Studies on Gangrene Following Cold Injury. Iii. Edema Following Cold Injury: Its Magnitude and the Composition and Sources of Edema Fluid 1

1947

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It has been reported in a previous communication (1) that increased leakage of fluid from capillaries is an invariable consequence of cold injury in rabbits' ears and feet. Although stasis in the true-capillaries was observed to occur in ears about 10 minutes after injury, it could be delayed by several procedures (2). The delayed appearance of stasis in the treated ears, as well as the invariable late occurrence of stasis at the junction between the normal and frostbitten regions of an ear, suggest that distortion of the tissues, resulting from the massive edema, may close true capillaries and produce stasis. The effect of capillary closure in limiting the exchanges between the blood stream and the cells is an important one.The similarity between the vascular lesion in frostbite and in burns is obvious and has been pointed out previously by others (3). Glenn (4) has recently reviewed the development of the treatment of burns by means of external pressure and by means of non-elastic, non-distensible dressings. Whether the good results of these forms of treatment depend upon "the control of capillary leakage" as suggested by Glenn or whether the benefit may derive from prevention of the mechanical distortion produced by swelling has not been determined. However, measures which aim at the control of either of these consequences of heat injury find equal justification for their use in the treatment of frostbite.Two different types of dressings are available for the mechanical control of fluid loss following injury: I (a) Closed plaster casts were used by Glenn, Gilbert, and Drinker (5) for the treatment of experimental burns. The rationale of this procedure has been described by Glenn (4): "As plasma es- capes from the dilated hyperpermeable capillaries, the extravascular tissue fluid pressure quickly builds up against the rigid encasement to exactly equal the pressure attempting to push fluid out of the capillaries." Such dressings should be skintight, non-elastic and non-distensible. In order to be maximally effective they should be applied before swelling of the injured part has taken place, and they must be applied in such a way that the distal part of the limb is encased in the dressing.(b) External pressure to control fluid loss, as used by Allen and Koch (6) and others, is applied in the form of a pressure dressing of elastic material. A layer of padding separates the tissue from the elastic bandage and serves to equalize the pressures within the dressing. This form of dressing offers no obvious advantages over rigid casts for immediate treatment of frostbite in the period before swelling has begun. METHODSStandard cold injury. Injury was produced by immersing the hind feet of rabbits in a mixture of water, ethylene glycol, and alcohol cooled by the addition of solid carbon dioxide. The times of exposure and the temperatures used included those from 15 to 60 minutes at -15°C. and 2 and 3 minutes at -550 C. Details of standardization of cold injury produced by this means are given in the first paper of this s...

Section: Discussionmentioning

confidence: 55%

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

Crismon¹,

1947

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“…The delayed penetration of fluorescein into frostbitten regions also seems difficult to explain upon the basis of Lange's second suggestion, decreased filtration pressure, since this would have to coincide with the appearance of massive edema and the rise of subcutaneous tissue pressure to levels as high as 25 cm. of water (7).…”

Section: Discussionmentioning

confidence: 99%

Studies on Gangrene Following Cold Injury. V. The Use of Fluorescein as an Indicator of Local Blood Flow: Fluorescein Tests in Experimental Frostbite 1

Crismon

1947

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The application of the fluorescein test to the study of frostbite has been described recently by Lange and Boyd (1). In the course of studies of experimental frostbite carried on in this laboratory, certain of the results obtained with the fluorescein test have been difficult to explaih on the basis of interpretations suggested by the proposers of the method. Two groups of experiments were undertaken in order to study certain aspects of fluorescein exchange not already reported in the literature. The first group of experiments consisted of studies on normal rabbits of skin fluorescence and fluorescein distribution in body fluids: these have been presented previously (2). The present paper reports the second group of studies carried out on normal rabbits and on rabbits subjected to severe cold injury. METHODThe techniques employed in the fluorescein test, the measurement of skin fluorescence after the injection of fluorescein, and the analysis of body fluids for fluorescein were described previously (2). Skin cence was detectable in hair-free areas of the skin within a few seconds after the beginning of injection. The intensity of color became maximal in about 15 minutes. The decline of intensity was, at first, rapid and then progressively more gradual over a period of 2 to, 2Y2 hours.In the rabbit ear, the regions which glowed most intensely were those relatively free of large blood vessels. The larger blood vessels stood out as dark streaks which could be obliterated by prescure with a glass slide. The areas rendered ischemic by pressure showed no decrease of fluorescence. Fuorescence in frostbitten ears of rabbitsThe influence of injury by frostbite upon the distribution of fluorescein after intravenous injection was studied on rabbits' ears. Frostbite was produced by immersing the distal 3 to 4 cm. of the ears in a freezing mixture consisting of alcohol, ethylene glycol, and water with sufficient solid carbon dioxide added to bring the temperature between -520 C. and -70°C. The details of the method of producing standard cold injury and the general course of changes following such injuries have been described in previous reports (3,4).Abnormalities in the distribution of fluorescein in the frostbitten portion of rabbits' ears included decreased rate of entrance of dye, slower rate of removal, and lower maximum intensity of fluorescence than was observed in the normal ear. Observations made at varying intervals after injury showed that the local changes, which were responsible for the abnormalities of fluorescein distribution, undergo modification with time. The photographs in Figure 1 illustrate the delayed penetration and exit of the dye as well as the differences in results of identical tests made immediately after inquiry and repeated 268

