Corey F Scott, Walker William F
Product Development, Key Technologies, Inc., 40 East Cross Street, Baltimore, MD, 21230-5189, USA.
HemoSonics, LLC, 400 Preston Avenue, Suite 250, Charlottesville, VA, 22903, USA.
Ann Biomed Eng. 2016 May;44(5):1405-24. doi: 10.1007/s10439-015-1460-y. Epub 2015 Sep 23.
Uncontrolled bleeding threatens patients undergoing major surgery and in care for traumatic injury. This paper describes a novel method of diagnosing coagulation dysfunction by repeatedly measuring the shear modulus of a blood sample as it clots in vitro. Each measurement applies a high-energy ultrasound pulse to induce a shear wave within a rigid walled chamber, and then uses low energy ultrasound pulses to measure displacements associated with the resonance of that shear wave. Measured displacements are correlated with predictions from finite difference time domain models, with the best fit corresponding to the modulus estimate. In our current implementation each measurement requires 62.4 ms. Experimental data was analyzed using a fixed-viscosity algorithm and a free-viscosity algorithm. In experiments utilizing human blood induced to clot by exposure to kaolin, the free-viscosity algorithm quantified the shear modulus of formed clots with a worst-case precision of 2.5%. Precision was improved to 1.8% by utilizing the fixed-viscosity algorithm. Repeated measurements showed a smooth evolution from liquid blood to a firm clot with a shear modulus between 1.4 and 3.3 kPa. These results show the promise of this technique for rapid, point of care assessment of coagulation.
失控性出血对接受大手术及创伤性损伤护理的患者构成威胁。本文描述了一种通过在体外血液样本凝血过程中反复测量其剪切模量来诊断凝血功能障碍的新方法。每次测量都施加一个高能超声脉冲，以在刚性壁腔室内诱发剪切波，然后使用低能超声脉冲测量与该剪切波共振相关的位移。测量到的位移与有限差分时域模型的预测相关，最佳拟合对应于模量估计值。在我们当前的实现中，每次测量需要62.4毫秒。使用固定粘度算法和自由粘度算法对实验数据进行分析。在利用高岭土诱导人血凝血的实验中，自由粘度算法量化形成凝块的剪切模量，最坏情况下的精度为2.5%。通过使用固定粘度算法，精度提高到了1.8%。重复测量显示从液态血液到剪切模量在1.4至3.3千帕之间的坚实凝块有一个平稳的演变过程。这些结果表明了该技术在凝血快速床旁评估方面的前景。
