The electromyogram (EMG) is available as a secondary trend on free-standing bispectral (BIS) index monitors. The EMG is that of the 'frontalis' forehead muscle & is every bit as real time as the EKG of the cardiac muscle. This EMG is also unaffected by either BOTOX or the use of neuromuscular blockers (NMBs).

A spike in the EMG is an indicator for more hypnotic (i.e. propofol). Propofol should be administered in boluses to drive the EMG spike back to the baseline (0 on the left hand BIS scale or 30 on the right hand EMG scale).

Titrating propofol to EMG spikes (reflections of incipient cortical arousal) also results in far fewer heart rate and blood pressure changes (reflections of primarily brain stem functions & unreliable guides to cortical activity).