The Effects of Neutralization Therapy for Acute Alkali Ingestion in Rabbits

ABSTRACT

PURPOSE: To evaluate temperature changes in the gastric lumen and the efficacy of weak acid neutralization against the ingestion of a strong alkaline commercial agent. METHODS: A total of 23 male New Zealand White rabbits were anesthetized with an intramuscular injection of ketamine and xylazine. After gastric lavage, anoro-gastric catheter and an electric thermometer probe were inserted into the stomach. Then 3 mL/kg of room-temperature (24~26degrees C) 1M sodium hydroxide (NaOH) disinfectant was instilled into the gastric lumen. The rabbits were divided into three groups: Group 1 (n=8) was treated with NaOH only and Group 2 (n=7) and Group 3 (n=8) were treated with 39 mL/kg of room-temperature orange juice or water after 5 minutes, respectively. Intra-gastric temperature was continuously measured and compared with arterial pH before alkali insult and 30 minutes later. Gastric pH was measured, and pathological examination of the esophagus, stomach, and duodenum performed after animal sacrifice. RESULTS: Gastric lumen temperatures gradually increased from 32.6degrees C to 38.7degrees C after alkali instillation. Significant decreases in lumen temperature, 7.5degrees C or 12.0degrees C, were observed following treatment with water or orange juice, respectively (p<0.01). Post-treatment temperature did not exceed pre-treatment temperature for the entire observation period. The gastric pH of the neutralization group was much lower than the alkali alone group or the dilution group (7.0+/-0.7 vs. 11.6+/-0.2, or 10.6+/-0.4, respectively, mean+/-SD, p<0.01). In gastric microscopic findings, only mucosal injuries were observed in the neutralization groups, while there were no significant differences among groups in terms of esophageal or duodenal injury. CONCLUSION: Neutralization therapy with room-temperature orange juice for acute gastrointestinal injuries caused by liquid alkali did not cause additional thermal injury and might have protective effects against local tissue destruction in the stomach.