Harpur
Hyperbaric oxygen administration did not improve functional or disability scores in chronic stable multiple sclerosis.
Clinical Bottom Line: 1. No evidence that hyperbaric oxygen results in improvement in disability score or functional score in chronic multiple sclerosis.
Appraised by: Mike Bennett, Dept of Diving and Hyperbaric Medicine, Prince of Wales Hospital Sydney; Monday, 1 March 1999
Clinical Scenario: A patient with chronic stable multiple sclerosis asked if the administration of hyperbaric oxygen would improve her condition. Three-part Question: In patients with chronic stable multiple sclerosis, does the administration of hyperbaric oxygen compared to normal air breathing result in any improvement in the signs of multiple sclerosis? Search Terms: Hyperbaric oxygenation, multiple sclerosis
The Study: Double-blinded concealed randomised controlled trial with intention-to-treat. Patients were admitted to the study with clinically definite MS, a disability score of 3 to 7.5 and no contra-indications to compression. Control group (N = 41; 35 analysed): Sham hyperbaric exposures daily for 20 days, then 2 sessions 1 month later and 5 sessions monthly thereafter. Breathed 12.5% oxygen at 1.75ATA to mimic air breathing for 90 minutes each session. Experimental group (N = 41; 37 analysed): Schedule as above, but 100% oxygen at 1.75ATA.
The Evidence:
| Outcome | Time to Outcome | Air group | HBO group | Relative risk reduction | Absolute risk reduction | NNT |
| Improved disability score | 6 months | 0.057 | 0.054 | 5% | 0.003 | 333 |
| 95% CI: | -100% to 100% | -0.103 to 0.109 | NNT9 to INF NNH10 to INF | |||
| Improved functional assessment | 6 months | 0.314 | 0.324 | -3% | -0.010 | -100 |
| 95% CI: | -72% to 65% | -0.225 to 0.205 | NNT5 to INF NNH4 to INF | |||
| Exacerbation of MS | 6 months | 0.114 | 0.081 | 29% | 0.033 | 30 |
| 95% CI: | -91% to 100% | -0.104 to 0.170 | NNT6 to INF NNH10 to INF |
Comments: 1. High level of methodological rigor, with good blinding and sham treatment. 2. Matched pair design analysed appropriately. 3. Most patients reported (blind) that they felt they received air treatment due to lack of improvement. 4. Random samples of trial patients did not show a difference in MRI appearance or evoked potentials. 5. Some non-significant improvement in bladder symptoms.
Expiry date: January 2015 References: 1. Harpur GD, Suke R, Bass BH, Bass MJ, Bull SB, Reese L, Noseworthy JH, Rice GP, Ebers GC. Hyperbaric oxygen therapy in chronic stable multiple sclerosis: double-blind study. Neurology 1986; 36:988-991.
