Seizure incidence by treatment pressure in patients undergoing hyperbaric oxygen therapy.

Background: 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.

Methods: 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 (χ2 (2, 23,540) = 31.38, p < .001).

Conclusions: 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.