Pulmonary tissue concentrations of ethchlorvynol after intravenous injection

Noncardiogenic pulmonary edema has been reported to follow the intravenous use of ethchlorvynol (Placidyl) in both human clinical and animal experimental situations. In a further attempt to define ethchlorvynol-pulmonary tissue inter-relations, we measured ethchlorvynol concentrations in venous and arterial blood and lung and liver tissue of dogs after intravenous injection of 15 to 25 mg of the drug per kg of body weight. In 10 dogs, the mean +/- SEM lung concentrations 1, 3, and 5 min after injection were 70 +/- 20, 50 +/- 13, and 24 +/- 9 mug per g of tissue, respectively. Simultaneous mean +/- SEM venous contrations were 75 +/- 40, 29+/-5, and 22 +/- 5 mug per ml of blood, respectively. During minutes 1 and 3, the liver concentrations were lower than those found in the lung. In an additional 3 dogs, injection of ethchlorvynol into the portal vein led to higher concentrations (at all sample times) in the liver when compared to the lung. In vitro lung slice studies using ethchlorvynol labeled with iodine-131 revealed no active energy-dependent uptake. Intravenously administered ethchlorvynol rapidly fluxes into and out of lung tissue, apparently following the laws of diffusion.