This is an observational study that examines the clinical features, the degrees of esophageal injury, physiological markers, and clinical outcomes after paraquat ingestion and seeks to determine what association, if any, may exist between these findings.

The study included 16 of 1410 paraquat subjects who underwent endoscopies at Chang Gung Memorial Hospital between 1980 and 2007.

Corrosive esophageal injuries were classified as grade 1 in 8, 2a in 5, and 2b in 3 patients. No patients had grade 0, 3a, or 3b esophageal injuries. After paraquat ingestion, systemic toxicity occurred, with rapid development of hypoxia, hepatitis, and renal failure in many cases. Hypoxia occurred in 1 (12.5%), 5 (100%), and 3 (100%) patients with grades 1, 2a, and 2b esophageal injury, respectively. There were more hypoxic patients with grades 2a and 2b than those with grade 1 esophageal injury (P < .05). The nadir Pao₂ was lower in patients with grades 2a and 2b than those with grade 1 esophageal injury (P < .05). However, there were no significant differences in terms of acute hepatitis, peak serum alanine aminotransferase, acute renal failure, and peak serum creatinine between the 3 groups (P > .05). Kaplan-Meier analysis did not find any difference in survival between the groups (P > .05).

Paraquat, a mild caustic agent, produces only grades 1, 2a, and 2b esophageal injury. Our findings showed a potential relationship between the degree of hypoxia, mortality, and degree of esophageal injury, although such a low number of study subjects limits the conclusions that can be made by this study.