mam tumor removal is a catheter needed?

Question
hello
my hairless rat, lily is going in next week to get a mammary tumor removed.  while going over the estimate for her procedure i was surprised to see that the vet wanted to use a catheter on her.  they informed me that it was in case of an emergency so that they could quickly give her pain meds.  is this really needed?  i told them not to give her a catheter unless there is an emergency.  am i doing the right thing?  your thoughts would be GREATLY appreciated?  thank you for your time.

Answer
Hmmm.....I am curious as to what they are charging you for this.  All they need to do is an injection of a narcotic pain medication and it hits rats very fast due to their fast metabolic rate.  I wonder the credentials on this vet?  Can you go private and let me know the name of the vet?

I think your probably getting a bunch of BS to be honest.