Murray D, Pennell B, Olson J
Department of Anesthesia, Washington University School of Medicine, St. Louis, Missouri, USA.
Transfusion. 1999 Jan;39(1):56-62. doi: 10.1046/j.1537-2995.1999.39199116895.x.
Prothrombin time (PT) and activated partial thromboplastin time (APTT) are used to diagnose causes of increased surgical bleeding and to guide treatment of acquired coagulation factor deficiency. This study compared the sensitivity of various commercial PT and APTT tests in patients with dilutional coagulopathy.
A prospective study was used to identify patients who experienced increased surgical bleeding during elective extensive (>10 spinal segments) spinal fusion and instrumentation. In patients with clinical signs of increased bleeding, blood was obtained to compare the sensitivity of various commercial PT and APTT tests. PT, PT ratio, the International Normalized Ratio (INR), APTT, and APTT ratio were compared for their sensitivity in the diagnosis of a dilutional coagulopathy.
Sixteen patients experienced increased bleeding during surgery. Mean estimated blood volume lost exceeded 1 blood volume (1.14 +/- 0.28). PT and APTT test results varied markedly. In the most sensitive PT and APTT tests, the results were 1.5 times the mean reference range values in all but on of the patients. The least sensitive combination of tests had results that were 1.5 times the mean reference range values in only 2 of 16 patients. Variability among tests was not reduced by the use of the PT or the APTT ratio, by the use of INR, or by incorporation of a measure of PT or APTT test sensitivity to factor-deficient serum.
In surgical patients with dilutional coagulopathy, diagnostic and treatment decisions could depend on which PT and APTT test was used to determine the etiology of increased bleeding. This study indicates that the relationship between increased bleeding and an increased PT and APTT may be more difficult to define than is suggested by current practice guidelines. Each laboratory must establish guidelines based on reagent and instrument sensitivity to coagulation factor dilution.
凝血酶原时间（PT）和活化部分凝血活酶时间（APTT）用于诊断手术出血增加的原因并指导获得性凝血因子缺乏的治疗。本研究比较了各种商用PT和APTT检测对稀释性凝血病患者的敏感性。
采用前瞻性研究来确定在择期广泛（>10个脊柱节段）脊柱融合和内固定手术期间出现手术出血增加的患者。对于有出血增加临床体征的患者，采集血液以比较各种商用PT和APTT检测的敏感性。比较PT、PT比值、国际标准化比值（INR）、APTT和APTT比值在诊断稀释性凝血病方面的敏感性。
16例患者在手术期间出现出血增加。平均估计失血量超过1个血容量（1.14±0.28）。PT和APTT检测结果差异显著。在最敏感的PT和APTT检测中，除1例患者外，所有患者的结果均为平均参考范围值的1.5倍。最不敏感的检测组合在16例患者中只有2例结果为平均参考范围值的1.5倍。使用PT或APTT比值、使用INR或纳入PT或APTT检测对因子缺乏血清敏感性的测量，均未降低检测之间的变异性。
在患有稀释性凝血病的手术患者中，诊断和治疗决策可能取决于使用哪种PT和APTT检测来确定出血增加的病因。本研究表明，出血增加与PT和APTT升高之间的关系可能比当前实践指南所建议的更难界定。每个实验室必须根据试剂和仪器对凝血因子稀释的敏感性制定指南。
