I’m curious what mechanism is at work here.
Edit: Thanks for the responses. I get it now. Obviously I am still enjoying the discussion RE: the finer points like memory, etc.
In: Biology
You can’t wake up when you’re unconscious. Your brain is shut off. Your brain won’t respond to all those pain signals.
Since anasthesia is so dangerous they use less of it these days. Enough to disable motor activity so they can work on you but not enough to really shut down your nervous system.
Then they add another, safer drug that stops you from remembering anything that happens until they wake you up.
I just saw a video on this! Hopefully it was correct, someone can explain better than me for sure. But basically the anesthesia puts you in an unconscious state where the pain signals aren’t being received and processed. So basically, your body and nerves still “feel” everything, but the signal to the brain is blocked so you don’t experience it
Just an aside, but I recently heard a doctor (non-anesthesiologist) say the anesthesiologist’s job is to keep the surgery from killing you.
How general anesthesia works is not well understood.
Sleep is very different. Your brain is like a large office building: at night, the lights may mostly be off but the power is still on, there are still security guards, some people working through the night, maintenance crews, and so on. That’s sleep. Sleep is not your brain turning off, sleep is something your brain actively does. Importantly, while you are sleeping your brain still has the capacity to wake back up whenever it wants to, e.g. in response to external stimuli, including pain. You’ll also do things like shift position to stay comfortable, and so on.
Unconsciousness and general anesthesia are more like the building has been evacuated and the power is out. In that state, the brain can’t wake itself back up whenever it wants, and it doesn’t do things like shift your body around. Pain signals can reach the brain, but it’s like a burglar alarm going off when there’s nobody there to hear it. The physical/emotional sensation of pain (i.e. “hurting”) is something your brain does in response to pain signals; if your brain is mostly shut down, then pain can’t hurt.
All of which is why unconsciousness is so dangerous, and why general anesthesia is only done under the close supervision of an anesthesiologist.
I had surgery recently and there were actually two parts to the anaesthetic.
One was a nerve block that the anaesthetist directly injected into the nerves. This effectively paralysed my arm so I both lost feeling in it and any ability to move it for about 12 or so hours.
The other part was the general anaesthetic that knocked me out for the two or so hours the surgery took.
Your nit asleep durung anaesthesia, you are in a coma from drugs. A special type of sleep which you cant wake up from until drugs turn off. Some of drugs are very strong pain killers and sometimes special injections stop your nerves from carrying pain.
When your operation if finished the very cleaver doctors turn all those drugs off and you wakeup.
There’s a few interesting answers here, not all correct.
The real answer is that you do actually feel pain… you’re just not conscious. The inability to wake up is what seperates sleep from unconsciousness. You can’t wake up because of the drugs.
We can actually typically tell when an unconscious person is recieving painful stimuli due to spikes in heart rate, blood pressure etc.
To counteract this, general anaesthesia typically includes strong intravenous pain killers, or some other form of “blocking” pain – such as a nerve block.
General anesthesia is not just sleeping meds. Along with the sleeping drug (example – propofol or inhaled agents), you are also given multiple powerful painkillers (opioids like fentanyl etc.). The amount of painkillers will vary depending on the type and the invasiveness of the surgery. If the painkillers are not given, there will be a big spike in your vitals indicating that the pain receptors are still feeling the pain, even though you may be unconscious and not responding to pain. This is the reason you don’t feel pain under GA.
If someone induces general anesthesia, The Patient will get between 2 or 3 drugs
* An opioid from the group of fentanyl analogs or ketamine,
* a hypnotic such as propofol, thiopental, or etomidate,
* depending on the type and location of the procedure, also muscle relaxants such as succinylcholine or rocuronium
so in short, you get something
* for no pain
* for sleeping very good
* and for relaxing you muscles (you will not move and its easyer to put an tube down your throat
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