Renal dead space as a function of urine flow in the anesthetized dog.

F ROM studies in dogs of the relationship between urine flow and appearance time in the bladder urine of various substances injected into the blood stream, Morales and his collaborators (I) suggested that “renal dead space increases almost in proportion to urine flow.” The calculations of Bojesen (2) suggest that proportionality also exists between the volume of the renal pelvis and urine flow. There are presented here data and calculations on the relationships between renal dead space (from the glomeruli to the bladder), the rate of urine flow, and the mean transit time of glomerular substances from the renal artery to the bladder. The data have been obtained by the application of an experimental technique outlined in the previous communication (3). In effect, the indicator-dilution method introduced by Stewart (4) and developed by Hamilton and his collaborators (5) has been applied to the urinary system.