Monitoring the anti-nociceptive drug effect is useful because a sudden and strong nociceptive stimulus may result in untoward autonomic responses and muscular reflex movements. Unopposed stimulation may also 'overrule' a state of stable unconsciousness, with resultant awakening and awareness. The traditional clinical use of systolic or mean blood pressure is actually still one of the methods in everyday use for this monitoring purpose. Another cornerstone is the experience of which drugs and doses are effective in attenuating nociception. Alpiger and colleagues found that simple end-tidal monitoring of sevoflurane was a better predictor of nociceptive response than Auditory Evoked Potential.