Human Muscle and Skin Blood Flow

Abstract

The continually increasing number of substances intended to improve peripheral blood flow now enjoys great theoretical and clinical interest. Human trials are unavoidable to evaluate their effect, since the physiology of peripheral blood flow in animals and humans may exhibit considerable differences. In the light of our present knowledge, it is furthermore necessary to measure the Muscle and skin blood flow separately. The physiological responses of these two vascular regions show great divergence-in some cases even opposite effects are seen. This difference is also of clinical importance, since some disturbances of peripheral circulation are manifested predominantly in the skin, particularly in the skin of the acra, while with others disturbed muscle flow (claudication) comes to the fore (compare Bruck et al. (14) ) .This demand for separate recording of muscle and skin flow has been satisfied so far by only a few methods. Brodie and Russell's (12) venous occlusion plethysmography, including the numerous modern variations, allows of dependable measurement of the total arterial inflow to a given section of the limb, but does not allow of any differentiation between skin and muscle flow.The assumption of Grant and Pearson (28), that changes in total flow of muscular parts of a limb (forearm, calf) predominantly represent changes in muscle flow, is the case only when no significant change in skin flow takes place. Here the method has resulted in valuable insight into the physiology of human muscle blood flow (2). If, however, this condition is not fulfilled, erroneous conclusions are possible. For instance, the great increase in total flow of the forearm and calf during indirect heating of the body is exclusively an increase in skin flow, while, if anything the muscle flow diminishes (Barcroft, Bock, Hensel and Kitchin-not yet published). Even adrenaline electrophoresis to eliminate skin blood flow seems not always to result in success, as demonstrated particularly by the experiments with body heating. Any statement therefore regarding what should be related to the muscle is in the last instance possible only by checking with other methods.Inasfar as they are applicable to the human being, thermal methods have been suitable only to evaluate skin blood flow. The simple thermo-electric recording of skin temperature is restricted in its application to evaluate skin blood flow and is open to much criticism (1, 6, 10, 20, 35-37, 43, 49, 62, 65, 67, 73). In order to allow more exact determination of human skin blood flow, the flow calorimeter (35, 36) has recently been introduced.

Peripheral Circulation

“…Lastly, as smoking in these days is such a widespread habit that nicotine can be looked upon almost as a "normal" humoral factor, it may be justi fiably mentioned here that smoking a cigarette induces a presumably neuro genic vasoconstriction in the skin and a vasodilatation in the muscles, pre sumed to be caused by epinephrine released from the adrenals (373,403).…”

An Evaluation of the various Peripheral Dilators used in the Treatment of Intermittent Claudication

“…Ostwald (1950) states that“ vigorous stimulation of muscle circulation was observed” but gives no figures. Hensel and others (1955) in America, using the calorimetersende to measure muscle blood flow, state that in 8 of 10 healthy persons the blood flow increased up to 250 per cent of the resting value, and the increase lasted for 50 minutes when Perdilatol was infused intravenously for 10 minutes. In England, Riddel and others (1954) studied the effect of Perdilatol 5 mg. per kg.…”