Central nervous system oxygen toxicity during routine hyperbaric oxygen therapy

Hyperbaric oxygen therapy is associated with a recognized risk for clinically apparent central nervous system (CNS) toxicity. The risk for oxygen-induced convulsions during routine hyperbaric treatment of most routine conditions is extremely low. However, reports from the 1980's describing the incidence of CNS oxygen toxicity differ significantly from more recent reports since 1996. This retrospective study was conducted to determine the incidence of hyperbaric oxygen-induced seizures among patients treated at our facility for routine, non-emergent indications. In addition, the period studied was selected to examine the incidence of CNS oxygen toxicity between two brands of oxygen delivery hoods. We reviewed our treatment experience for approximately 10,000 routine patient treatments performed prior to and following a change in the brand of oxygen hoods used. Among 20,328 total patient treatments performed from 1992 to 2001, 6 patients experienced an oxygen-toxic seizure for an overall incidence of 1 in 3,388 treatments (0.03%). No difference in seizure incidence was seen between the two brands of oxygen hoods utilized. We conclude that the incidence of oxygen-toxic seizures in our patient population is approximately three-fold greater than historical reports and in agreement with more recent reports. The reason for this apparent increase in incidence of CNS oxygen toxicity is unknown.