STUDIES ON GANGRENE FOLLOWING COLD INJURY. I. A METHOD FOR PRODUCING GANGRENE BY MEANS OF CONTROLLED INJURY BY COLD 1

Abstract

Controlled cold injury (frostbite) of rabbit ears and feet was produced by immersion of the depilated part in a water-ethylene glycol-alcohol mixture cooled to the desired temp. by means of the addition of solid CO2. The immersion of ears of anesthetized rabbits in liquid at temps, ranging from[long dash]32[degree]C to[long dash]70[degree]C for periods of 1-10 mins. resulted in freezing of the ear, edema, gangrene and spontaneous amputation of the entire injured part of the ear. Immersion for 15-30 secs. at[long dash]55[degree]C resulted in loss of about 80% of the injured part of the ear. The effects of immersion of the hind feet of anesthetized rabbits in cold liquid varying from[long dash]15[degree]C to[long dash]55[degree]C for different lengths of time were detd. At[long dash]55[degree]C the extent of tissue loss could be increased by increasing the duration of exposure from 1-4 mins. At[long dash]15[degree]C the deep tissue temperature of a foot became equal to that of the bath in 15 mins. At this temp. the extent of tissue loss could also be increased by increasing the duration of exposure. When the time olf exposure was maintained constant at 3 mins. and the bath temp, varied from[long dash]15[degree]C to[long dash]45[degree]C, progressively greater loss of tissue was encountered with reduction of exposure temp. Precooling of feet for 30 mins. at about +2[degree]C increased the severity of injury following a subsequent exposure for 1 min. at[long dash]55[degree]C. Gangrene did not result from exposure for 1 hr. at[long dash]15[degree]C if freezing of the tissue did not occur. Gangrene resulting from cold injury was qualitatively identical in each case regardless of the time or temp. of exposure. Readily reproducible degrees of injury and amts. of tissue loss could be obtained by exposure at a given temp. for a given period of time.