Further improvement of blood pressure control system toward clinical use

• Published in: Jinko Zoki Vol. 24; no. 5; pp. 982 - 988
• Main Authors: FURUTANI, E, SAKAMOTO, T, ONODERA, H, MAETANI, S, IMAMURA, M, ARAKI, M
• Format: Journal Article
• Language: Japanese
• Published: JAPANESE SOCIETY FOR ARTIFICIAL ORGANS 1995; 一般社団法人 日本人工臓器学会
• Subjects: closed-loop blood pressure control system; fuzzy logic; identification of parameters; state-predictive control
• ISSN: 0300-0818; 1883-6097
• DOI: 10.11392/jsao1972.24.982

We improved our blood pressure control system by adding two functions to the previous state-predictive control system. One function to identifies the specific values of the three parameters to cope with individual variations. These parameters are gain, time-constant and dead time, characterizing the blood pressure response to hypotensive drugs. The other function is a fail-safe mechanism that uses fuzzy logic to incorporate clinicians' expertise. The experiments were performed using adult mongrel dogs anesthetized with GOF under controlled respiration. The mean arterial pressure (MAP), recorded from the femoral artery, was lowered using trimethaphan camsilate with the target pressure set at 60mmHg. After introduction of these functions, the initial overshoot decreased from the previous level of 21.0mmHg to a maximum of 6.3mmHg and the MAP was adjusted to the target value more quickly (3.5-6.8min) than before (5.0-30min). Furthermore, our new system evaluated the animals' conditions, responding to their abnormal status before their conditions became critical. These results indicated the clinical applicability of our system.