SIMULTANEOUS DETERMINATIONS OF BLOOD VOLUME BY CO AND DYE (T-1824) UNDER VARIOUS CONDITIONS

Abstract

An improved method for the detn. of blood vol. with CO is described. Simultaneous detns. of the blood vol. with CO and with dye (T-1824) were made on 5 normal dogs, 9 splenec-tomized dogs, 4 dogs in which the blood vol. was reduced by hemorrhage, 6 dogs in which the blood vol. was decreased by muscle trauma, 8 normal resting men and 3 men working under tropical conditions. In all of the 14 measurements on resting and working man and in 23 of the 29 animal expts., the CO blood vols. agree with the dye blood vols. to within [plus or minus]10%. In all 14 of the human expts. and in 26 of the 29 animal expts. the ratios of the body hematocrit (red cell vol. detd. by CO/the red cell vol. detd. by CO + plasma vol. detd. by dye) to the observed central venous or arterial hema-tocrit fall between 0.90 and 1.08. The possible error in the CO method caused by myoglobin is discussed. The results indicate that the amt. of blood present in the small vessels is not great enough for the unequal distribution of red cells present in these vessels to affect greatly the estimation of the blood vol. as calculated from the dye and hematocrit reading under the conditions studied.