“…Thus, in spite of the fact that the true capillaries may lose large amounts of fluid up to the time that stasis is complete, the later loss of fluid into the extravascular compartment must occur mainly as the result of the high filtration pressure within the "thoroughfare channels." The measurement of changes in volume and subcutaneous tissue pressure in frostbitten feet of rabbits (23) showed that maximum volume is reached in about 2 hours after injury and that the pressure of fluid in the interstitial compartment reaches its maximum of 25 to 30 cm. of water at about the same time.…”

Section: Observationsmentioning

confidence: 99%

“…In the period between thawing and the attainment of maximum swelling a new filtration equilibrium is established at high levels of capillary pressure, interstitial fluid pressure, and rate of fluid exchange. That fluid continues to be lost from the blood in the injured regions at rates which overwhelm the local routes of removal is illustrated by 2 observations: (a) the movement of edema fluid in the subcutaneous tissues far into the uninjured regions from the area injured by cold (23); and (b) the rapid lymph flow from the injured region as demonstrated with the aid of dyes.…”

Section: Observationsmentioning

confidence: 99%

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

Crismon

1947

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Indirect evidence, based upon measurements of skin temperature and observations of skin color in the feet and ears of rabbits subjected to severe cold injury, indicates that complete arrest of blood flow does not occur until more than 50 hours after injury (1). Tests of the local circulation in coldinjured regions with intravenously injected fluorescein show that the exchange of this dye between blood and interstitial fluid is impaired during the interval when the minute volume blood flow is greater than that in comparable uninjured regions (2, 3). Early arrest of blood flow in regions injured by cold has been variously ascribed to "conglutination" of red-cells (4), to capillary stasis (5), and to intravascular clotting (2). While all of the above phenomena may be observed in frostbitten tissues, none has provided an explanation of the nature of local changes in blood flow adequate to account for the maintenance of high peripheral tissue temperature at a time following cold injury when exchanges of oxygen, nutrients, and metabolites appear to be impaired.This report presents the results of microscopic study of blood flow in the small vessels of the ears of rabbits during the first hour after freezing. Blood flow was also studied in the ears of animals which were treated by rapid thawing of the ear in warm water and by procaine block of the stellate ganglion on the injured side. METHODSCold injury was produced by immersing the distal one-half to one-third of the ear for 60 seconds in a mixture of water, ethylene glycol, and alcohol cooled to -550 C. with solid carbon dioxide. Details of this method for the production of controlled cold injury and the characteristic effects on the tissues are given elsewhere (6).X The work described in this paper was done under a contract, recommended by the Committee on Medical Research, between the Office of Scientific Research and Development and Stanford University.Both normal and frostbitten ears of a uniform strain of New Zealand white rabbits were observed through a binocular dissecting microscope having 9X oculars and 4.8X objectives. The light sources was a 100-watt Spencer microscope lamp from which the light was conducted to the ear by means of a polished rod of %-inch methyl methacrylate (Lucite) 2 feet long. The rod was tapered to a cone having a rounded tip 7 mm. in diameter. The distal 8 inches of rod were bent into a curve which presented the brilliantly illuminated tip at a right angle to the original path of light. WiAh the rod in an adjustable clamp, its flattened end in contact with the blue glass of the microscope lamp, the ear was placed under the objectives of the microscope in direct contact with the methacrylate rod. Liquid petrolatum was applied to the shaved ear in order to clear the keratinized epithelium. Photographic recording of the changes observed proved to be unsatisfactory because of the thickness of tissue and the changing optical plane. OBSERVATIONSBlood flow in the capillaries of the normal ear.Movement of blood could not be seen in the larger...