Introduction:

The Activated Clotting Time (ACT) is commonly used to manage anticoagulation during cardiac surgery. The aim of this study was to compare the older manually operated Hemochron^® Response and the automated Hemochron^® Signature Elite.

Methods:

In this observational study the clinically relevant differences of both devices were investigated simultaneously, using duplicate measurements, in 29 patients who underwent a Coronary Artery Bypass Grafting (CABG) or Aortic Valve Replacement (AVR) in order to determine reliability, bias, and to detect which method has the lowest variation. Blood samples were obtained from the arterial line prior to surgery, after administration of 300 IU/kg heparin, 5 minutes after initiation of cardiopulmonary bypass and successively every 30 minutes, and after protamine administration.

Results:

A total of 202 measurements were performed. Of these 10 measurements were out of range in the Response and 9 in the Elite. About 27 single unstable magnet errors were seen in the Response versus no measurement errors in the Elite. No statistically significant differences between the Response (p = 0.22, Wilcoxon rank) and Elite (p = 0.064) duplicates were observed. The Response values were consistently higher during heparinization than the Elite measurements (p = 0.002, repeated measurements) with an average positive bias of around 56 seconds during heparinization (Bland-Altman). Overall, the coefficient of variation (CoV) increased during heparinization.

Conclusion:

The Elite was more reliable, but the variation was higher for the Elite than the Response. The observed positive bias in the Response compared to the Elite could affect heparin administration during surgery making the two systems not interchangeable.

中文翻译：

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心胸外科手术期间活化凝血时间的临床监测：比较 Hemochron® Response 和 Hemochron® Signature Elite

介绍：

活化凝血时间 (ACT) 通常用于管理心脏手术期间的抗凝。本研究的目的是比较旧式手动操作的 Hemochron ^® Response 和自动化的 Hemochron ^® Signature Elite。

方法：

在这项观察性研究中，对 29 名接受冠状动脉旁路移植术 (CABG) 或主动脉瓣置换术 (AVR) 的患者使用重复测量同时研究了两种装置的临床相关差异，以确定可靠性、偏倚和检测哪种方法的变化最小。在手术前、施用 300 IU/kg 肝素后、开始体外循环后 5 分钟并连续每 30 分钟一次以及鱼精蛋白施用后，从动脉管路采集血样。

结果：

总共进行了 202 次测量。Response 中有 10 个测量值超出范围，Elite 中有 9 个测量值超出范围。在 Response 中发现了大约 27 个单一的不稳定磁体错误，而在 Elite 中则没有测量错误。观察到响应（p = 0.22，Wilcoxon 等级）和精英（p = 0.064）重复之间没有统计学上的显着差异。肝素化过程中的响应值始终高于 Elite 测量值（p = 0.002，重复测量），肝素化过程中的平均正偏差约为 56 秒 (Bland-Altman)。总体而言，变异系数 (CoV) 在肝素化过程中增加。

结论：

Elite 更可靠，但 Elite 的变化比 Response 高。与 Elite 相比，在 Response 中观察到的正偏差可能会影响手术期间的肝素给药，从而使这两个系统不可互换。