Despotis G J, Santoro S A, Spitznagel E, Kater K M, Barnes P, Cox J L, Lappas D G
Department of Anesthesiology, Washington University Medical Center, St. Louis, Missouri 63110.
Anesthesiology. 1994 Feb;80(2):338-51. doi: 10.1097/00000542-199402000-00014.
Although available hemostasis assays from institutional laboratories permit an analytical approach to diagnosis and treatment of coagulation disorders following cardiopulmonary bypass, their clinical utility has been limited by delays in obtaining results. The development of instrumentation for on-site testing allows rapid return of results. This study was designed to compare whole blood (WB) results obtained from on-site coagulation assays with values provided by our institutional laboratory (LAB).
After Institutional Human Studies Committee approval, 362 patients presenting for cardiac surgery requiring cardiopulmonary bypass were enrolled in this study. Prothrombin time (PT), activated partial thromboplastin time (aPTT), and platelet count (PLT) assays were performed in both WB and LAB systems. PT, aPTT, and PLT measurements were compared between WB and LAB assays using blood specimens obtained from at least two time points for each patient. Normal range values for both PT and aPTT methods were determined by using measurements from a normal reference population. Coagulation factor levels were measured in a subset of patients to characterize the response of PT and aPTT assays to individual and multiple factor levels. To employ Bayes' theorem and calculate predictive indexes (e.g., sensitivity, specificity), the disease or factor deficiency was determined using factor levels. Predictive indexes were used to evaluate the ability of PT and aPTT assays to identify factor deficiency.
PLT counts were similar between systems. Linear regression and bias analysis demonstrated similar results for WB and LAB PT and discordant results for aPTT measurements. Both PT assays had a similar normal range, whereas a wider distribution of results was evident for the WB aPTT normal range. Although statistically greater slopes for factor:aPTT regressions were observed for the WB system, WB aPTT correlated better with factor V and with factor V, VIII, and XII levels (multivariate linear regression). Diagnostic performance for factor levels less than 0.3 and 0.4 U/ml was similar for both WB and laboratory PT and aPTT assays. WB and LAB PT and aPTT assays performed similarly in detecting factor deficiency in the period after cardiopulmonary bypass.
WB PT and PLT values correlate well with those obtained from the LAB. The discrepancy between measurement systems in aPTT values is probably a reflection of both different normal ranges and responsiveness to factor deficiency. These WB assays provide coagulation results that can accurately identify patients with quantitative deficiencies in platelets and coagulation factors.
尽管机构实验室现有的止血检测方法允许采用分析方法来诊断和治疗体外循环后的凝血障碍，但其临床应用受到获取结果延迟的限制。现场检测仪器的发展使得结果能够快速返回。本研究旨在比较现场凝血检测获得的全血（WB）结果与我们机构实验室（LAB）提供的值。
经机构人类研究委员会批准，362例需要体外循环的心脏手术患者纳入本研究。在WB和LAB系统中均进行了凝血酶原时间（PT）、活化部分凝血活酶时间（aPTT）和血小板计数（PLT）检测。使用从每位患者至少两个时间点采集的血标本，比较WB和LAB检测中的PT、aPTT和PLT测量值。PT和aPTT方法的正常范围值通过使用正常参考人群的测量值来确定。在一部分患者中测量凝血因子水平，以表征PT和aPTT检测对单个和多个因子水平的反应。为了应用贝叶斯定理并计算预测指标（如敏感性、特异性），使用因子水平确定疾病或因子缺乏情况。预测指标用于评估PT和aPTT检测识别因子缺乏的能力。
两个系统的PLT计数相似。线性回归和偏差分析表明，WB和LAB的PT结果相似，而aPTT测量结果不一致。两种PT检测的正常范围相似，而WB的aPTT正常范围的结果分布更广泛。尽管在WB系统中观察到因子:aPTT回归的斜率在统计学上更大，但WB的aPTT与因子V以及因子V、VIII和XII水平的相关性更好（多变量线性回归）。对于因子水平低于0.3和0.4 U/ml的情况，WB和实验室的PT及aPTT检测的诊断性能相似。在体外循环后的时期，WB和LAB的PT及aPTT检测在检测因子缺乏方面表现相似。
WB的PT和PLT值与LAB获得的值相关性良好。aPTT值在测量系统之间的差异可能反映了不同的正常范围以及对因子缺乏的反应性。这些WB检测提供的凝血结果能够准确识别血小板和凝血因子定量缺乏的患者。
