Moein Hadi, Menon Carlo
MENRVA Group, School of Engineering Science, Faculty of Applied Science, Simon Fraser University, 8888 University Drive, Burnaby, BC V5A 1S6, Canada.
Biomed Eng Online. 2014 Sep 11;13:135. doi: 10.1186/1475-925X-13-135.
Disorders associated with excessive swelling of the lower extremities are common. They can be associated with pain, varicose veins, reduced blood pressure when standing and may cause syncope or fainting. The common physical remedy to these disorders is the use of compression stockings and pneumatic compression leg massagers, which both attempt to limit blood pooling and capillary filtration in the lower limbs. However, compression stockings provide a constant pressure, and their efficiency has been challenged according to some recent studies. Air compression leg massagers on the other hand, restricts patient mobility. In this work we therefore present an innovative active compression bandage based on the use of a smart materials technology that could produce intermittent active pressure to mitigate the symptoms of lower extremity disorders.
An active compression bandage (ACB), actuated by shape memory alloy (SMA) wires, was designed and prototyped. The ACB was wrapped around a calf model to apply an initial pressure comparable to the one exerted by commercial compression stockings. The ACB was controlled to apply different values of compression. A data acquisition board and a LabVIEW program were used to acquire both the pressure data exerted by the ACB and the electrical current required to actuate the SMA wires. An analytical model of the ACB based on a SMA constitutive model was developed. An optimizer was implemented to identify optimal parameters of the model to best estimate the performance of the ACB.
The maximum increase in pressure due to the SMA wires activation was 40.8% higher than the initially applied pressure to the calf model. The analytical model of the ACB estimated the behaviour of the ACB with less than 0.32 mmHg difference with the experimental results.
The prototyped ACB was able to apply an initial compression comparable to the one applied by commercial compression stockings. Activation of the ACB resulted in an increase of compression up to 9.06 mmHg. Comparison between analytical and experimental results showed the analytical model was suitable to predict the behaviour of the ACB.
与下肢过度肿胀相关的疾病很常见。它们可能伴有疼痛、静脉曲张、站立时血压降低，还可能导致晕厥或昏厥。针对这些疾病的常见物理治疗方法是使用加压弹力袜和气动加压腿部按摩器，二者都试图限制下肢的血液淤积和毛细血管滤过。然而，加压弹力袜提供恒定压力，根据最近的一些研究，其效果受到了质疑。另一方面，空气加压腿部按摩器会限制患者活动。因此，在这项工作中，我们展示了一种基于智能材料技术的创新型主动加压绷带，它可以产生间歇性主动压力来减轻下肢疾病的症状。
设计并制作了一种由形状记忆合金（SMA）丝驱动的主动加压绷带（ACB）原型。将ACB缠绕在小腿模型上，以施加与商用加压弹力袜所施加压力相当的初始压力。控制ACB施加不同的压力值。使用数据采集板和LabVIEW程序来采集ACB施加的压力数据以及驱动SMA丝所需的电流。基于SMA本构模型开发了ACB的分析模型。实施了一个优化器来识别模型的最佳参数，以最好地估计ACB的性能。
由于SMA丝激活导致的压力最大增加量比最初施加到小腿模型上的压力高40.8%。ACB的分析模型估计ACB的行为与实验结果的差异小于0.32 mmHg。
ACB原型能够施加与商用加压弹力袜相当的初始压力。ACB的激活导致压力增加高达9.06 mmHg。分析结果与实验结果的比较表明，分析模型适合预测ACB的行为。
