Too warm fluid causes them to go ballistic as well as too cool fluid. It should be body temperature and tested the same way you test the temp of a baby's bottle - inner wrist.
You may have hit a nerve or the needle may have been jabbing the skin from the inside.
- I Love Lucy
To help reduce leakage, I always try to pinch the skin where the needle is at when I'm pulling the needle out or after I pull it out (depending on what the pig will let me do). It does help reduce the amount of leaking/bleeding, but I'll warn you now that pigs HATE being pinched, even the slightest little bit. I usually get more protesting screeches then than at any other point during the subq. Pulling up the skin to insert the needle is the runner-up.
Be super careful that you don't get your fluids too warm. Always squirt a little on your hand or arm to test before injecting. Cold fluids don't feel good, but too hot fluids would probably be like torture and likely cause tissue damage. Always err on the side of caution.
Also, ditto on what Josephine said about using a new needle for everything. Guinea pigs have very tough skin compared to other animals, so the sharper the needle, the better. Even just sticking it into the fluid bag to draw up the fluids dulls it a little IMO.
The inside of the arm (or wrist) is a good test point. Hands are very tolerant of heat and cannot judge temps as accurately.
If you've raised kids, you know to use the tender inside of your arm and never trust the hand for checking bath temps. I never used baby bottles but one always sprinkled some milk on the inside of the arm to ensure it was not too hot.
Yes, I do use a new needle each time, and at the vet tech's suggestion, I leave one needle in the bag that is used for drawing up the fluid -- then put a new needle on the syringe for giving the subcue.
Today's session went a whole lot better. I didn't warm the solution for very long at all (ran it for just a few seconds under the hot water faucet, turning it constantly...I thought it just felt tepid, but Sebastian seemed more a lot comfortable with it), and it went quickly. How do you know if you have the right temperature or not? Guinea pigs having a higher body temperature than we do, I guess I just assumed it needed to be pretty warm.
I really hate that I hurt Sebastian the other day. I had squirted the warmed solution on the inside of my arm and thought it felt nicely warm without being too hot, but he had an absolute fit with it, and then had those "hiccups" afterwards (God, that was quite a morning).
Well, with any luck at all, maybe he'll start drinking on his own again after the Prednisone has a chance to kick in. Hope so.