What type of blanket contains coils filled with a cooling solution to reduce high body temperature?

The most fitting choice for a blanket that contains coils filled with a cooling solution to reduce high body temperature is identified as a hypothermia blanket. These blankets are specifically designed to aid in the management of body temperature, particularly in cases where an individual is experiencing overheating or needs to be cooled down for medical reasons. Hypothermia blankets often use a controlled cooling system to help bring down the body temperature in a safe and effective manner.

In contrast, thermal blankets serve more to retain body heat and keep individuals warm, whereas cooling mats typically provide a surface for cooling but do not have the sophisticated cooling mechanisms that hypothermia blankets do. Insulating covers are generally used to maintain temperature rather than lower it, so they wouldn't fit the description of a device intended for cooling the body. Thus, the hypothermia blanket is the most accurate choice due to its design and purpose in clinical settings.