Pulse registration as a means of evaluating peripheral vascular patency and vasomotor activity.

T IlE REGIS'RAlltN of the volume pulses from various pare of a limb has been found to he an accurate and simple method of demonstrating local vascular patches and clianges in blood vessel tones :. The method has the following advantages over others previously employed; particularly the measurement of skin temperature_ (1) The sensing pneumatic cuff of the device embraces the total cross section of the limb at each level examined, so that the resultant pulse trace reflects changes in the deep as well as the superficial arteries . (2) The cuff, are easily applied to aire level of the limb, from a digit upward, avoiding examination of the digits alone. where tones is subject to great spontaneous variations, and allowing also an appraisal of the circulation over the entire limb . t31 With this method . the reactivity of the part may he tested by direct heating, or cooling . Such a direct application of thermal changes is more efficient than indirect methods in inducing change, in tone, and more nearl' approximates the environmental stres_es from which the syrriptomtt of some patients arise The urethod Iias been used in differentiating functional from organic disease, an well as in evaluating the degree of spasm or the flexibility of the arterial systeur when permanent structural changr_s are present . The study has reinforced the concept that vascular tonus is the sum of all constrictive and vasodilatory influences. We have further been impressed by the universality (if the vasoconstrictive response to cold as an expression of both functional and organic arterial disease . METHOD Pulse Regislralion and Quantilation : This aspect of the method has been detailed in a former publication,' but it may be summarized here. The apparatus consists of a series of pneumatic cuffs, two of which may be connected simultaneously to the transducing unit (the Infraton Pulse Oseillograph d . A pressure of 30 mm . Hg is used in the pneumatic system. The transducing element is a differential capacitor; the output of which is fed into a direct writing Sanborn recorder . A paper speed of 25 mm . per second is used throughout . While simple inspection of the curves allows a good estimate of change in pulse configuration and an approximation of ampliurde and slope, a quantitative evaluation of these two factors is available . ']'his is made possible by calibration of the height of pulse defection for each cult application through a device that displaces a known volume of air in the pneumatic system . The degree of displacement of the recording pen is noted . With this calibration, the pulse trace can be expressed in two parameters . The first is mean pulse deflection (mean change in vohune in cubic millimeters during one pulse cycl(-). noted as 1) in the illustrations . In arriving at this value Lhe area under a pulse trace is measured by a planirneter . In this way the difference between a sustained and an acuminate pulse is taken into account . 'I 'he second parameter is the systolic slope (rate of systolic increase in volume of the pulse in cubic millimeters per se(ond), noted as 55 in the figures . The Iractions shtnvn in some of the figures dlrnote the attenuation of the recording used for the particular pulse trace icproduced . Induction of Vasodilatation and VasocoruUict,orc Patients were examined after resting from ten to thirty minutes in a morn in which the temperature was kept 1 )brained I'roni Medical F .leetronies Development Co., Long Island, New York .