Possible benefits of Hyperbaric Oxygen Therapy for stroke

Much of the research shows it is best to receive hyperbaric oxygen less than three hours after a stroke. However, there is evidence that increasing oxygen supply to the brain even many years later might help.

Hyperbaric oxygen cannot bring dead brain tissue back to life but it can restore the surrounding, sleeping (dormant) brain cells. In many cases, these dormant areas are responsible for a significant degree of disability, such as paralysis and speech disorders. The treatment can also help to decrease swelling in the brain and prevent more brain cells from dying due to oxygen starvation (hypoxia).⁴

There are numerous reports of improved movement, speech, eyesight and understanding after this treatment. One study followed 50 stroke patients who were no longer improving. Their average age was 62 years, with an average time of 28 months since their stroke. After 60 treatments with hyperbaric oxygen, researchers asked the physical therapists working with these patients to evaluate the participants:

‘The physical therapist's evaluation included range of motion, extremity's strength, bed mobility, bed to chair transfers and body's balance level. By the therapist's evaluations, 100% of the patients showed improvements in one or more functions. Of those, 18% had a mild gain, 48% received a good gain, and 34% an excellent gain.’⁵

In 2009, a team of researchers presented the case of a 65-year-old woman they had treated with hyperbaric oxygen. She suffered from locked-in syndrome, a condition that left her totally paralysed and unable to communicate, although she remained conscious and aware of her surroundings. As there is no known treatment for this condition, the doctors decided to try hyperbaric oxygen. She was placed in a chamber five times a week for a total of 20 treatments. After a month, she had made a significant recovery. There were numerous improvements in her brain stem, movement, speech and general functioning. Researchers noted:

‘With respect to communication, she couldn’t speak in complete sentences, but uttered single words consistently. She showed improvement from no function of the mouth to being primarily fed by mouth….  Nothing was more noticeable than improvements to mobility, as she recovered dramatically from quadriplegia [paralysis in both of her arm and legs] to hemiparesis [weakness on one side] in the left side, which means muscle power was improved from zero in four limbs to 3 in the left side and 4-5 in the right side…. The National Institutes of Health Stroke Scale showed improvement from 32 to 6.⁶

Although there are many differences between locked-in syndrome and stroke, the authors of this report are convinced their findings are significant for stroke survivors. At the same time, they advocate further research on hyperbaric oxygen treatment specifically for stroke:

‘Oxygen delivery may be better in the brain stem region when ischemic infarction occurs. Therefore, we suggest HBO treatment could be used when ischemic stroke happens, especially for brain stem infarction such as LIS [locked-in syndrome].’⁷

Arguments against using Hyperbaric Oxygen Therapy for stroke

There have not been enough high-quality clinical trials to prove or disprove the benefits of hyperbaric oxygen treatment for stroke. In some clinical trials, they found no difference between the group treated with oxygen and the control group, who were treated with ordinary air.⁸ Other studies saw improvements in patients treated with hyperbaric oxygen but it was hard to show that these were due to the treatment rather than to natural healing. Many studies have concluded that we need more clinical trials. The most positive evidence for the benefits of hyperbaric oxygen for stroke often comes from doctors, nurses and other individuals who have observed changes as a result of the treatment. The majority of these observations are not backed up by verifiable evidence. In 2005, a systematic review of the evidence stated:

‘Stroke (four randomised controlled trials, one non-randomised controlled trial and 17 observational studies): Evidence was conflicting. Three fair-quality randomised controlled trials found no benefit in terms of neurological outcomes for patients who received hyperbaric oxygen therapy over those who received pressurised room air or low-pressure oxygen. Two poor-quality controlled trials found improved neurological outcomes on some measures for patients who received Hyperbaric Oxygen therapy. Most observational studies reported improved results for patients who received hyperbaric oxygen therapy.⁹

Another review of hyperbaric oxygen on cerebral ischemia, collated in 2009, showed similar findings. The researchers concluded that while the animal trials are promising, only one of the small number of human trials has shown some benefit.¹⁰

There are some general risks when using hyperbaric oxygen treatment. It is possible for air to become trapped inside the body, which can squeeze the surrounding tissue in the ear or lungs. Other possible side effects include oxygen toxicity, which can cause blurred vision for up to six weeks. In very rare cases, it can inflame the optic nerve, causing blindness.¹¹

