Very Few Know. This sounds like a non- answer, but let me explain. With modern anesthetics we try and shut down the memory of the patient before they go to the or. Once they can't remember what happened, it is very hard to find out what they felt as they went to sleep. Without sedatives the very medication that is used to put people to sleep blocks memory formation, so we have the same problem.
Relaxed, sleepy, out. General anesthesia in adults is usually started with intravenous medications. We often administer small doses of medications to help a patient feel relaxed (less anxiety) and a little sleepy just prior to giving a larger dose of medication for the full anesthesia effect. Some patients feel like they had a few drinks, some have a warm sensation in their face and chest, but most don't remember it!