The Effect of Local Cooling on the Filtration and Absorption of Fluid in the Human Forearm

Abstract

Studies relating to the effects of cold on the permeability of human capillaries to protein and fluid have assumed practical importance in recent years because of current interest in refrigeration anesthesia and cryotherapy, as well as because of the casualties caused by exposure to cold during the recent war. Clinical (1) and experimental (2, 3) studies have shown that true frostbite increases the permeability of the capillary wall to both protein and fluid, but less is known quantitatively concerning the immediate effects of temperatures not sufficiently low to freeze the tissues but still injurious enough to produce serious lesions such as "immersion foot" (4).Lewis showed (5) that immersing the hands in water at various temperatures produced least change in their volume in the range from 150 to 20°C. At 100 C. or less, and at 25°C. or more, their volume increased. After prolonged immersion at 50 C., aspirated edema fluid contained approximately 3 per cent protein. These results suggested strongly that capillary permeability was increased by moderate cold but were not conclusive because the observed changes occurred while venous pressure was elevated and because changes in vascular volume could not be entirely excluded. At about the same time Lange (6) came to the opposite conclusion, viz. that the permeability of cutaneous capillaries in man and the rabbit is decreased by cold because the appearance in the skin of intravenously injected fluorescein was delayed at a temperature of 10°C. However, the rapid diffusibility of this dye makes it a very uncertain indicator of capillary permeability; it seems more likely that reduced blood flow, not decreased permeability, was responsible for the observed delay in staining of the skin. To obtain more quantitative information, the pressure plethysmograph of Landis and Gibbon (7) was used to measure changes in the volume of extravascular fluid in the forearm during exposure to external temperatures ranging from 44.50 to 4.50 C. It was found that moderate cooling (a) increased the extravascular volume of the forearm even when venous pressure was normal, (b) decreased the rate of filtration produced by a given increase of venous pressure and (c) decreased the rate at which extravascular fluid was reabsorbed. The evidence is consistent with the view that the human capillary wall becomes increasingly permeable to protein and fluid as environmental temperature falls below 250 C., but it also appears that other factors influence the rate at which edema develops during exposure to cold. METHODSThe pressure plethysmograph of Landis and Gibbon (7, 8) was used throughout. The particular advantage of this method is that the volume of a segment of forearm can be measured very precisely while it is exposed intermittently for brief periods to an external pressure of 200 mm. Hg. This pressure is sufficient to collapse the blood vessels and thus to exclude almost completely the large and unpredictable changes in volume which are caused by vasodilatation or vasoconstriction. By excludi...

Capillary Filtration Coefficient in the Extremities of Man in High Environmental Temperatures

“…Krogh et al (16) used the pressure plethysmograph to circumvent this objection; it theoretically determines the volume of the segment after collapse of all vascular components. Although a counterpressure of 55 cm water was at first thought to be sufficient to empty the vessels in a limb in which arterial inflow had been stopped, Landis and Gibbon (17) and Brown et al (1) found it necessary to increase counterpressure to 200 mm Hg. The technique has proved to be relatively satisfactory and has provided consistent and useful data (18).…”

“…1, upper diagram) are interconnected and applied around the part, with arrangements to assure connection of the lower strips to the skin. 1 For each calibration, the upper set of copper strips is short circuited to the same potential; this effectively moves the charges iThe materials from which this calibrating system was built were generously supplied by the Remco Tape Products Company of North Hollywood, California. from a corresponding area of skin through 1 mm to the upper level.…”

“…Investigators have tried to separate the effects of local heating, induced by immersing the extremity in warm water, from thermally induced reflex vasodUation. The capillary filtration coefficient is at a minimum when the limb is immersed in water at 14 to 15°C, and either decrease or increase of local temperature increases the capillary filtration coefficient (1,17,18). On the other hand, the hyperemia induced by reflex heating does not change the capillary filtration coefficient (18).…”

Transcapillary fluid movement in human calf after drinking hypertonic saline

“…After three or four measurements, however, the decrease in each measurement became constant, ranging from 0 5 to 1-5 ml. This amount gave the volume of interstitial fluid which was pressed out of the calf due to the com-732 TRANSCAPILLARY FLUID MOVEMENT pression during each measurement (Brown, Wise & Wheeler, 1947;Landis & Pappenheimer, 1964). This volume was obtained in each subject and used for the correction, as adopted by Brown et al (1947), to evaluate the actual change in reduced calf volume due to the ingestion of hypertonic saline.…”

The Loss of Fluid and Protein From the Blood During a Systemic Rise of Venous Pressure Produced by Repeated Valsalva Maneuvers in Man1

“…It is well known that protein-poor fluid moves from the vascular to the extravascular space during venous congestion of the forearm or lower extremity (1)(2)(3)(4)(5) and during a more generalized increase of venous pressure such as is induced by quiet standing (6,7) or by pressure breathing (8,9). No quantitative comparison has been made, however, between local and generalized congestion as to the quantity and duration of capillary filtration per unit increase of venous pressure.…”