Radio-phosphorus in the form H 3 P 32 O 4 , injected in aqueous solution, is found to give flow-dilution curves and values for cardiac output indistinguishable from those obtained with T-1824 in normal anesthetized dogs. The fairly rapid disappearance of the P 32 from systemic blood is a technical advantage if the measurement of output is to be repeated at short intervals.

No abstract

O4 and the dye T-1824 as labels, simultaneous injections were made into the right ventricle and into a peripheral vein, and cardiac output was calculated from the individual flowdilution curves. When a discrepancy beyond the range expected from the use of the two labels occurred, the output from the central injection was always the larger (approximately one-third of the observations, in a small series). This may be attributable to progressive blood loss from sampling, since delayed intraventricular injections under comparable conditions, measure a similarly reduced cardiac output.