The Meaning of Bier's Spots.

Abstract

By vital staining with highly diffusible dyes we have found that sudden reductions of the blood volume lead to readjustments whereby the organs essential to the maintenance of life and to recovery continue to be well served by the circulation but at the expense of unessential ones, both visceral and peripheral. 1 The animals studied were white cats, rabbits and rats. The heart and lungs, the alimentary tract throughout its length (inclusive of the tongue and the gall bladder), the liver, pancreas, red bone marrow, and the respiratory muscles suffer practically no deprivation, even when the depletion has been pushed so far as to endanger life; whereas the skin and the voluntary muscles in general, the omentum, fat depots and urinary bladder are greatly neglected. One would expect the effective circulation through the spleen to cease, as does indeed happen. All the other neglected organs develop an ischemic patching except the bladder, which suffers as a whole. That in the skin resembles the so-called Bier's spots, blanchings noted in engorged human skin deprived of circulation. Our further work indicates that it is identical therewith.

Bier's spots appear gradually and enlarge by peripheral extension and coalescence. The ischemic patching of animals also develops gradually in skin from which the blood supply has been not quite all cut off; and the patches appear and spread as do Bier's spots. These latter are pallid, irregular, sharply outlined blotches on a congested skin, while the ischemic patches occur as similar areas devoid of stain, though scattered through a tissue which becomes well colored despite the reduced circulation. These differences are incidental to the differing methods of demonstration. Bier's spots are far more frequent where gravity or other influences act to empty the vessels in stasis than where they remain full. The patching in animals is also favored by these influences. Bier's blanchings develop far more frequently in the “red spots” which are still fed by a trickle of arterial blood from the marrow collaterals than where the skin is violet with stagnant blood. The combination of nearly empty vessels and a slight, inadequate blood flow is precisely that which leads to the ischemic patching of animals.