Hypnotic drug effects can be assessed as the presence or absence of standard clinical endpoints, such as tolerance to calling the person by name and tolerance to shake and shout

Antinociceptive drug effects can be assessed as the presence or absence of tolerance to tetanic stimulus

The Patient State Index is a processed, electroencephalographic-derived index that is considered by some to be a drug-independent representation of the depth of sedation and anesthesia

What This Article Tells Us That Is New:

A four-period randomized sequence crossover study determined the concentration–effect relationships for both propofol and sevoflurane, both with and without remifentanil coadministration, with effects measured as tolerance to standard stimuli and by the Patient State Index

The sevoflurane Patient State Index values associated with a 50% probability of tolerance to the standard stimuli were higher for than those for propofol