Welsby Ian J, McDonnell Elizabeth, El-Moalem Habib, Stafford-Smith Mark, Toffaletti John G
Department of Anesthesiology, Duke University Medical Center, Durham, NC 27710, USA.
J Clin Monit Comput. 2002 Jul;17(5):287-92. doi: 10.1023/a:1021298103264.
Our aim was to test the hypothesis that new activated clotting time (ACT) technology, with modifications to instruments and reagents designed to detect earlier clot formation, would be associated with more precise but lower results. A secondary objective was to evaluate the potential impact of any change in ACT measurement on heparin requirements during cardiopulmonary bypass (CPB).
We compared the precision of two newer ACT systems: Actalyke, Helena Laboratories, Beaumont, TX and Hemochron Response, International Technidyne Corporation, Edison, NJ and assessed their bias with reference to a standard ACT system (Hemochron 801, International Technidyne Corporation, Edison, NJ). Bland-Altman analysis was applied to 81 duplicate samples from 22 patients undergoing CPB or percutaneous coronary interventions (PCI), covering the full clinical range of ACT values. We also estimated the change in heparin dose required to use the Actalyke rather than the Hemochron 801 results, to achieve our target ACT for CPB (480 seconds), and used a mixed model to test for significance.
The precision of the Actalyke was superior to the Hemochron Response (mean difference of duplicates +/- 0.1% versus +/- 4.2%). There was no significant bias (p = 0.93) between the results from the standard analyzers (Hemochron 801 and Response), but the results from the modified system (Actalyke) were on average 18% lower than the Hemochron 801 (p < 0.0001). Estimated heparin requirements established that fifty percent of CPB patients would have required additional heparin (5000 to 17500 units), an average increase of 1060 units per patient (p = 0.05), if the Actalyke values were used to guide anticoagulation during CPB.
Our results support the hypothesis that the modified technology (Actalyke) is associated with more precise but lower ACT results. We estimated these lower values would lead to increased heparin dosing during CPB. The impact of this increase on bleeding after cardiac surgery with CPB is controversial and requires further study.
我们的目的是检验以下假设：经过改进的用于检测更早凝血形成的仪器和试剂的新型活化凝血时间（ACT）技术，将产生更精确但数值更低的结果。次要目的是评估ACT测量的任何变化对体外循环（CPB）期间肝素需求量的潜在影响。
我们比较了两种更新的ACT系统的精度：Actalyke（Helena Laboratories公司，得克萨斯州博蒙特）和Hemochron Response（国际技术公司，新泽西州爱迪生），并参照标准ACT系统（Hemochron 801，国际技术公司，新泽西州爱迪生）评估了它们的偏差。对22例接受CPB或经皮冠状动脉介入治疗（PCI）的患者的81份重复样本进行Bland-Altman分析，样本涵盖了ACT值的整个临床范围。我们还估计了使用Actalyke而非Hemochron 801的结果来达到CPB的目标ACT（480秒）所需的肝素剂量变化，并使用混合模型检验其显著性。
Actalyke的精度优于Hemochron Response（重复测量的平均差异为±0.1% 对 ±4.2%）。标准分析仪（Hemochron 801和Response）的结果之间无显著偏差（p = 0.93），但改进系统（Actalyke）的结果平均比Hemochron 801低18%（p < 0.0001）。估计的肝素需求量表明，如果在CPB期间使用Actalyke值来指导抗凝，50%的CPB患者将需要额外的肝素（5000至17500单位），平均每位患者增加1060单位（p = 0.05）。
我们的结果支持以下假设：改进后的技术（Actalyke）与更精确但数值更低的ACT结果相关。我们估计这些较低的数值将导致CPB期间肝素剂量增加。这种增加对CPB心脏手术后出血的影响存在争议，需要进一步研究。
