Wilderness and Rescue Medicine 7th Edition Jeffrey Isaac, PA-C and David E. Johnson, MD

Wilderness and Rescue Medicine 148

Field rewarming of deep frostbite is a high-risk treatment but should be considered if evacuation will be dangerous or prolonged. You must have the necessary shelter and equipment and be able to prevent refreezing. Do not rewarm in the field if use of the extremity will be necessary for sur- vival and evacuation. Set up a secure shelter, and be sure your patient is warm, dry, well fed, and hydrated.

Premedicate with an anti-inflammatory drug like ibuprofen (800 mg) taken by mouth. This reduces pain and inflammation and helps pre- vent blood clots in the rewarmed tissue. Giving stronger pain medication may be necessary dur- ing the process. Rewarming is performed by immersing the fro- zen extremity in water warmed to between 37° and 39°C. The water should feel warm to normal skin, but not uncomfortable. Keep adding warm water to the pot to maintain the temperature as the thawing process continues. Avoid direct expo- sure to dry heat like a camp fire. Rewarmed tissue will appear red and blue and feel soft to the touch. Blisters may form early and be clear, red, or blue depending on the fluid inside. Once the part is rewarmed, it is vital to protect it from trauma. This means no use of the digit or extremity. Sterile dressings should be placed over and between digits, and the extremity should be bandaged and splinted to restrict movement. Absolutely never allow the part to refreeze. If the feet are affected, a carry-out or air evacuation is necessary.

In deep frostbite the skin and underlying tissues are frozen solid. The area is white or bluish and hard to the touch.

Monitor frequently to ensure that splints or bandages do not constrict circulation as swell- ing develops. If possible, keep the part elevated. Continue regular doses of ibuprofen at a mini- mum of 12 mg/kg divided twice daily. This may be increased to a maximum of 2,400 mg divided four times daily if the patient is experiencing pain. If you have it, cover the area with aloe vera gel or ointment, which has been shown to have both anti-inflammatory and antibacterial properties.

The foot on the right was frozen, rewarmed, and frozen again before hospital admission. The left foot remained frozen until controlled rewarming was performed.