Tracer Methods for Estimating Total Water Exchange in Man

Abstract

In analyzing the exchange of body water, 4 general cases present themselves depending on whether heavy water (HDO) or tritium (HTO) is the tracer used and whether or not the volume of body water remains constant throughout the interval under consideration. Mathematical relations are derived in the above 4 cases. Six subjects, placed on measured water intakes, were given HDO and their total body water was assumed to be constant since there were no significant weight changes. Comparison of predicted and measured intakes showed that for flows exceeding 20 1 the 2 & accuracy was about 5%.