On using a self-tuning controller for blood pressure regulation during surgery in man.

The generalized minimum-variance self-tuning controller of Clarke and Gawthrop has been used to adjust the flow rate of a modified Vickers Treonic IP4 syringe pump delivering phenylephrine to 20 patients undergoing lower abdominal surgery during epidural analgesia. This proved to be a very effective method of restoring and maintaining normal arterial pressure. The method has also been used to produce controlled hypotension in 18 patients undergoing plastic or neurosurgical procedures via sodium nitroprusside infusions. Valuable insight into patient responses to surgical stimuli, blood loss, fluid loads, opioids, relaxants and other agents was provided.