Effects of time of contact and concentration of caustic agent on generation of injuries.
OBJECTIVE
Solid caustic soda (CS) ingestion levels continue high in Brazil. The aggressiveness of a caustic agent depends, among other factors, on its concentration and time of contact with mucosa. However, the interdependence of these factors in the production of caustic lesion in the esophageal mucosa is not known, especially regarding CS as the strongest corrosive agent. We analyze the effects of concentration and time of contact on the aggressiveness of CS to the esophagus of live animals.


METHODS
One milliliter of CS at concentrations between 1.83% and 73.33% was applied to rats. The solution was kept in contact with the mucosa for 10 to 120 minutes. Internal and external organ aspects were analyzed and the epithelium, submucosa, muscle layer, and adventitia were analyzed microscopically


RESULTS
Epithelial necrosis was observed at all concentrations. Among the necrotic layers, the submucosa was observed starting at the 7.33% concentration, and the muscular layer and adventitia were observed at 14.66% concentration. Damage to the pulmonary parenchyma and trachea occurred at 33.66% after 10 minutes, and perforation of the esophagus was observed only after 120 minutes. After 10 minutes, important corrosive lesions installed in the esophageal layers, expanding in depth and superficial extension. The use of heparin had no effect on the production of lesions.


CONCLUSIONS
Ten minutes were sufficient to provoke necrosis, and longer contact increased the area of necrosis. Solution concentration levels were more important in damage production: 1.83% was sufficient for epithelial necrosis, 7.33% caused submucosal necrosis, and 14.66% muscle and adventitia necrosis; 33.66% solutions caused lung and trachea damage after 10 minutes and esophageal perforation after 120 minutes.
Mattos
Gustavo M
GM
Ribeirão Preto Medical SchoolRibeirão Preto Medical School, University of São Paulo, São Paulo, Brazil.
Lopes
Daniel Dias
DD
Mamede
Rui Celso Martins
RC
Ricz
Hilton
H
Mello-Filho
Francisco V
FV
Neto
José Barbieri
JB
D000818:Animals; D002057:Burns, Chemical / Q000209:etiology* / Q000473:pathology; D002424:Caustics / Q000008:administration & dosage*; D004195:Disease Models, Animal; D004305:Dose-Response Relationship, Drug; D004940:Esophageal Stenosis / Q000139:chemically induced* / Q000473:pathology; D004947:Esophagus / Q000293:injuries* / Q000473:pathology; D005260:Female; D005500:Follow-Up Studies; D008297:Male; D051381:Rats; D012972:Sodium Hydroxide / Q000008:administration & dosage*; D013997:Time Factors; D015599:Trauma Severity Indices
D002424:Caustics; D012972:Sodium Hydroxide