Which of the following is NOT an appropriate step to take when treating cold injury to the feet?

Using a space heater to warm the feet is not an appropriate step when treating cold injuries. This method can pose several risks, particularly the chance of burns or further tissue damage. Direct heat from a space heater can be too intense and may not provide a controlled warming environment, which is essential for individuals suffering from cold injuries.

In treating cold injuries, it is crucial to warm the affected areas gradually and evenly to avoid complications like rewarming shock or increased vasodilation, which can lead to further injury.

Gently warming the feet in the armpits is effective because it allows for gradual and controlled heat transfer from the body. Wrapping the feet in dry, warm coverings helps retain some heat while protecting them from further exposure to the cold. Using a warm water bath is another appropriate method, as it provides a consistent and gradual warming environment that can help to restore normal temperature safely.