Total and partial gas tensions of human bladder urine

Abstract

The total and partial gas tensions of human bladder urine were studied by a modified Krogh micromanometric method combined with fractional absorption analysis and the use of a Clark oxygen electrode. Consumption of O2 by reducing substances in urine was determined and correlated with its specific gravity and pH. Oxygen tension of bladder urine averages 50 mm Hg during air breathing and 58 mm Hg during pure O2 breathing. Pco2 ranges from 47 to 152 mm Hg and correlates best with urinary pH. The average figure for urine nitrogen tension, 550 mm Hg, agrees closely with the calculated Pn2 of alveolar air. Total gas tension of urine is typically about 60 mm Hg less than atmospheric and changes in total gas tension are shown to reflect changes in Pco2, the tensions of the other gases remaining relatively constant in an experimental period. The physiological significance of these total and partial gas tensions is discussed. A counter-current gas diffusion system is proposed to account for the difference between the oxygen tension of urine and renal venous blood. Submitted on September 24, 1959