Venous Congestion of the Extremities in Relation to Blood Volume Determinations and to Mixing Curves of Carbon Monoxide and T-1824 in Normal Human Subjects 1

The Effect of Experimental Venous Obstruction on Salt and Water Distribution and Excretion in Man

“…The increases in plasma protein concentration and hematocrit observed in the early stage of the tourniquet period are in accord with previous observations that tourniquets applied on the extremities at subdiastolic pressure produce a rapid reduction in plasma volume (1,3). Whether any decrease in circulating volume, regardless of etiology, will initiate a movement of salt and water into the fluid phase of the extracellular compartment remains to be determined.…”

“…This pooling occurs quickly and when produced experimentally by tourniquets applied to three extremities, has been shown to trap a volume equivalent to about 15 to 20 per cent of the total circulating volume within 10 minutes (2,3). Elevation of venous pressure, according to Starling's fundamental hypothesis, will, in addition, initiate a filtration of fluid out of the capillaries into the local tissues (1,2).…”

Simultaneous Determinations of the Total Volume of Red Blood Cells by Use of Carbon Monoxide and Chromium51 IN HEALTHY AND DISEASED HUMAN SUBJECTS1

“…The characteristics of the time: concentration curve of CO in the blood are not consistent with continuing loss of CO by metabolism or excretion after the first 20 minutes of rebreathing (15). Care was taken to prevent loss of gas through leaks in the apparatus during each experiment.…”

“…The method used for estimating CO-available volume has been described fully (14,15). Carbon monoxide was delivered into a small, closed system into which the subject rebreathed for 20 minutes, 02 being added as required.…”

“…Erythrocytes may also be labeled with carbon monoxide gas, and this is the basis of methods which have been employed widely to estimate blood volume and total circulating hemoglobin (11)(12)(13)(14)(15)(16)(17). It has long been suspected that the volume of distribution of carbon monoxide in the body (henceforth to be called "CO-available volume") may be larger than true blood volume, since the gas has affinity for pigments which are located extravascularly, such as myoglobin or non-circulating hemoglobin (11,18,19).…”