Plethysmographic studies of peripheral blood flow in man

“…Hg. A similar pressure was found to be necessary for the dependent foot by Abramson et al (6). The apparent venous pressure was regularly found to be 30 to 40 mm.…”

Section: Details Of Construction and Use Of The Apparatussupporting

confidence: 63%

Heat Loss and Blood Flow of the Feet Under Hot and Cold Conditions

Love¹

1948

Journal of Applied Physiology

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A LTHOUGH THE IMPORTANCE of the extremities in thermo-regulation is well established little has been done to follow progressive changes in these areas during relatively long exposures to heat and cold. There are available the results of Burton (I) showing a gradual increase in finger blood flow during several days of exposure to heat and a gradual decrease during exposure to cold. In this same paper it is shown that the superficial veins of the forearm become fully dilated in the heat and fully constricted in the cold only after some time. There are also observations on the amount of convective and radiant heat loss from the hand which show that the proportion of heat lost by the different pathways can change during the course of exposure (2). The experiments to be reported here were designed to extend these relatively long-range observations. Measurements were limited to the foot and included the evaporative and non-evaporative heat loss, blood flow and skin temperature of subjects living in a controlled temperature room for periods up to two weeks. Except for several short experiments done to confirm part of the results the same two subjects were used throughout. Only two room conditions (approximately 33OC. and ZIOC.) were used and the subjects were exposed to both of these temperatures during the summer and again during the winter. Blood flow measurements were made by the venous occlusion technique. The heat exchange of the foot was obtained by the use of a calorimeter similar to that described by Forster, Ferris and Day (3) for use on the hand. The two were not combined into one instrument as was done by Forster et al. but the calorimetric measurements were made on one foot, while the plethysmograph was used on the other. Such an arrangment has the disadvantage that the two feet were not sub jetted to the same conditions due to the sup-Received for publication February 17, Ig48. l Presented to the Graduate School of Arts and Sciences of the University of Pennsylvania, in partial fulfillment of the requirements for the degree of Doctor of Philosophy.

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“…The basic level of the water in the vertical tube was adjusted to be about the same as that of the water in the bath in which the arm and plethysmograph were immersed; at the higher temperatures used the level sometimes had to be readjusted because the forearm swelled. Abramson et al [1939] show the importance of these points.…”

Section: Methodsmentioning

confidence: 90%

“…The water temperature chosen by various authors has varied from 450 C. [Prinzmetal & Wilson, 1936] to 14°C. [Abramson, Katzenstein & Ferris, 1941], but temperatures ranging from 30 to 370 C. are more usually employed [Lewis & Grant, 1925;Grant, 1938; Abramson, Zazeela & Marrus, 1939]. Using this latter temperature, various workers have found that after the first 30 min.…”

mentioning

confidence: 99%