和急性护理的发生。
对 2015 年 7 月 1 日至 2019 年 8 月 31 日期间接受慢性 RCE 的 15 名 SCD 成年患者进行了回顾性图表审查。在三个时间段内比较了血液利用和急性护理事件：（a）使用固定的 30%FCR 时（12 个月）；（b）在医生对 FCR 进行临时更改的过渡期间（25 个月）；（c）在算法阶段，使用制造商内置软件生成的算法选择程序 FCR 在 30%至 50%之间，以达到术后 HbS 分数 8%的目标（12 个月）。采用 Wilcoxon 符号秩检验确定统计学意义。
与固定 FCR 阶段的每个程序 2398ml（中位数[IQR]：2271-2759ml）相比，每个程序的中位血液利用量降低至算法阶段的 1887ml（IQR：1495-2241ml）（P<0.001）。同样，每个阶段的中位数输血单位数从 10（9-11）减少到 7（5-9）（P<0.001）。在固定 FCR 阶段就诊的急诊室为 1（0-4），在算法阶段为 0（0-3）。
基于算法的程序 FCR 选择显著降低了血液利用量（约 21%），而似乎并未增加急性护理的发生。
