I keep my IV bags warm in an ice chest with my clean towels that has a heating pad in the bottom... if u dont have a plug near you... get an AC inverter for your car. IV fluids absorb faster and keep circulation smooth when they are at body temp. If your adding Dex SP or Solu Delta Cortef into your bag for shock therapy, that will also absorb faster if the fluids are warmed.

The point of IV Fluids is not to change the core temp of the dog... they are meant to replace the fluids the dog lost as rapidly as possible.