Closed-loop coadministration of propofol and remifentanil guided by bispectral index: a randomized multicenter study.

BACKGROUND:We have developed a proportional-integral-derivative controller allowing the closed-loop coadministration of propofol and remifentanil, guided by a Bispectral Index (BIS) monitor, during induction and maintenance of general anesthesia. The controller was compared with manual target-contro