I recall a vet first administering a sedative via injection and then a few minutes later injecting the drug pentobarbital to stop the heart as a double injection given to optimize peaceful and painless death of a pet cat or dog.
Today when euthanizing our 20 year old cat, only one injection was given and I would like to know if this is acceptable as a humane euthanasia as when a pre injection sedative is given before.
The same thing happened to me last year and our cat's passing was not peaceful. In hindsight I wish I had asked a lot more questions before the euthanasia, but expected the vet to care as much about my cat as I did. That was a mistake. The procedure was rushed and not explained properly to us. After talking to other people that have had pets euthanized in the past I realized that a sedative is usually given. I think the reason some vets don't do this is because they want to get you in and out as quickly as possible. We were in the vets office for about 2 minutes, if that. It was very distressing. In future I would make an appointment to talk through how they planned to do the procedure before taking my pet anywhere near the vet. If I didn't like what I was hearing I would find another vet.
This makes me sick. I had my cat done 18 months ago and was not able to watch it. I really hope that he did not suffer.

a good vet will care about your cat and you,,, yes there should be a sedative,,,, and i have always stayed in the room to hold my cat as he passed,,,, a good vet will allow you to be in the room also for a while after to cry and hold your pet....... if the cat is very old, and mine have been, sometimes the sedative works so well, that they are almost there when the shot is given,,,,,, i feel there was no pain for my fur baby, but i never get over the loss