A controller for regulation of mean arterial blood pressure using optimum nitroprusside infusion rate.

Automation of drug delivery for control of mean arterial blood pressure is highly desirable in a number of clinical applications. An integrating self-tuning control strategy for control of mean arterial blood pressure using sodium nitroprusside is presented. Next to robust performance, the most attractive feature of the controller is its capability to optimize the quantity of infused medication without introducing a bias in the blood pressure level; a problem that existed in some of the other adaptive control strategies that have been proposed previously. Further, the controller design requires only the knowledge of the pure delay and the order of the transfer function describing the patient's response to the medication; it does not require that the entire transfer function be specified. The derivation of the controller is not based on the patient response to sodium nitroprusside; indeed, it is a general adaptive control strategy for control of systems with transport delay. The controller performs robustly in the presence of variations in the patient response and successfully controls the pressure at the desired level. The ability of this strategy to reduce the amount of infused medication makes it potentially attractive for use in clinical applications, as large doses or long term use of sodium nitroprusside can adversely affect central nervous system and hematopoietic tissues.