Gastric Lavage for Acute Organophosphate Poisoning, June 20, 1986

Gastric Lavage for Acute Organophosphate Poisoning, June 20, 1986

Organophosphates are active ingredients in many pesticides, and the number of poisoning cases is increasing along with the widespread use of pesticides. Clinical manifestations of organophosphate poisoning include abdominal pain, nausea, vomiting, shock, coma, and in severe cases, pupil constriction, muscle tremors, excessive sweating, and a distinctive garlic-like odor. Additionally, reduced serum cholinesterase activity is an important diagnostic indicator of organophosphate pesticide poisoning; however, since this indicator often decreases in liver disease, myocardial infarction, hypertension, and gastrointestinal tumors, a drop in serum cholinesterase activity is not specific. The most important emergency measures for treating this condition are gastric lavage, emesis induction, and emetic stimulation. Some argue that emesis induction and emetic stimulation may be better than gastric lavage, but most scholars believe that gastric lavage is still more thorough. Regardless of how long ago organophosphate pesticides were ingested, gastric lavage must be performed; even after gastric lavage, if there is suspicion that the lavage was incomplete, another round of lavage can be carried out. There are two methods of gastric lavage: tube lavage and open-lavage. The washing solution typically uses a 2% NaHCO₃ solution (for dichlorvos, use 1:5000 ppm), saline, or plain water. Generally, it is recommended to use plain water for gastric lavage when the type of pesticide is unknown, because absorption of 2% NaHCO₃ can easily lead to alkalosis. Open-lavage is performed when poisoning is severe and tube lavage fails within four hours. Since open-lavage inevitably causes additional trauma to the patient, it should only be carried out as a last resort.

Severe organophosphate pesticide poisoning can often cause acute pulmonary edema, cerebral edema, and respiratory failure; therefore, treatment should include: ① oxygen therapy; ② respiratory stimulants; ③ scopolamine, which is highly effective in rescuing respiratory failure; ④ cardiac stimulants to improve cardiopulmonary function; ⑤ correction of electrolyte disturbances.