Clinical application of a blood pressure autoregulation system during hypotensive anesthesia

A blood pressure autoregulation system based on the state-predictive contro l method was developed to minimize intraoperative blood loss and hence avoi d blood transfusion. In this report, the system is further improved by inco rporating fuzzy logic with a fail-safe function and an individual parameter -identifying function. The safety and stability of this system had been con firmed by preclinical experiments with dogs, Thereafter clinical applicatio n with 17 patients was conducted to maintain their mean arterial pressure a t around 60 mmHg during major surgery. The use of this system resulted in d ecreased blood loss and more speedy and accurate surgery due to a clearer s urgical field. Unwanted effects of hypotension were not observed clinically or in laboratory tests. This system is therefore safe, stable, and effecti ve in reducing the blood loss during major surgery that otherwise might cau se substantial blood loss.