Quantifying the effect of intravascular perfluorocarbon on xenon elimination from canine muscle

Intravenous infusions of perfluorocarbon (PFC) may improve decompression sickness outcome in animals by accelerating inert gas elimination from tissue, but any such effect has not been quantified experimentally. In this study we used an animal model of tissue Xe kinetics to test this hypothesis and to quantify the effect of PFC. Eight dogs were ventilated with dilute 133Xe in air for 4 h of Xe uptake. Four dogs were then given an infusion (20 ml/kg iv) of a 40% (vol/vol) perfluorodecalin-glycerol emulsion, and four control dogs were given only isotonic glycerol. All were then switched to open-circuit air breathing for 4 h of Xe elimination. During this time Xe radioactivity-time curves were recorded from two intact hind leg muscles, and the Xe mean residence times during elimination were estimated using an analysis by moments and compared by group. Tissue blood flows were measured using microspheres once during Xe uptake and twice during Xe elimination, and cardiac outputs were measured by thermodilution at 30-min intervals. In the PFC group the measured circulating PFC fraction increased the calculated Xe solubility by an average factor of 1.77 and so was expected to increase the Xe elimination rate by 77%. The observed Xe mean residence times on elimination for the PFC group averaged 33.5 min [95% confidence interval (CI) 19.5-47.6] compared with the glycerol control average of 70.1 min (95% CI 56.1-84.2), representing an increase in the rate of Xe elimination by a factor of 2.09 or 109%.(ABSTRACT TRUNCATED AT 250 WORDS)