Changes in absorbance at 413 nm in plasma from three rodent species exposed to phosgene

Mice, rats and guinea pigs were exposed to phosgene (COCl2), a highly irritating and oxidizing gas. Animals were exposed to 87 mg/m3 phosgene for 20 min in a whole-body exposure chamber. Within 55-65 minutes after the start of exposure, plasma was scanned spectrophotometrically from 200-600 nm. A distinct and significant increase in area under the curve in the Soret band region at 413 nm was observed in plasma from phosgene-exposed animals when compared with air-exposed controls in all three species. These peaks were consistent with hemoglobin, an indication that the integrity of the erythrocyte membrane had been compromised by exposure. An erythrocyte osmotic fragility assay on blood from mice exposed to phosgene indicated that 30% less NaCl was needed to cause 50% hemolysis compared to air-exposed mice. These results suggest a new mechanism of phosgene-induced acute lung injury that may be linked, in part, to a direct attack on the erythrocyte membrane.