Common Uses and Adverse Effects of Hyperbaric Oxygen Therapy in a Cohort of Small Animal Patients: A Retrospective Analysis of 2,792 Treatment Sessions

Hyperbaric oxygen therapy (HBOT) is commonly utilized for various human conditionswith a low incidence of major adverse effects (0.002–0.035%). Despite growing use inveterinary patients, there remains a paucity of literature describing its use and associatedcomplications. The purpose of this study was to report clinical use of HBOT in smallanimals and identify the rate of major adverse events at a university teaching hospital.Electronic medical records were searched for small animals receiving HBOT betweenNovember 2012 and February 2020. Data extracted from the medical records includedsignalment, treatment indication, and adverse events. Treatment sessions totaled 2,792in 542 dogs, 24 cats, and 10 pocket pets and exotics. Common indications includedneurologic injuries (50.4%), tissue healing (31.4%), control of oomycete infection (5.5%),neoplasia or post-radiation injury (5.4%), and various miscellaneous conditions (7.4%).Observed minor adverse events included agitation in two dogs and vomiting in threedogs. The most common major adverse event was central nervous system (CNS)oxygen toxicity in 19 dogs. Central nervous system oxygen toxicity, manifesting as focalor generalized seizures, occurred in 0.7% of treatment sessions, with increasing age(p = 0.01) and female sex (p = 0.01) identified as risk factors. One dog developedpulmonary edema following HBOT which is a reported adverse event in humans or mayhave been a manifestation of progression of the dog’s underlying disease. No adverseevents were noted in cats or other species. In conclusion, HBOT appeared safe acrossvarious indications, although oxygen toxicity affecting the CNS was higher than reportsin humans. Future prospective, randomized, controlled trials should evaluate specificclinical indications and outcomes.