What is the level of unconsciousness during anesthesia? Is it "sleep-like" unconsciousness or "neurons do basically nothing" level? Whenever I read about anesthesia I am wondering if we are not accidentally killing people (and creating new ones) like in teletransportation paradox. https://en.wikipedia.org/wiki/Teletransportation_paradox
Just anecdata, but I was under a few times as kid. It was like teleporting into the future. Last memory was being told to count backwards, next memory was waking up in the recovery room.
Apparently I had a small anesthetic overdose in the hospital as a kid and woke up a day or two later than expected, but from my perspective, nothing happened and I just went to sleep then woke up.
Depends on the "kind" of anesthesia, on the medication used and on the specific reaction of the patient to that medication.
For example there is stuff like Ketamine, which in some cases can live up to its other use as a recreational drug and give the patient very colorful dreams. There are sedatives that just take away the capacity to form memories, but leave you awake and aware, just calmer. In cases like some knee surgeries, it is possible to leave the patient fully awake, just paralyze and numb the legs.
To add to the examples others have given there is also some that makes you not feel pain but you do remain semi-conscious and when so can still form permanent memories. This is called conscious sedation. They can adjust your level of consciousness as they go, so they can make you more aware if they have to ask questions or need to you do something like move a body part for them and make you less aware when they don't need any interaction.
It combines a sedative from the benzodiazepine family with a synthetic opioid painkiller. This is the most common sedation for colonoscopies. I had a colonoscopy using this, with fentanyl as the opioid and probably midazolam for the benzodiazepine (if not that probably diazepam).
I was aware of the doctor starting the procedure and felt something cold. I could feel pushing sometimes. But nothing hurt or was even annoying (except that cold right at the start). I remember being asked how I was doing and answering. I remember the doctor talking about the quality of my prep--the laxatives had not been as effective as they could have been--and noting that it was still good enough to allow them to continue.
There are some gaps so I think at some points I was more out of it.
I had an earlier colonoscopy with deep sedation using propofol. Here's the experience with that: (1) they start it and I have maybe 10 seconds of memories after that point. At this point I wasn't even in the procedure room. I was in a bed in a waiting area. (2) My next memory is waking up, in the same waiting area, with a nurse telling me they are done, putting the basket with my pants and glasses and phone on the bed, and telling me I could put my pants on.
I've got no memory of being wheeled into the procedure area, or of anything that happened there, or being wheeled back.
That doesn't necessarily mean I didn't feel anything during the procedure. When we were going over the sedation options when arranging for that colonoscopy I asked if deep sedation means you don't feel anything at all, and all the doctor would say is that I would not have any memories of anything.
That isn't exactly reassuring.
If someone offered to pay me a large amount of money to undergo a couple of hours or horrible torture with a guarantee that they would give me a drug to prevent forming long term memories of that torture I would not accept. I would be too worried that there could be other negative persistent effects of such mental trauma than just the formation of long term recallable memories and that the memory preventing drug would not stop those other effect.
