Occurrence and clinical relevance of postoperative hypernatremia in dogs undergoing cholecystectomy

BACKGROUND: Patients undergoing cholecystectomy have not been reported previously to develop clinically relevant postoperative hypernatremia. OBJECTIVES: Describe the frequency of postoperative hypernatremia in dogs undergoing cholecystectomy and its clinical relevance (duration of hospitalization and survival). ANIMALS: Thirty‐seven dogs undergoing cholecystectomy at 2 private referral hospitals. METHODS: Retrospective study of dogs undergoing cholecystectomy with available preoperative and postoperative serum sodium concentrations. RESULTS: Postoperative hypernatremia (>150 mEq/L) was common (56%; 95% confidence interval [CI], 40%‐70%) and was associated with significantly higher mortality compared to nonhypernatremic patients (52%; 95% CI, 30%‐70% vs 12.5%; 95% CI, 2%‐40%; P = .02). Nonsurvivors had higher mean postoperative peak serum sodium concentrations (155 mEq/L; range, 146‐172) than survivors (150 mEq/L; range, 142‐156; P = .01). Dogs developing hypernatremia within 6 hours after surgery had 7.7 higher odds of nonsurvival (odds ratio [OR], 7.7; 95% CI, 5.9‐9.4). A delta value (serum sodium concentration on admission [T0] − serum sodium concentration 6 hours postoperatively [T2]) of ≥10 mEq/L carried 3.3 higher odds of mortality (OR, 3.3; 95% CI, 1.6‐5.1). All dogs with a postoperative peak sodium concentration >160 mEq/L did not survive. Admission acute patient physiologic laboratory evaluation fast (APPLE(fast)) scores were not different between survivors and nonsurvivors or between postoperative hypernatremic and normonatremic patients. Hospitalization time was no different between hypernatremic and normonatremic patients (6 days vs 4.5 days; P = .15). Dogs with gallbladder mucocele were more likely to develop postoperative hypernatremia and have poorer outcomes. CONCLUSIONS: Hypernatremia was a common and clinically relevant postoperative complication in dogs after cholecystectomy. Detection of hypernatremia within 6 hours after surgery may be associated with poorer outcomes.