I opted out of anesthesia for my last colonoscopy, so that I could watch. (They still insisted on setting me up for potential sedation, I suppose in case I experienced distress mid-procedure, but it wasn't needed.) The procedure was quick (maybe 15 minutes); the discomfort was on the same order as a prostate exam, plus some pain of bloating that came and went repeatedly as pressurized air is used.
It seems the main dangers the anesthesiologist needs to watch for are those caused by the anesthesia itself, so going without it entirely felt like the safest option to me. And since I wasn't drugged, I could drive myself home and resume normal activities immediately. I suspect far more people could skip sedation for this procedure, and any risks (for example from some patients panicking) are likely outweighed by the extra care taken when a patient is a conscious observer.
This kind of brings up something I've thought of for a while...why isn't nitrous oxide (mixed with oxygen) used for stuff like this? Seems to be the best of both worlds... comfort/anti-anxiety for the patient (Nitrous has both pain-killing properties, and it's a dissociative, so it makes you much less aware of what's going on, as well as somewhat sedating), but unlike most sedatives administered via IV, since it's an inhaled gas onset/offset time is very quick - peak anesthesia is reached in 60-90 seconds, and after coming off gas you're back to baseline with-in 5 minutes.
Nitrous causes brain damage in medical staff. It damages cobalamin (vitamin B12), which is no big deal for a one-off exposure but for people to work with it every day causes problems. See:
I was awake during colonoscopy, too, no issues. I also was awake during screening of the stomach, where you have to swallow the stomach probe (or whatever it is). Not sure I would opt for that again.
It's quite common here in Germany. I know several doctors who routinely do it without anesthesia, to avoid the dangers of sedation. Having seen a colonoscopy done that way a few times, I'd personally insist on sedation. Most people I've personally observed who were awake for the procedure seemed to find it almost unbearably painful, although there was a minority who didn't mind it much.
The unique and worst part was the on-and-off air-bloating pain, but it was comparable to other quickly-passing episodes of intestinal gas/discomfort, and especially bearable knowing that it was very temporary and in service of a goal under expert care. (I've had more painful headaches, scrapes, stubbed-toes, and sprains – which each lasted longer.)
I could definitely understand those with various kinds of medical- and pain-anxiety opting for sedation, but I also think such things are highly suggestible and influenced by social norms about which pains are normal to shrug off and which pains you communicate for sympathy... so it doesn't surprise me that in other cultures skipping sedation could be the casually-accepted norm.
They didn't suggest it, but once I asked the only pushback was of the "most people prefer it, it's very safe, let's be ready to use it just in case" variety. (I hadn't expressed the preference until checking in that day, so the anesthesiologist was already scheduled, and I didn't save any money.)
To clarify, it was only prostate-exam-like at initial insertion, and total time of instrument-use may have even been less than 10 minutes. (I just remember being surprised how fast I was done and out, but didn't stopwatch-it. Next time, I'll probably time it and might even ask for a copy of the video.)
It seems the main dangers the anesthesiologist needs to watch for are those caused by the anesthesia itself, so going without it entirely felt like the safest option to me. And since I wasn't drugged, I could drive myself home and resume normal activities immediately. I suspect far more people could skip sedation for this procedure, and any risks (for example from some patients panicking) are likely outweighed by the extra care taken when a patient is a conscious observer.