A reader writes:
Never mind depression -- Ketamine has already found important clinical use in emergency departments. We use it all the time for "procedural sedation" -- when we want to make patients comfortable before reducing a dislocated shoulder, fixing a broken bone, or maybe incising a draining a painful abscess. It starts working quickly after injection, acting as a powerful analgesic but also putting patients into a trancelike state. It wears off quickly, too -- and patients won't remember the event procedure, afterward.
Ketamine is safer than etomidate for blood pressure regulation during procedures, and doesn't carry the same risk as the old standby, fentanyl and versed, on respiratory depression. One risk of ketamine is called an "emergence phenomenon" -- really a bad trip, Sometimes patients emerge from the sedation very agitated and confused. To prevent this, we usually give a small dose of a benzo and patients feel fine.