Human Friendly Clinical Control of Respiration to Deal with Difference of Individual Characteristics

Abstract

A basic framework of a clinical control method is developed that is generally consistent with differences of individual subjects. A discrete-time control system is synthesized on the basis of an adaptive pole-placement method, which is capable of compensating characteristic and environmental changes of a controlled object. It is applied to the control of alveolar CO 2 -concentration both in a controlled and an assisted respiration, resulting in a stable control of alveolar CO 2 -concentration dealing with a different characteristics of a respiratory regulation system in different sampling intervals as well as its individual difference, non-linearities and chronic change. An experimental system is composed of a newly developed programmable respirator with its controlling and measuring devices and software. From clinical experiments on healthy subjects, its performance is examined to followup a given desired alveolar CO 2 -concentration with its clinical safety. First, the necessity and method of an adaptive control are first described, which is effective to the control of a respiratory regulation system with various kinds of unknown and ambiguous characteristics of individuals. Then, clinical contribution of the proposed method is discussed on the basis of the experimental results under different conditions.