Seizure incidence by treatment pressure in patients undergoing hyperbaric oxygen therapy.
Level 4 - case-series / case-control
Retrospective chart review assessing adverse event rates across treatment pressures
What was done
Retrospective chart review of 931 patients undergoing 23,328 hyperbaric oxygen therapy sessions at a university hospital and an outpatient center. The study evaluated the overall incidence of oxygen toxicity seizures and compared seizure risk across maximum treatment pressures of 2.0, 2.4/2.5, and 2.8 atmospheres absolute.
What was found
The overall incidence of oxygen toxicity seizure was 1 in 2,121 treatments (5 per 10,000). Seizure incidence varied significantly by treatment pressure (chi-square(2, 23,540) = 31.38, p < .001): 0 per 10,000 at 2.0 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).
Why it matters
This study quantifies the risk gradient of oxygen toxicity seizures, demonstrating that higher treatment pressures carry a significantly higher seizure risk and should require clear clinical justification.
Limits
Retrospective chart review design subject to documentation limitations. Absolute event counts in the higher-pressure cohorts were extremely small (single cases), resulting in substantial statistical imprecision. The abstract does not report patient indications, underlying comorbidities, session duration, or concurrent medications.
Cited by
- supports Hyperbaric oxygen therapy guidelines cap exposure at three atmospheres because of the risk of tonic-clonic central nervous system oxygen toxicity seizures above that level.