[abstract] Oxygen toxicity seizure during hyperbaric oxygen therapy –Incidence and potential risk factors

Abstract

Introduction: Oxygen toxicity seizures are a known side effect of hyperbaric oxygen therapy (HBO2T). Studies reporting the incidence of seizure vary significantly, from as low as 1 in 10,000 to as high as one in 1,800 treatments. Questions remain regarding the role of treatment protocols and patient risk factors associated with these seizures. Methods: A retrospective analysis was completed of 323 patients undergoing a total of 4589 HBO2Ts at a major university hospital from January 2005-December 2010. Patients underwent treatment for a variety of indications, both elective and emergent. Overall incidence was determined, along with examining multiple factors including treatment parameters and patient factors. Results: The overall incidence of seizure during HBO2T was 1 in 918 HBO2T (0.11%). The incidence comparing those receiving an air break verses no air break was three in 560 (0.54%) versus two in 4029 (0.05%) respectively, which was statistically significant (p=0.015). Interestingly, all three seizures in the airbreak group came soon after the air break. Comparing incidence rates at different maximum pressures did not demonstrate a statistically significant difference in risk with increased pressure. The incidence of a history of alcohol abuse was 20% in the seizure group (n=5) versus 8% in the controls (n=318) with p=0.35, while the incidence of diabetes was 40% in the seizure group (n=5) versus 14% in the controls (n=318) with p=0.16. Conclusion: Our findings suggest a higher incidence of seizure during HBO2T than has been previously reported. Air break versus no air break was found to be a statistically significant risk factor, with three seizures occurring soon after the air break was administered. These findings suggest that the true incidence of oxygen toxicity seizure may be higher than previously reported. Furthermore, the findings suggest air breaks as a potential trigger for seizure.