Blood Levels of Fluorocarbon Related to Cardiac Sensitization: Part II

Arterial and venous concentrations of three C₂ fluorocarbons • were obtained in unanesthetized beagle dogs during and after 10-minute inhalation exposures. Blood concentration increased rapidly during the first five minutes of exposure and more slowly or not at all thereafter. At termination of exposure, fluorocarbon blood concentration decreased rapidly at first, followed by a more prolonged decline. An arterial-venous difference, observed during and after exposure, suggested a tissue uptake of fluorocarbon. Although a wide range of inspired concentrations—0.5% fluorocarbon 113, 2.5% fluorocarbon 114, and 15.0% fluorocarbon 115—is needed to produce cardiac sensitization, arterial or venous fluorocarbon concentrations associated with these sensitizing levels differ only slightly among the compounds tested: 12.5, 13.8. and 5.8 μg/ml arterial and 4.9. 7.2, and 3.9 μg/ml venous respectively. Sensitizing blood levels from 25 to 35 μg/ml arterial and from 18 to 23 μg/ml venous have been reported for C₁ fluorocarbons 11 and 12.