Cold injuries include frostbite and frostnip. Frostbite is the term for damage to skin and other tissues caused by freezing. Frostnip is a milder form of cold injury.
Description
In North America, frostbite is largely confined to Alaska, Canada, and the northern states. However, it can occur whenever people are exposed to sustained cold temperatures without proper protection. Recent years have witnessed a substantial decline in the number of cold injury cases, probably for several reasons, including better winter clothing and footwear and greater public understanding of how to avoid cold-weather dangers. At the same time, the nature of the at-risk population has changed. Increased numbers of homeless people have made frostbite an urban as well as a rural public health concern. The growing popularity of outdoor winter activities has also expanded the at-risk population.
Frostbite
Emergency medical help should always be summoned whenever frostbite is suspected. While waiting for help to arrive, one should, if possible, remove wet or tight clothing and put on dry, loose clothing or wraps. A splint and padding are used to protect an injured area. Rubbing an injured area with snow or anything else is dangerous. The key to prehospital treatment is to avoid partial thawing and refreezing, which releases more
inflammatory mediators and makes an injury substantially worse. For this reason, the affected part must be kept away from heat sources such as campfires and car heaters. Experts advise rewarming in the field only when emergency help will take more than two hours to arrive and refreezing can be prevented.
Because the outcome of a frostbite injury cannot be initially predicted, all hospital treatment follows the same protocol. Treatment begins by rewarming the affected part for 15–30 minutes in water at a temperature of 104–108°F (40–42.2°C). This rapid rewarming halts ice crystal formation and dilates narrowed blood vessels. Aloe vera (which acts against inflammatory mediators) is applied to the affected part, which is then splinted, elevated, and wrapped in a dressing. Depending on the extent of injury, blisters may be debrided (cleaned by removing foreign material) or simply covered with aloe vera. A tetanus shot and possibly penicillin are used to prevent infection, and the injured person is given ibuprofen to combat inflammation. Narcotics are needed in most cases to reduce the excruciating pain that occurs as sensation returns during rewarming. Except when injury is minimal, treatment generally requires a hospital stay of several days, during which hydrotherapy and physical therapy are used to restore health to the affected body parts. Experts recommend a cautious approach to tissue removal, and advise that 22–45 days must pass before a decision on amputation can safely be made.
Alternative practitioners suggest several kinds of treatment to speedrecovery from frostbite after leaving a hospital. Bathing the affected part in warm water or using contrast hydrotherapy may help enhance circulation. Contrast hydrotherapy involves a series of hot and cold water applications. A hot compress (as hot as the patient can stand) is applied to the affected area for three minutes followed by an ice cold compress for 30 seconds. These applications are repeated three times each, ending with the cold compress. Nutritional therapy to promote tissue growth in damaged areas may also be helpful. Homeopathic and botanical therapies may also assist recovery from frostbite. Homeopathic Hypericum (Hypericum perforatum) is recommended when nerve endings are affected (especially in the fingers and toes) and Arnica (Arnica montana) is prescribed for shock. Cayenne pepper (Capsicum frutescens) can enhance circulation and relieve pain. Drinking hot ginger (Zingiber officinale) tea also aids circulation. Other possible approaches include acupuncture to avoid permanent nerve damage and oxygen therapy.
Frostnip
Frostnipped fingers are helped by blowing warm air on them or holding them under one's armpits. Other frostnipped areas can be covered with warm hands. The injured areas should never be rubbed.
Diagnosis
Frostbite diagnosis relies on a physical examination and may also include conventional radiography (x rays), angiography (x-ray examination of the blood vessels using an injected dye to provide contrast), thermography (use of a heat-sensitive device for measuring blood flow), and other techniques for predicting the course of injury and identifying tissue that requires surgical removal. During the initial treatment period, however, a physician cannot judge how a case will progress. Diagnostic tests only become useful between three and five days after rewarming, once the blood vessels have stabilized.
Prognosis
The rapid rewarming approach to frostbite treatment, pioneered in the 1980s, has proved to be much more effective than older methods in preventing tissue loss and amputation. A study of 56 first-, second-, and third- degree frostbite patients treated with rapid rewarming in 1982–85 found that 68% recovered without tissue loss, 25% experienced some tissue loss, and only 7% needed amputation. In a comparison group of 98 patients, treatment using older methods resulted in a tissue loss rate of 35% and an amputation rate of nearly 33%. Although the comparison group included a higher proportion of second- and third-degree cases, the difference in treatment results was determined to be statistically significant.
The extreme throbbing pain that many frostbite sufferers endure for days or weeks after rewarming is not the only prolonged symptom of frostbite. During the first weeks or months after a cold injury, people often experience tingling, a burning sensation, or a sensation resembling shocks from an electric current. Other possible consequences of frostbite include skin-color changes, nail deformation or loss, joint stiffness and pain, hyperhidrosis (excessive sweating), and heightened sensitivity to cold. For everyone, a degree of sensory loss lasting at least four years—and sometimes a lifetime—is inevitable.
Health care team roles
The head of most health care teams is a physician. A physician determines a plan for treatment, provides guidance, assigns tasks for other members of the team, and monitors progress. Paramedics or other persons renderingfirst aid are also members of the team by providing immediate or early assistance to persons with frostbite or frostnip. Nurses may provide treatment alongside physicians. Physical therapists may become involved with rehabilitation of serious cases of frostbite. Occasionally, surgeons are called upon to amputate (remove) portions of bodies that have become too severely damaged to recover from frostbite.
Prevention
With appropriate knowledge and precautions, frostbite can be prevented even in the coldest and most challenging environments. Appropriate clothing and footwear are essential. To prevent heat loss and keep blood circulating properly, clothing should be worn loosely and in layers. Covering the hands, feet, and head is also crucial for preventing heat loss. Outer garments need to be wind and water resistant, and wet clothing and footwear must be removed and replaced as quickly as possible. Alcohol and drugs should be avoided because of their harmful effects on judgment and reasoning. Experts also warn against alcohol use and smoking in the cold because of the circulatory changes they produce. Paying close attention to weather reports before venturing outdoors and avoiding unnecessary risks such as driving in isolated areas during a blizzard are also important.
BOOKS
McCauley, Robert L., et al. "Frostbite and Other Cold-Induced Injuries." In Wilderness Medicine: Management of Wilderness and Environmental Emergencies. edited by Paul S. Auerbach. St. Louis: Mosby, 1995.
Petty, Kevin J. "Hypothermia." In Harrison's Principles of Internal Medicine, 14th ed. edited by Anthony S. Fauci et al. New York, McGraw Hill, 1998.
Yoder, Ernest L. "Disorders due to heat and cold." In Cecil Textbook of Medicine, 21st ed. edited by Goldman, Lee, Bennett, J. Claude. Philadelphia, Saunders, 2000.
PERIODICALS
Graham, C.A., and Stevenson, J. "Frozen chips: an unusual cause of severe frostbite injury." British Journal of Sports Medicine (October 2000): 382-383.
Hall, Christine B. Cold Hurts: Frostbite, Frostnip, and Immersion Foot. Anchorage, AL: University of Alaska Sea Grant, 1995.
Hamlet, M.P. "Frostbite." International Journal of Circumpolar Health 59 (2000): 1-130.
ORGANIZATIONS
Rocky Mountain Survival Group. P. O. Box 2572; Dillon, Colorado 80435. megraven@sprintmail.com.
