Lisa,
Thanks for your question. Let me start with a few standard operational recommendations. As always begin with a detailed History and Physical by your hyperbaric provider. Discussion with the patient’s neurologist should provide greater insight regarding the seizure history and current seizure medication regimen. As well, labs to confirm that the medication is within therapeutic range. The following was posted December 7, 2020, on the UHMS MEDFAQ website. I have included the question and response from the UHMS Safety Committee.

Q: For patients with a history of seizure(s), is there literature to define their risk for an O2-induced seizure? Is there any sort of consensus on how to alter a treatment protocol such as increased number of air breaks or treatment depth? Are there thresholds to clear to treat such as length of time to be seizure-free (on or off antiseizure meds)? Or is such a patient at the same risk as any other patient? I realize that each seizure patient may be different (focal vs. generalized and not a question of remote h/o febrile seizure in childhood).

Q: For patients with a history of seizure(s), is there literature to define their risk for an O2-induced seizure?

• Hyperbaric Oxygen Therapy: Side Effects Defined and Quantified; Marvin Heyboer III,* Deepali Sharma,William Santiago, and Norman McCulloch; ADVANCES IN WOUND CARE, VOLUME 6, NUMBER 6

• Seizure incidence by treatment pressure in patients undergoing hyperbaric oxygen treatment; Marvin Heyboer III, Shane Jennings, William D. Grant, Cindy Ojevwe, Joseph Byrne, Susan M. Wojcik; UHM 2014, Vol. 41, No. 5

• Oxygen toxicity seizures: 20 years' experience from a single hyperbaric unit; Neil D G Branham; Diving and Hyperbaric Medicine, Vol 41, No. 4, December 2011

Q: Is there any sort of consensus on how to alter a treatment protocol such as increased number of air breaks or treatment depth?

A: No. Practically speaking one may decreased depth, decrease length, and add air breaks. No study has demonstrated efficacy, but it makes theoretical sense.
Are there thresholds to clear to treat such as length of time to be seizure-free (on or off antiseizure meds)?

A: No. Recommendation is stable on anti-seizure medication. Epilepsy has never been identified as an actual risk factor although theoretical risk.
Or is such a patient at the same risk as any other patient?

A: Literature says same risk, but not unreasonable during informed consent to acknowledge possible increased risk.

There is no formula for adjusting a dive profile to decrease the likelihood of having a seizure. Likewise, there is no model, formula or nomogram that forecasts the likelihood of an oxygen induced seizure when patient presents with a history of seizure disorder. The important thing is to make sure that the patient’s seizure medications are appropriately dosed and taken by the patient. Blood levels if available should be obtained. We assume that O2 induced seizures are more likely when patients with an underlying seizure disorder (or fever) is present but even that assumption is mostly an educated guess.

In terms of adjusting the profile, of course it depends on the pressure you are using for treatment and what the disorder being treated is. If it is a 2.4 ATA profile I would begin increasing the frequency of air breaks to every 20 minutes for a 5 minute duration. If a seizure occurs there, I would reduce the pressure to 2.0 ATA and continue air breaks (probably every 30 minutes). I would avoid any futher reduction of pressure if possible.

If it is a 2.0 ATA profile I would introduce air breaks if none are being used. I would begin with 5 minutes every 30 minutes. If a seizure occurs I would introduce the air breaks every 20 minutes for 5 minutes. I would not reduce pressure downward from 2.0 ATA.

If it is a 2.8 or 3.0 ATA profile, I would increase the frequency of air breaks, but a stepwise pressure decrease might be needed as well. Obviously, these treatments would be for a diving case or perhaps a gas gangrene or necrotizing fasciitis. In that case pressures should be maintained if at all possible and the best option is to increase the frequency of air breaks. Care should be taken in ascending to a lower pressure especially in a table VI or other similar profile for DCS so as to not make the DCS or Air Embolism worse.

I hope this provides you with some guidance. In my experience, it is an empirical adjustment. Obviously, you will have selected a particular treatment profile because you thought it was appropriate for that patient. I would avoid radical changes and make only minor adjustments. In my experience, the shortening of O2 periods and increased frequencies of air breaks usually works well.

REFERENCES:
1. https://uhms.org/resources/medfaqs-frequently-asked-questions-faq/search/1-%20Search.html?yrfaqsearch=seizure

I hope this helps. Thanks for the question!

Thanks for the great information!! Will pass this to our physicians...

Jeff has given you great information! In the end, this is a physician choice. In my experience, and not being cavalier, we never had an OxTox seizure in a patient with seizure history. Did I change profiles to compensate for that? No.

What I was most interested in finding out was the frequency of seizures on the current medical regimen. If seizures were well controlled, there is no reason why a hyperbaric treatment should put the patient at an exceedingly higher risk than the general population.

I also wanted to know when the last seizure occurred and if there was a 'trigger' for the seizure.

I can tell you that an inside observer with seizure history in a multiplace chamber ... that's definitely a no-go.

Good luck.

Hello Dr. Worth,

Thank you for your insight. We will be checking his Depakote levels, Magnesium, and CMP today and reccomended that he takes 15mg of Vitamin E daily while doing HBOT. There were no known triggers during his last seizure. He did tell me that he was laying down during all of his seizures. Im waiting for his results and also his neurologists last notes.

Thanks again for your help
Lisa