AN OBSERVATIONAL TRIAL OF A COMPUTERIZED DRUG-DELIVERY SYSTEM ON 2 PATIENTS

A computerized drug delivery system has been designed and tested for a utomatic regulation of mean arterial blood pressure (MAP) of human pat ients by infusion of a vasodilator (sodium nitroprusside). Its control algorithm belongs to a type of long-range predictive control with a c ombination of finite-horizon and an infinite horizon optimization term s, The controller operates in an adaptive mode by using a recursive co ntrol-relevant identification algorithm for long-range predictive cont rol, A limited pilot study using the system to perform closed-loop reg ulation of MAP in two patients undergoing coronary artery bypass surge ry was performed, At all times the drug infusion was monitored by an e xpert supervisor who was immediately available to adjust/terminate the infusion if indicated. The trial results show that without human inte rvention, patients' MAP was kept within +/-10 mmHg of the setpoint for more than 70% of the time even in the presence of significant natural and unmeasurable disturbances. Further improvement to the overall con trol system such as adding supervisory control is needed.