There are some pre-existing conditions that make this treatment dangerous. If you suffer from pneumothorax, you should avoid hyperbaric oxygen treatment. You should also avoid it if you are taking certain drugs, including Doxorubicin (Adriamycin), which is used in chemotherapy, and Disulfiram  (Antabuse), which is prescribed for alcoholism. Finally, you might be advised not to use hyperbaric oxygen therapy while you have a chest infection, a high temperature, or if you have had recent chest surgery.¹²

Case histories

1. This news report shows HBOT being used in stroke therapy:

Notes and references

1. 'The Undersea and Hyperbaric Medical Society (UHMS)' by Hyperbaric Oxygen Therapy Committee. In Guidelines: Indications for Hyperbaric Oxygen. Kensington, MD: UHMS; 2000.
2. 'Hyperbaric oxygen in neurosurgery' by B.R. Fischer, E.J. Speckmann, C. Greiner, A. Gorji, J. Wölfer and H. Wassmann. In Acta Neurochirurgica Volume 151, Number 4 / April, 2009.
3. Bennet MH, Wasiak J, Schnabel A, Kranke P, French C “Hyperbaric Oxygen Therapy for Acute Ischemic Stroke”, Stroke, 2010, vol. 41, e185-6 [NOTE: In this paper, they state that HBOT treatment is typically administered for 60-120 minutes, not 30-120 minutes, as stated in this entry.]
4. Kewal K. Jain, Textbook of Hyperbaric Medicine. Hogrefe Publishing GmbH, 2009
5. 'Hyperbaric Oxygen for Treatment of Stroke & Traumatic Brain Injuries' by David A. Steenblock. Presented at the National Stroke Association Conference in Boston, October 16-18 1997.
6. 'Experience of Hyperbaric Oxygen Treatment on a Patient with Acute Ischemic Locked-in Syndrome' by Shang-Lin Chiang, Shin-Tsu Chang, Shao-Yuan Chen, Chia-Huei Lin, Kao-Chung Tsai1,Cheng-Chiang Chang, and Liang-Cheng Chen. In Journal of Medical Science 2009;29(4):199-204
7. 'Experience of Hyperbaric Oxygen Treatment on a Patient with Acute Ischemic Locked-in Syndrome' by Shang-Lin Chiang, Shin-Tsu Chang, Shao-Yuan Chen, Chia-Huei Lin, Kao-Chung Tsai1,Cheng-Chiang Chang, and Liang-Cheng Chen. In Journal of Medical Science 2009;29(4):199-204
8. 'Hyperbaric Oxygen in Acute Ischemic Stroke Trial Pilot Study, 1999-2003'. In Stroke 2003;34:571-574. Also 'Hyperbaric oxygen therapy for acute ischemic stroke' by Bennett MH, Wasiak J, Schnabel A, Kranke P, French C. In Cochrane Review: The Cochrane Library, Issue 1, 2006. Oxford.
9. 'Hyperbaric oxygen therapy for stroke: a systematic review of the evidence' by Carson, S, McDonagh M, Russman B, Helfand M. In Clinical Rehabilitation 2005; 19: 819-833.
10. 'Hyperbaric oxygen therapy and cerebral ischemia: neuroprotective mechanisms' by Matchett, Gerald A., Martin, Robert D., Zhang, John H. In Neurological Research, Volume 31, Number 2, March 2009, pp 114-121(8).

    'Hyperbaric oxygen therapy has been shown to ameliorate brain injury in a variety of animal models including focal cerebral ischemia, global cerebral ischemia, neonatal hypoxia-ischemia and subarachnoid hemorrhage. Small human trials of hyperbaric oxygen therapy in focal ischemia have not shown benefit, although one trial of hyperbaric oxygen therapy before cardiopulmonary bypass demonstrated improved neuropsychological and inflammatory outcomes with hyperbaric oxygen therapy. Hyperbaric oxygen therapy is associated with improved cerebral oxygenation, reduced blood-brain barrier breakdown, decreased inflammation, reduced cerebral edema, decreased intracranial pressure, reduced oxidative burden, reduced metabolic derangement, decreased apoptotic cell death and increased neural regeneration.'

11. William, P., PhD. Fife; Jolie, PhD. Bookspan (2004). Textbook of hyperbaric medicine. Seattle: Hogrefe & Huber Publishers.
12. 'Effect of Hyperbaric Oxygenation on Spasticity in Stroke Patients' by Jain KK 1989. In Journal of Hyperbaric Medicine 4 (2): 55–61