Generally I remember everything up to the point where they give me the anaesthesia. But there was one occasion where I had a retroactive memory blackout that made me lose about a half hour before the operation began.
One of my sons had “light” anesthesia as a toddler so he would hold still for an MRI. The anesthesiologist told me he would be given enough of the drugs that he would be unconscious and unable to move, but he didn’t need as much as for a full operation because the “deeper” levels are to block pain. And, of course, here there would be no pain to block.
After the MRI, he woke up in the recovery room, happy and energetic. Babbled away, flirted with the nurses, played with the toys I’d laid in his bed… then just before we were going to be sent back to the outpatient clinic for another examination, he yawned, crawled onto my lap, and fell asleep in about five seconds 
The nap ended up being as long as his normal naps at that age, so I’d say the anesthesia “sleep” didn’t replace any restful sleep for him.
Anecdote time: Both times I had GA recently (once ankle surgery about 1-1.5 hrs, the other time upper GI endoscopy with propofol, procedural “sedation” my foot), waking up felt wonderful but I wanted to keep sleeping. Apparently, I take longer than the average patient to not be completely out of it. It was a little like waking up on a Saturday morning at the usual time when I started to come to - I had this wonderful feeling of having had great sleep, but I still needed more. I didn’t sit up for something like 2 hours after my surgery (according to my mom, who was very awake and starting to get impatient). I went through a dysphoric/teary period, slept another hour, and then rejoined the waking world, sort of. Both times, I pretty much went home and slept the rest of the day.
Aruvqan, these are the minimum numbers (in hours) for fasting for elective procedures in healthy patients, according to the American Society of Anesthesiologists (that doesn’t mean that some practitioners aren’t more conservative, but the evidence does not support extended periods of fasting):
Clear liquids - 2 hours
Light meal, milk - 6 hours
Fatty foods - 8+ hours
I have a book about sleep around here somewhere that describes what happens when humans are deprived of sleep long-term. It has testimony from POWs and concentration camp inmates in WWII who were tortured by sleep deprivation, and basically describes how the victims would eventually lose the ability to regulate their body temperature; when they started shivering uncontrollably the other people knew they were going to die soon, and sure enough, they would die soon after.
Weird, eh?
No, I can not use the liquiprep type bowel emptying stuff, so if they want me to be totally clean as a whistle, I need to just not eat solid foods … instead of most people who stop shitting their brains out, I continue for about a week. When one is crapping everything out as fast as it goes in, unless you end up on an IV one cant keep up with enough oral liquids to stay hydrated. When I dehydrate, it gets real ugly as in a migraine that makes me want to blow my head off that my meds do not even take the edge off of, a BP of 210/190, and a CPPD flare from hell [both feet end up with 3-4 cm edema] so it is clear liquids until I am squeeky clean. And that hospital strength immodium doesn’t even stop the shitting. 
Fatal familial insomnia would be an example in humans.
I had a hernia operation last Oct. The time that passed was more of a break in reality. I was talking with the anaesthesiologist while being wheeled into the operating room and then instantly I was looking at a clock in the recovery room, seemingly speaking without any real memory of the conversation. Apparently I had been talking with the recovery room people before I became “aware”.
So, put me down for “discontinuity”. They used Propofol.
For me it was restful, but I’m guessing it’s because I hadn’t slept well the last 48 hours, plus no pain med given would get rid of the eerie sensation of broken bones and accompanying tingling. So those couple of hours of “outness” were probably welcomed by my body.
When I had propofol the night I was admitted, that didn’t help much with rest (it helped momentarily with pain, though).
I’ve had 6 general anesthesia operations in the past 3 years. Five of them were on a day patient basis with no overnight stay in the hospital. Not once was I I told no food or drink for 24 hours. It was always no food or drink after midnight the night before. This was independent of my scheduled operation times which varied from 9 a.m. to 2 p.m.
I’m sorry I wasn’t clear, the numbers above are just for making sure your stomach is empty so you don’t vomit and aspirate, not for cleaning out from stem to stern. I am so glad I have never had to do a bowel prep, and I am amazed that more people don’t end up with problems from dehydrating/electrolyte imbalances.
I personally think that a lot of people cheat.
There is no practical reason you cannot drink plain water until 4 hours pre-op [except digestive issues of he body not processing the water because it as shut own.] Water clears out of the stomach quite quickly.
I agree - as above, the ASA has decided that there is no evidence supporting the practice of withholding clear liquids for greater than 2 hours before surgery in healthy patients with no risk factors for delayed stomach emptying. It’s actually to their advantage to have nice, juicy, non-dehydrated veins to poke, too, instead of the dehydrated ones of someone who hasn’t had anything to drink in 12+ hours (for afternoon appts).
Famial fatal insomnia and the non-hereditary sporadic fatal insomnia.
I’ve been put out a more than a couple times. I never found I became conscious feeling rested. I only felt like my body had been through a fatiguing ordeal and once puking sick as soon as food touched my mouth.
I received general anesthesia for a gallbladder operation. I didn’t dream and I wasn’t aware of any time passing from when I went under to when I came to several hours later. It’s more like the light switch was flipped off and then back on.
so why the fuck do they still do it?
Probably because doctors are a conservative lot. Sure, they probably don’t need to withhold liquids for twelve hours prior to surgery - but for most people, it isn’t harmful, and there’s a slight chance it may prevent a serious complication. When the only cost is a grouchy patient, why not do it?
I would argue that it’s dogma being held on to despite lack of evidence, which is a dangerous thing in general in a field where many preconceived notions of standard of care are now being questioned and challenged as neutral or even harmful (e.g., large fluid volumes given during anesthesia may INCREASE complications due to edema after the vasodilatory effects of anesthesia have worn off; see also, cricoid pressure controversy). It’s not clear yet, but it is plausible and perhaps likely that there is more harm from prolonged fasting pre-operative period than there is possible benefit when the data so far say that there is no additional benefit for long fasting periods in healthy patients.
Perhaps it’s easier to tell everybody to stop eating and drinking at midnight than to give them a list of when they can do what, since some people can not be relied upon to be able to do math or stick to directions. ???
I’ve been under general anesthesia three times - gallbladder, appendix, and tonsils. The time spent under wasn’t restful or restless. It just wasn’t.
Going under for my gallbladder, I saw the anesthesiologist push the plunger on a syringe plugged into my IV line, and poof, I was out. Waking up was a much slower process. First, the sound got turned on. Then, a limited sort of proprioception (why am I going boingboingboing? - It was because I had a mild seizure for which the nurse gave me something.) Then touch. Then very wobbly sight (my eyes worked, but holding my lids open was very difficult).
Same thing with my tonsils. Someone threw one big switch and turned me off. Then, when it was time to wake up, a series of much smaller switches were flipped on, the circuits warmed up, and the world came back.
Don’t really remember much of the appendix thing, mostly because I was scared out of my brain.
All I know is that after the shit from last spring I am no longer accepting blindly what I am told to do preop, but making my own decisions plain to the staff that I will not risk my health by accepting cookie cutter treatment. I go over every med I take, and we discuss how they interact with the meds they are proposing, and I categorically refuse to ever do a liquiprep/bowel prep ever again unless I am admitted and on IV hydration and under supervision the entire time. I obviously have ideosyncratic reactions to many common meds, and my life is not worth risking to blindly follow generic procedures any further. I daresay that if I had had the knowledge I have now about what happened with that session that gave me the hypertensive emergency, I would not be having cardiac issues now.