Responses of blood vessels in the resting hand and forearm to various stimuli

With the development of accurate plethysmographic methods, considerable knowledge has been gained regarding blood flow in, and vasomotor reactions of, blood vessels in the hand. However, it has been demonstrated that alterations in blood flow in the hand apparently do not parallel vascular responses elsewhere in the body. For example, Grant and Pearson¹ and, more recently, Kunkel, Stead, and Weiss² have reported that adrenalin, although it produces a marked decrease in blood flow through the hand, causes an increase in flow through the forearm. Likewise, Abramson, Zazeela, and Oppenheimer³ have observed that smoking causes a significant reduction in flow in the hand and practically no change in the forearm. Since blood flow measurements in the hand have been used qualitatively to gauge changes in systemic flow during the state of shock⁴ and during the inhalation of various gases,⁵ it becomes important to ascertain under what conditions, if any, such assumptions are valid, and whether more reliable information concerning the peripheral circulation may not be obtained from studying other vascular beds.The present study deals with a comparison of the reactions of blood vessels in the hand and forearm to different types of stimuli. An attempt is made (1) to ascertain the relationship of vascular responses in these two areas to changes in the systemic circulation, (2) to evaluate and clarify the mechanisms responsible for the limb-volume changes produced by these stimuli, and (3) to ascertain whether or not the control of blood flow through the forearm differs from that through the hand.