abs: Reverse Trendelenburg and Reflux Anesthetized Dogs

The incidence of gastroesophageal reflux (GER) in anesthetized dogs warrants investigation into perioperative preventative strategies. This study aimed to determine if a reverse Trendelenburg position (RT) would decrease the incidence of GER compared to a horizontal position (HP) in anesthetized dogs.

Methods: Twenty-four client-owned dogs admitted for elective stifle surgeries were anesthetized with a standard anesthetic protocol and randomly assigned to be positioned either in a 15-degree RT or in a HP for the procedure. Dogs with a history of gastrointestinal signs or administered gastroprotectant therapy within one month of surgery were excluded. Continuous pH monitoring was documented throughout the procedure by a 6.4-French (2.13 mm) esophageal pH probe positioned in the distal esophagus via the oral cavity. Esophageal reflux was defined as a pH less than 4.0 (gastric) or greater than 7.5 (biliary) for more than thirty seconds. The proportions of dogs developing reflux were compared between groups using Fisher’s exact test. Time to reflux development was compared using survival curves and the Gehan-Breslow-Wilcoxon test. Statistical significance was set as p < 0.05.