So the nature of the problem is specifically in that the anesthetic would be used in the execution of a human.
You may have seen that death penalty lethal injection drugs are so hard to come by... So hard, in fact, that nitrogen is the experimental fallback...
The reason the drugs are so hard to come by and why we don't just use excessive anounts of morphine or fentanyl or what have you, is because the sources of these drugs have a stipulation on what they are to be used for. Many countries have abolished capital punishment. Take morphine for example. Australia, turkey and Spain are the main suppliers. None of them have capital punishment. If they found out we were using their morphine supplies to kill people... They can cut that supply off. Then folks in hospitals are out of luck.
This is why lethal injection drugs are always the roughest versions of drugs that we generally try not to have to use in hospitals if something else is better and available.
It's also why we can't just use scopalamine or twilight sleep or any really well used and proven anasthetic. It's too risky to end up losing access as a whole because a few thought it was providing some concept of justice against one.
