Abstract
Recent studies of peripheral vascular diseases have brought out the importance of differentiating the element of spasm from that of organic occlusion. Vasoconstriction can be demonstrated in the extremities of most individuals with normal blood vessels by measuring the surface temperatures. This action is present in varying amounts depending on the interplay of environmental conditions and the nervous mechanism. It possesses a definite gradient 1 so that it usually begins about the knee and progressively increases distally. Consequently the toes are normally the coldest parts of the lower extremity. These surface temperature differences can under certain conditions be made to disappear. In a series of 22 individuals with normal vessels it was found that this took place when the lumbar sympathetic fibres were paralyzed by spinal anesthesia. All surface temperatures of the extremities came to approximately the same level, with a variation of ±1.7°C. from the mean. This evidently represents a condition of physiological vasodilatation in the vessels of the extremities and we have called it “the normal vasodilatation level.” Its importance consists in that it permits an accurate estimate of the degree of spasm in any given case of vascular disease. The failure to react to the normal level in the latter signifies the presence of organic occlusion, the degree of which is measured by subtracting the maximum temperature achieved from the normal vasodilatation level. Having established the response to known regional sympathetic paralysis, we now report the effect of certain general anesthetics upon the vasoconstrictor gradient in order to simplify if possible the methods for gaining this information.
We have found that nitrous oxide-oxygen, ether, and tribromethyl alcohol individually in anesthetic doses will completely obliterate the vasoconstrictor gradient.
Get full access to this article
View all access options for this article.