Strongly acidic gastroesophageal reflux and esophageal lumen pH before and after esophageal lavage with water or two bicarbonate concentrations in anesthetized dogs

Abstract

OBJECTIVE To increase acidic esophageal lumen pH in dogs that developed gastroesophageal reflux (GER) during anesthesia. We compared water and 2 different bicarbonate concentrations. ANIMALS 112 healthy, nonbrachycephalic dogs presented for ovariectomy. PROCEDURES Following standard anesthesia and surgery protocols for ovariectomy in all dogs, esophageal lumen impedance and pH were monitored using a dedicated probe. Esophageal impedance indicates the presence of GER whereas pH indicates the acidity level. Dogs with strongly acidic GER and an esophageal lumen pH value < 4.0 were included in the study, and lavage was performed with either tap water, bicarbonate 1%, or bicarbonate 2% until the pH increased to > 4.0. The effect of lavage on esophageal pH was compared using the Kruskal–Wallis and Wilcoxon 2 sample tests. Associations between lavage and pH changes were determined. RESULTS Of 48/112 dogs with strongly acidic GER, 33% neutralized their esophageal pH during surgery. For the 32 dogs that maintained an esophageal lumen pH value < 4, esophageal lavage with water increased the lumen pH to > 4 in 78.6% of dogs, whereas both bicarbonate concentrations increased it in 100% of the dogs to a more neutral pH (P < .0001). The dogs in the water group were more likely to regurgitate after anesthesia (36% vs 0% in both bicarbonate groups, P = .028). CLINICAL RELEVANCE Bicarbonate 1% and 2% increased esophageal lumen pH to more than 4 after strongly acidic GER. Lavage with water was mildly effective, but required large volumes and predisposed to further regurgitation after anesthesia.