Remember that hypothermia gives you time to plan out a course of action. Once you begin, changes will be fast and furious. Have all necessary equipment ready before you start. Correct acidosis cautiously - as the patient rewarms, he will revert to normal spontaneously. Too much correction will result in boomerang alkalosis.
Pneumonia is the most common complication, followed by renal failure.
G.I. bleeding is also common. Consider antibiotics, Cimetidene. External rewarming methods such as warm gas inhalation, warm IV fluids, hot enemas, etc. have proved ineffective when used alone, but can be used in conjucntion with other methods. Cardiopulmonary Bypass and Femorla A-V Shunt can also be used if available. Bangs, Cameron C., Early Recognition and Treatment of Chronic Cold Injuries, unpublished paper, date unknown.