Seizure incidence by treatment pressure in patients undergoing hyperbaric oxygen therapy

Introduction: Hyperbaric oxygen (HBO₂) therapy uses different maximum treatment pressures. A side effect of HBO₂ is oxygen toxicity seizure. The purpose of this study was to determine the overall incidence of oxygen toxicity seizure and assess risk at different treatment pressures. Method: A retrospective chart review was performed on patients who underwent HBO₂ at a university hospital and at an outpatient center. Statistical analysis was performed to determine overall incidence of seizure and identify risk factors including maximum treatment pressure. Results: A total of 931 patients were identified representing a total of 23,328 treatments. The overall incidence of seizure was one in 2,121 treatments (five per 10,000). There were zero per 10,000 at 2.0 atmospheres absolute / atm abs (0/16,430), 15 per 10,000 at 2.4/2.5 atm abs (1/669) and 51 per 10,000 at 2.8 atm abs (1/197). There was a statistically significant difference for seizure between the different pressures (? ² (2, 23,540) = 31.38, p < .001). Discussion: The overall incidence of oxygen toxicity seizure in this study is consistent with recent reports. This study demonstrated a statistically significant increased risk of seizure with increasing treatment pressure. Treatment at higher pressure should be chosen based on demonstrable benefit with a clear understanding of increased risk with higher pressure.