Multiple drug hemodynamic control by means of a supervisory-fuzzy rule-based adaptive control system: validation on a model

• Published in: IEEE transactions on biomedical engineering 1995-04, Vol.42 (4), p.371-385
• Main Authors: Held, C.M., Roy, R.J.
• Format: Article
• Language: English
• Subjects: Adaptation, Physiological; Adaptive control; Algorithms; Animals; Biological and medical sciences; Blood pressure; Blood Pressure - drug effects; Cardiac Output - drug effects; Control systems; Dogs; Dopamine - pharmacology; Drug Therapy, Combination; Drugs; Evaluation Studies as Topic; Expert systems; Feedback; Fuzzy Logic; Heart Failure - drug therapy; Heart Failure - physiopathology; Hemodynamics; Mathematical model; Medical sciences; Models, Cardiovascular; Nitroprusside - pharmacology; Pressure control; Radiotherapy. Instrumental treatment. Physiotherapy. Reeducation. Rehabilitation, orthophony, crenotherapy. Diet therapy and various other treatments (general aspects); Sensitivity and Specificity; Switches; Technology. Biomaterials. Equipments. Material. Instrumentation; Testing
• ISSN: 0018-9294; 1558-2531
• DOI: 10.1109/10.376130

A control device that uses an expert system approach for a two input-two output system has been developed and evaluated using a mathematical model of the hemodynamic response of a dog. The two inputs are the infusion rates of two drugs: sodium nitroprusside (SNP) and dopamine (DPM). The two controlled variables are the mean arterial pressure and the cardiac output. The control structure is dual mode, i.e., it has two levels: a critical conditions (coarse) control mode and a noncritical conditions (fine) control mode. The system switches from one to the other when threshold conditions are met. Different "controller parameters sets"-including the values. For the threshold conditions-can be given to the system which will lead to different controller outputs. Both control modes are rule-based, and supervisory capabilities are added to ensure adequate drug delivery. The noncritical control mode is a fuzzy logic controller. The system includes heuristic features typically considered by anesthesiologists, like waiting periods and the observance of a "forbidden dosage range" for DPM infusion when used as an inotrope. An adaptation algorithm copes with the wide range of sensitivities to SNP found among different individuals, as well as the time varying sensitivity frequently observed in a single patient. The control device is eventually tested on a nonlinear model, designed to mimic the conditions of congestive heart failure in a dog. The test runs show a highest overshoot of 3 mmHg with nominal SNP sensitivity. When tested with different simulated SNP sensitivities, the controller adaptation produces a faster response to lower sensitivities, and reduced oscillations to higher sensitivities. The simulations seem to show that the system is able to drive and adequately keep the two hemodynamic variables within prescribed limits.< >