Studies on Gangrene Following Cold Injury. Vii. Treatment of Cold Injury by Means of Immediate Rapid Warming 1

Abstract

Hind limbs of dogs were frozen with solid CO2 and one leg was thawed at 42°C. for comparison with the other thawed at 20 to 120 C. One frostbitten ear of rabbits was thawed at 380 C. and the other at 2°C. In neither case was any essential difference reported between the rapidly and slowly thawed extremities, although the frostbitten legs were observed only for 18 hours. They reported that "if anything, the ears that were thawed in ice water showed a trace more gangrene."Ariev (1) has reported the results of several series of experiments which were designed to compare the effect of slow and rapid warming of frozen ears and feet of rabbits. After freezing both ears of rabbits with ethyl chloride, one ear was warmed with hot compresses wet in water at 400 to 450 C. The frostbitten part of the slowlywarmed ear was ultimately lost in 5 animals while the rapidly-warmed ear showed only fibrosis in the distal part. Both feet of rabbits were frozen with ethyl chloride to the tibio-tarsal joint. One foot was then rapidly thawed by means of the application of compresses wet with water at 350 to 400 C. while the other was thawed in air. In the rapidly warmed foot, gangrene "only touched the most distal parts of the toes," while in the opposite foot "total gangrene spread over the entire region subjected to freezing."The experiments reported here were carried out in order to determine the effectiveness of immediate rapid warming in preventing the occurrence of gangrene following controlled cold injury. The effect of rapid warming on local blood flow in frostbitten ears and feet following thawing f has been examined by means of fluorescein and by s measurement of skin temperature. METHODS aThe method used for the production of controlled cold injury has been described previously (6). In this series of experiments, rabbit ears were immersed at -550 C. for 1, 112 or 2 minutes; rabbit feet were immersed at -55' 476

Studies on Gangrene Following Cold Injury: Vi. Capillary Blood Flow After Cold Injury, the Effects of Rapid Warming, and Sympathetic Block 1

“…Frostbite produced in the ears of rabbits by immersing the part in the freezing mixture at -550 C. for 1 minute resulted invariably in the development of gangrene and the ultimate loss of all of the ear up to the line of immersion, if the ears were allowed to thaw (in air at 250 C.) without treatment. In confirmation of the work of Ariev (7), we have found that the same exposure to cold followed by immediate warming of the ear in water at + 420 C. for 2 minutes prevents the development of gangrene and loss of the injured tissue (8). In spite of the favorable end result of rapid thawing, the tissues underwent a series of changes which were grossly similar to the pregangrenous changes in the frozen, untreated ears.…”

Studies on Gangrene Following Cold Injury. Viii. The Use of Casts and Pressure Dressings in the Treatment of Severe Frostbite 1

“…The results of treatment of cold injury by early mechanical control of the edema, by immediate rapid warming (12), and by the use of heparin as described by Lange and Boyd (14) all confirm the opinion of Bigelow (15) that stasis is not necessarily an irreversible process. The interruption of the transition from temporary arrest of blood flow by stasis to permanent arrest ky thrombosis may be accomplished by a variety of means.…”

“…In contrast to the complete loss from gangrene of the part subjected to injury when no treatment is used, there is a striking reduction in the extent of gangrene following the application of a non-distensible dressing before swelling has occurred or the use of an elastic pressure dressing after swelling is maximal. In general, the amount of tissue saved by the use of measures designed to control swelling are somewhat smaller than the proportion saved by immediate, rapid warming' (12 The success or failure of treatment of cold injury by the application of casts or pressure dressings depended to an important degree upon the manner of application of the dressing and also' upon the nature of the material used for padding. Unequal distribution of pressure, especially over bony prominences, contributed greatly to the development of gangrene.…”

“…To the extent that edema following severe injury by cold (1, 2) may be responsible for some of the changes leading to gangrene, the acceleration of lymph drainage of edematous areas should be helpful in reversing the processes which lead to the development of gangrene. Even in circumstances where gangrene does not occur, the swelling has been shown to lead to induration and later formation of collagenous scars in the subcutaneous tissues (12). Past experience has shown that most cases of accidental injury by cold, especially in military operations, do not receive treatment until a considerable time after exposure, and edema is then usually well advanced.…”

The Problem of Frostbite in Civilian Medical Practice

“…During actual freezing, the tissue becomes opaque as observed by transillumination. 11 Upon thawing, appearance is normal for a short time. Edema and rupture of small vessels is then observed, particularly of small venules.…”