Anesthetic mortality in swine: a multicenter retrospective analysis

Objective

To investigate the incidence of anesthesia and sedation-related mortality in domestic swine and identify any associated risk factors.

Study design

Multicenter retrospective cohort study.

Animals

A total of 1849 pigs.

Methods

Medical records of pigs undergoing anesthesia or sedation at four veterinary teaching hospitals between August 2018 and July 2023 were reviewed. Variables evaluated included signalment, American Society of Anesthesiologists (ASA) Physical Status Classification, emergency designation, duration of anesthesia or sedation, time of day at anesthesia or sedation initiation, anesthetic agents used, airway management (intubation versus facemask), and 24 hour outcome. Outcome was classified as alive, dead, or euthanized. Each variable was analyzed using univariate logistic regression, with proportions and odds ratios calculated with 95% confidence intervals. Statistical significance was set at p < 0.05.

Results

A total of 1852 records were reviewed, with three records excluded. Of the remaining 1849 cases, 69 (3.7%) were euthanized due to poor prognosis. The overall mortality rate for the remaining pigs was 0.96%, with 17 pigs dead 24 hours postanesthesia. Factors associated with increased odds of mortality [p value; odds ratio (95% confidence interval)] included ASA III–V [p < 0.001; 9.8 (3.6–26.8)], emergency procedure [p < 0.001; 13 (4.0–34.3)], and after-hours procedures [p < 0.001; 5.6 (1.2–25.2)]. No other factors were associated with increased or decreased odds of mortality.

Conclusions and clinical relevance

This is the first study to report the incidence of mortality associated with anesthesia in porcine patients. In the studied population, higher ASA as well as emergency and after-hours procedures were associated with an increase in mortality rate.