Pham Huy P, Müller Marcella C, Williams Lance A, Juffermans Nicole P
Department of Pathology, University of Alabama at Birmingham, Birmingham, Alabama.
Department of Intensive Care Medicine, Academic Medical Center, Amsterdam, The Netherlands.
Transfusion. 2016 Apr;56(4):926-32. doi: 10.1111/trf.13447. Epub 2015 Dec 31.
Plasma transfusion is often used prophylactically in patients with coagulopathy. However, the doses transfused may not be adequate to normalize hemostatic tests, which are commonly used as surrogate markers in practice. Currently, there is no reliable way to predict the posttransfusion international normalized ratio (INR) after plasma transfusion. Therefore, our aim was to develop and validate a formula that can reliably estimate post-plasma transfusion INR.
A compartmental model was developed using demographic (sex, height, weight) and laboratory variables (hematocrit [Hct], INRinitial , and plasma volume transfused). The formula was validated using a data set from a multicenter trial conducted between May 2010 and June 2013 in critically ill, nonbleeding patients with coagulopathy, receiving prophylactic plasma transfusions. INR was measured just before and immediately after plasma transfusion.
Initial plasma volume is calculated using the patient's Hct and blood volume (derived from Nadler's formula). The estimated immediate posttransfusion INR is then calculated as [Formula: see text] There was a significant agreement between the model predictions and the actual INR measurements after transfusion. A total of 83% of the predictions were within the acceptable range of variation. Furthermore, there was no proportional difference or systemic bias between the predictions and the actual INR measurements.
This mathematical formula estimates posttransfusion INR after a certain volume of plasma transfusion with a good predictive ability. This formula, which only requires basic demographic and laboratory variables, may help the physicians to determine the volume of plasma required for a specific target INR in stable, nonbleeding patients.
血浆输注常用于有凝血功能障碍的患者的预防性治疗。然而，输注剂量可能不足以使止血试验结果恢复正常，而止血试验结果在实际中通常用作替代指标。目前，尚无可靠方法预测血浆输注后的国际标准化比值（INR）。因此，我们的目标是开发并验证一个能够可靠估算血浆输注后INR的公式。
利用人口统计学变量（性别、身高、体重）和实验室变量（血细胞比容[Hct]、初始INR以及输注的血浆量）建立了一个房室模型。使用2010年5月至2013年6月间在患有凝血功能障碍、接受预防性血浆输注的危重症非出血患者中进行的一项多中心试验的数据集对该公式进行验证。在血浆输注前和输注后立即测量INR。
初始血浆量通过患者的Hct和血容量（由纳德勒公式得出）计算得出。然后，输注后即刻的估计INR按[公式：见正文]计算。模型预测值与输注后实际INR测量值之间存在显著一致性。83%的预测值在可接受的变异范围内。此外，预测值与实际INR测量值之间不存在比例差异或系统偏差。
该数学公式对一定量血浆输注后的输注后INR具有良好的预测能力。这个仅需基本人口统计学和实验室变量的公式可能有助于医生确定稳定、非出血患者达到特定目标INR所需的血浆量。
