Final answer:
Forced air warming prevents hypothermia during surgery primarily by reducing radiant heat loss through convection, by warming the air around the patient's body to form an insulating layer and maintain steady core temperature.
Step-by-step explanation:
Forced air warming prevents hypothermia during surgery by reducing radiant heat loss. This method works through convection, which involves warming the air around the patient's body. This warm air forms a boundary layer over the skin, preventing heat loss via radiation. Unlike options such as increasing the metabolic rate, enhancing cutaneous vasodilation, or improving shivering response, which are physiological responses to cold, forced air warming provides an external method to maintain body temperature.
The mechanisms of heat loss - radiation, evaporation, conduction, and convection - play roles in how the body manages temperature. During surgery, due to anesthesia, patients lose the ability to regulate body temperature effectively, making them susceptible to hypothermia. By using forced air warming blankets, the body is insulated against cold environmental temperatures, thus directly reducing radiant heat loss and keeping the patient's core temperature steady.