The Estimation of Pesticide Retrieved by Gastric Lavage in Acute Organophosphorus Poisoning

Objective: There is insufficient evidence on the effectiveness of gastric lavage in organophosphorus poisoning. This study was done to quantitate the level of chlorpyrifos and quinalphos retrieved in gastric lavage fluid.Methods: Patients presenting within six hours of ingesting quinalphos or chlorpyrifos with International Program on Chemical Safety Poison Severity Score (IPCS PSS) grade 2 or more were included in the study. After the stabilisation of patients, gastric lavage was performed with alliquotes of 200 ml of normal saline till aspirate became clear. Quantification of the pesticide was done in the first 10 ml of lavage fluid aspirated out and in blood with gas chromatography with triple quadruple mass spectrometer (GC-MSMS).Results: There were six patients in each pesticide group. Mean time for reaching hospital after the ingestion of pesticide was 2.8 ± 1.1(range 1.25-6) hours. Median quantity of chlorpyrifos in the lavage fluid was 10.24 (IQR 14.36) µg/L and in quinalphos, it was 1360.62 (IQR 1691.2) µg/L. Other compounds detected in lavage fluid and confirmed in blood were endosulfan, diazinon, pirimiphos, pyridafenthion, pyrazophos, pirimiphos ethyl, and azinphos.Conclusion: Chlorpyrifos and quinalphos are detected in lavage fluid after one hour of ingestion and few milligrams are retrieved by gastric lavage. The presence of other pesticides including endosulfan were confirmed in lavage fluid.