Blood gases, acid base equilibrium and cholinesterase activity in dogs intoxicated with organophosphate insecticide EPN before and after treatment

ABSTRACT

The study was carried out on twenty-five mongrel dogs. These were divided into three groups control group [10 dogs], intoxicated group [5 dogs], and treated group after intoxication [10 dogs]. Dogs were intoxicated with organophosphate insecticide [EPN] to investigate the changes that might be encountered in acid-base equilibrium, blood gases and cholinesterase activity, before and after treatment. It was found that dogs intoxicated with EPN developed metabolic acidosis manifested by significant lowering of the pH of the blood [academia] and bicarbonate level. Moreover a decrease in the PaCO[2] and to a lesser extent in the PaO[2] was encountered. A more significant diminution in plasma cholinestrase activity than red cell cholinesterase activity occurs. Treatment of the intoxicated dogs by sodium bicarbonate revealed a significant improvement in the pH of the blood and bicarbonate levels, while treatment by atropine and toxogonin slightly improved them. Again PaO[2] and PaCO[2] were corrected nearly to their original values after atropine and toxogonin and to a lesser extent after sodium bicarbonate therapy A significant improvement in the activity of plasma cholinesterase level and to a lesser extent the red cell cholinesterase following treatment with atropine and Toxogonin occured, while sodium bicarbonate slightly improved both. It is recommended that routine blood gases and acid base equilibrium tests should be carried out in cases of moderate or severe organo-phosphate insecticide poisoning in order to discover early metabolic acidosis. Early initiation of bicarbonate therapy, together with the ordinary therapeutic regimen [atropine and Toxogonin], or bicarbonate with atropine only whenever Toxogonin is not available, is helpful