As Grace said, it's probably a capillary. Not a thing to be worried about, but it sure can shake a person up to see that when it's not expected. I always loosen up the control on the IV bag before dispensing it into the kitty. Often the tubing will be sealed shut where the valve was off, and this could be why it seemed slow to you. I always warm the fluids to a comfortable temp. as well, so as not to send an already unwilling kitty flying away from the cold liquid! It works for me. Hoping to get more positive Puddy uppydates soon. Jan