In one embodiment of {HEAD ~ this system aspect} of {TAIL ~ the invention}, the first, second, and third anesthesia levels correspond to respective BIS levels, the anesthesia effect level is a BIS level, and the combined anesthesia signal is a combined BIS level signal 
In one embodiment of { HEAD ~ this system aspect } of { TAIL ~ the invention } , the first , second , and third anesthesia levels correspond to respective BIS levels , the anesthesia effect level is a BIS level , and the combined anesthesia signal is a combined BIS level signal
OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH