From Metamark Genetics, Inc, Cambridge, MA.
Department of Mathematical Sciences, Elizabethtown College, Elizabethtown, PA.
Chest. 2011 Jul;140(1):48-53. doi: 10.1378/chest.10-2637. Epub 2011 Feb 24.
Catheter-related thrombosis is a common complication in all anatomic sites, especially when smaller veins of the upper extremity are considered. It is presumed that the presence of a catheter within the lumen of a vein will decrease flow and potentially create stasis, and clinical data suggest that the size of the catheter impacts thrombosis rates. We sought to determine, both mathematically and experimentally, the impact of catheters on fluid flow rates.
We used fluid mechanics to calculate relative flow rates as a function of the ratio of the catheter to vein diameters. We also measured the flow rate of a blood analyte solution in an annular flow model using diameters that simulate the size of upper extremity veins and commonly used peripherally inserted central catheters (PICCs).
We compared each of the derived relative flow rates to the experimentally determined ones for three cylinder sizes and found a correlation of r(2) = 0.90. We also confirmed that the decrease in fluid flow rate with each successive catheter size is statistically significant (P < .0001).
Our results demonstrate that fluid flow is dramatically decreased by the insertion of a centrally located obstruction. Assuming that blood flow in veins behaves in a similar manner to our models, PICCs, in particular, may substantially decrease venous flow rates by as much as 93%.
导管相关性血栓形成是所有解剖部位的常见并发症，尤其是在上肢较小的静脉中。人们认为静脉管腔内的导管会降低血流速度，并可能导致血流停滞，临床数据表明导管的大小会影响血栓形成的速度。我们旨在通过数学和实验的方法来确定导管对流体流动速率的影响。
我们利用流体力学来计算导管与静脉直径比值的相对流动速率。我们还使用模拟上肢静脉和常用外周中心静脉导管（PICC）大小的直径，在环形流动模型中测量血液分析物溶液的流速。
我们将三种不同大小的圆柱体的推导相对流速与实验确定的流速进行了比较，发现 r(2) = 0.90 的相关性。我们还证实，随着导管尺寸的逐个增加，流体流速的下降具有统计学意义（P <.0001）。
我们的结果表明，中央位置的障碍物插入会显著降低流体流动。假设静脉中的血流行为与我们的模型相似，PICC 可能会使静脉血流速度降低多达 93%。
