Experiences with experimental clinical evaluation of a computerized drug delivery system for regulation of mean arterial blood pressure

A number of closed-loop control systems have been investigated and developed for the regulation of physiological variables by automatic administration of therapeutic agents. This paper reflects on several years of practical experience, by the authors, in this area including the development of an adaptive computerized drug delivery system. A computerized adaptive drug delivery system has been designed and tested for automatic regulation of mean arterial blood pressure (MAP) of patients by infusion of a vasodilator (sodium nitroprusside). A limited pilot study using the system to perform closed-loop regulation of MAP in two patients undergoing coronary artery bypass surgery was performed. At all times the drug infusion was monitored by an expert supervisor. The trial results show that without human intervention, patients´ MAP was kept within ±10 mmHg of the set-point for more than 70% of the time even in the presence of significant natural and unmeasurable disturbances