IEEE Trans Biomed Eng. 2021 Sep;68(9):2645-2653. doi: 10.1109/TBME.2020.3045916. Epub 2021 Aug 19.
Cerebral edema characterized as an abnormal accumulation of interstitial fluid has not been treated effectively. We propose a novel edema treatment approach to drive edematous fluid out of the brain by direct current utilizing brain tissue's electroosmotic property.
A finite element (FE) head model is developed and employed to assess the feasibility of the approach. First, the capacity of the model for electric field prediction is validated against human experiments. Second, two electrode configurations (S and D-montage) are designed to evaluate the distribution of the electric field, electroosmotic flow (EOF), current density, and temperature across the brain under an applied direct current.
The S-montage is shown to induce an average EOF velocity of 7e-4 mm/s underneath the anode by a voltage of 15 V, and the D-montage induces a velocity of 9e-4 mm/s by a voltage of 5 V. Meanwhile, the brain temperature in both configurations is below 38 °C, which is within the safety range. Further, the magnitude of EOF is proportional to the electric field, and the EOF direction follows the current flow from anode to cathode. The EOF velocity in the white matter is significantly higher than that in the gray matter under the anode where the fluid is to be drawn out.
The proposed electroosmosis based approach allows alleviating brain edema within the critical time window by direct current.
The approach may be further developed as a new treatment solely or as a complement to existing conventional treatments of edema.
脑水肿表现为间质液异常积聚,目前尚无有效的治疗方法。我们提出了一种新的脑水肿治疗方法,利用直流电通过脑组织的电渗流特性将水肿液从大脑中排出。
开发了一个有限元(FE)头部模型,并将其用于评估该方法的可行性。首先,通过与人体实验进行对比,验证模型对电场预测的能力。其次,设计了两种电极配置(S 和 D 导联),以评估在施加直流电时电场、电渗流(EOF)、电流密度和温度在大脑中的分布。
S 导联在施加 15 V 电压时,在阳极下诱导平均 EOF 速度为 7e-4 mm/s,而 D 导联在施加 5 V 电压时诱导速度为 9e-4 mm/s。同时,两种配置下的大脑温度均低于 38°C,处于安全范围内。此外,EOF 的大小与电场成正比,EOF 方向与电流从阳极流向阴极的方向一致。在阳极下,即需要抽出液体的位置,白质中的 EOF 速度明显高于灰质中的 EOF 速度。
提出的基于电渗流的方法可以通过直流电在关键时间窗内缓解脑水肿。
该方法可以进一步开发为单独或作为现有水肿常规治疗的补充的新治疗方法。