DETERMINATION OF THE VOLUME OF THE EXTRACELLULAR FLUID OF THE BODY WITH RADIOACTIVE SODIUM.

摘要: A method for measuring the volume of fluid available distribution sodium (sodium space) by use its radioactive isotope (Na(24)) has been described and accuracy discussed. Simultaneous determinations plasma means blue dye T-1824 extracellular employing radiosodium thiocyanate have made in normal subjects. Repeated measurements were at varying periods time same individuals. In order to establish rate diffusion equilibrium between serum serous effusions, simultaneous samples both obtained intervals after intravenous injection these substances. Since evidence literature indicates that there is an excess mainly limited bone, which cannot be attributed phase, experiments on dogs man so devised ratio tissue concentration chemically determined chloride could calculated. The following conclusions may drawn from results this investigation: 1. Radiosodium administration spreads rapidly during first 3 hours into a represents approximately 25 per cent body weight man. Thereafter 6 it diffuses more slowly certain spaces-the central nervous system probably skeleton. interstitial represent 15 85 space respectively. 2. Diffusion not established transudates edematous patients until 9 12 3. Until complete information available, concluded unless difference repeated observations individual exceeds +/-1.38 liters no significant change providing activity standard are range 40 counts minute milliliter with counting apparatus used. As increases, error becomes less because correlation magnitude activity. 4. Climatic conditions produce changes blood or fluid. 5. dog, radiosodium, bone reaches maximum (3 hours). extra skeleton dog equal about (1/4) total body, assuming volume. Similar amounts found Na(24). 6. Correction reduced average value 3.7 18.9 cent. corrected subjects 15.9 21.1 compared 17.7 liters, representing 23.5 weight. 7. most useful calculating data as follows: See PDF Equation This amount phase. 8. While neither nor gives precise estimates fluid, both. For clinical use, superior ready availability substance, required.