Held C M, Roy R J
Rensselaer Polytechnic Institute, Department of Biomedical Engineering, Troy, NY 12180, USA.
IEEE Trans Biomed Eng. 2000 Jan;47(1):115-23. doi: 10.1109/10.817626.
A rule-based system was designed to control the mean arterial pressure (MAP) and the cardiac output (CO) of a patient with congestive heart failure (CHF), using two vasoactive drugs: sodium nitroprusside (SNP) and dopamine (DPM). The controller has three different modes, that engage according to the hemodynamic state. The critical conditions control mode (CCC) determines the initial infusion rates, and continues active if the MAP or the CO fall outside of the defined criticality thresholds: an upper and a lower boundary for the MAP and a lower boundary for the CO. Inside the boundaries the control is performed by noncritical conditions control modes (NCC's), which are fuzzy logic controllers. If the CO is within normal range and the MAP is close to the goal range, then the MAP is driven using only SNP, in a single-input-single-output mode (NCC-SISO). Otherwise the NCC multiple-input-multiple-output is active (NCC-MIMO). The goal values for the controlled variables are defined as a band of 5 mmHg for the MAP and 5 mL/kg/min for the CO, but there is little concern for this application if the CO is too high (i.e., in practical terms the CO only needs to achieve a necessary minimum rate). The NCC-MIMO includes a gain adaptation algorithm to cope with the wide variety in sensitivities to SNP. Supervisory capabilities to ensure adequate drug delivery complete the controller scheme. After extensive testing and tuning on a CHF-hemodynamics nonlinear model, the control system was applied in dog experiments, which led to further enhancements. The results show an adequate control, presenting a fast response to setpoint changes with an acceptable overshoot.
设计了一种基于规则的系统，使用两种血管活性药物：硝普钠（SNP）和多巴胺（DPM），来控制充血性心力衰竭（CHF）患者的平均动脉压（MAP）和心输出量（CO）。该控制器有三种不同模式，根据血流动力学状态启动。危急情况控制模式（CCC）确定初始输注速率，如果MAP或CO超出定义的危急阈值（MAP的上限和下限以及CO的下限），则继续保持激活状态。在这些界限内，由非危急情况控制模式（NCC）进行控制，这些模式是模糊逻辑控制器。如果CO在正常范围内且MAP接近目标范围，则仅使用SNP以单输入单输出模式（NCC-SISO）驱动MAP。否则，NCC多输入多输出模式激活（NCC-MIMO）。控制变量的目标值定义为MAP有5 mmHg的范围，CO有5 mL/kg/min的范围，但如果CO过高（即实际上CO只需达到必要的最低速率），对于此应用而言影响不大。NCC-MIMO包括一种增益自适应算法，以应对对SNP敏感性的广泛差异。确保药物输送充足的监控功能完善了控制器方案。在对CHF血流动力学非线性模型进行广泛测试和调整后，该控制系统应用于犬类实验，从而实现了进一步改进。结果显示控制效果良好，对设定点变化响应迅速，超调量可接受。
