Objective: To determine whether in-vivo neutralization therapy for acid ingestions will superimpose a thermal injury upon tissue already damaged by acid.
Methods: An in-vivo canine model was used with repeated measures of tissue and luminal temperatures. All dogs were placed under halothane general anesthesia. The stomach was exteriorized and temperature probes were placed in the lumen and mucosa. 25 mL of 0.5 N HCl (25 degrees C) was placed in the gastric lumen followed 5 minutes later by 75 mL of either 8% NaHCO3 neutralization (25 degrees C, n = 10) or water dilution (25 degrees C, n = 10). Temperature measurements were recorded at specified intervals for 5 minutes post HCl acid exposure and for 30 minutes post treatment. Temperature profiles were analyzed by repeated-measures ANOVA. Post-treatment changes were evaluated using signed-rank tests.
Results: In both treatment groups, treatment resulted in significant decreases in initial mucosa and intraluminal temperatures. Both the mucosa and intraluminal temperatures decreased immediately after treatment with HCO3 by an average of 1.6 degrees C (p = 0.05). In the water dilution treatment group, both temperatures decreased by 1.1 degrees C (p = 0.05). Ensuing post-treatment temperatures increased but did not reach baseline temperatures at any time up to 30 minutes post treatment.
Conclusions: In the in-vivo setting, there is no evidence of hazardous temperature elevation when a weak alkali or dilution therapy is used to neutralize strong acid-induced injury. Contraindication of this form of emergency treatment should not be based on the preconceived idea that a resultant exothermic reaction will cause a superimposed thermal injury. Further clinical study is needed to determine the clinical utility of this emergency therapeutic modality.