Thanks for the detailed info.
I kinda like the nitrogen idea, because it’s quick. I’d forgotten about propofol—poor Michael Jackson showed that it results in deep and restful sleep with a thin margin of error.
The others sound rather complicated—several steps, and timing (although that’s ok for the condemned).
I thought you were going to tell me what was actually used to put down aging animals in veterinary practice. Those protocols sound more detailed than what I’d expect.
I’ve used a couple of those ways for animal euthanasia in practice. Sometimes it gets hard to procure certain drugs so we have to get inventive in the ways to humanely and compassionately put animals to sleep. The least we can do is let them go with some dignity.