Department of Medical Physics, University Hospitals of Leicester NHS Trust, Infirmary Square, Leicester LE1 5WW, UK.
Med Biol Eng Comput. 2013 Jun;51(6):709-18. doi: 10.1007/s11517-013-1040-y. Epub 2013 Feb 7.
The assessment of cerebrovascular regulatory mechanisms often requires flexibly controlled and precisely timed changes in arterial blood pressure (ABP) and/or inspired CO₂. In this study, a new system for inducing variations in mean ABP was designed, implemented and tested using programmable sequences and programmable controls to induce pressure changes through bilateral thigh cuffs. The system is also integrated with a computer-controlled switch to select air or a CO₂/air mixture to be provided via a face mask. Adaptive feedback control of a pressure generator was required to meet stringent specifications for fast changes, and accuracy in timing and pressure levels applied by the thigh cuffs. The implemented system consists of a PC-based signal analysis/control unit, a pressure control unit and a CO₂/air control unit. Initial evaluations were carried out to compare the cuff pressure control performances between adaptive and non-adaptive control configurations. Results show that the adaptive control method can reduce the mean error in sustaining target pressure by 99.57 % and reduce the transient time in pressure increases by 45.21 %. The system has proven a highly effective tool in ongoing research on brain blood flow control.
脑血管调节机制的评估通常需要灵活控制和精确计时的动脉血压 (ABP) 和/或吸入 CO₂ 的变化。在这项研究中，设计、实现并测试了一种新的系统，该系统使用可编程序列和可编程控制通过双侧大腿袖带诱导平均 ABP 的变化。该系统还与计算机控制的开关集成在一起，以选择通过面罩提供空气或 CO₂/空气混合物。压力发生器的自适应反馈控制需要满足快速变化、大腿袖带施加的定时和压力水平的严格规范。实现的系统包括基于 PC 的信号分析/控制单元、压力控制单元和 CO₂/空气控制单元。进行了初步评估，以比较自适应和非自适应控制配置之间的袖带压力控制性能。结果表明，自适应控制方法可以将维持目标压力的平均误差降低 99.57%，并将压力增加的瞬态时间减少 45.21%。该系统已被证明是正在进行的脑血流控制研究的有效工具。
