Effect of tracer infusion site on measurement of bicarbonate-carbon dioxide metabolism in dogs.
Ten dogs were given a primed infusion of H13CO3- for 220 min while under general anesthesia. Isotopic steady state was reached within 60 min in exhaled CO2, femoral arterial blood HCO3-, and femoral venous blood HCO3-. Halfway through each infusion study, the site of tracer infusion was changed either from the central aorta to a peripheral vein, or vice versa. The mean HCO3(-)-CO2 flux measured from blood HCO3- enrichments was 15.7 +/- 2.1 (SD) mmol X kg-1 X h-1. The mean fraction of tracer recovered in exhaled CO2 was 79 +/- 7% (SD) of the infused dose. No significant difference in either HCO3- flux or recovery of tracer was found between the venous and arterial infusions of tracer. These results indicate that when venous administration of HCO3- tracer is compared with central arterial infusion, the initial loss of tracer into expired CO2 is an unimportant consideration in experiments measuring HCO3- kinetics.
D000818:Animals; D001158:Arteries; D001639:Bicarbonates / Q000008:administration & dosage / Q000097:blood / Q000378:metabolism*; D002245:Carbon Dioxide / Q000097:blood / Q000378:metabolism*; D004285:Dogs; D005260:Female; D007263:Infusions, Parenteral; D007700:Kinetics; D014680:Veins
D001639:Bicarbonates; D002245:Carbon Dioxide