Drewry
Heliox recompression for the treatment of DCI may result in fewer patients requiring multiple recompressions.
| Clinical Bottom Line: |
| 1. Fewer patients in the heliox group required more than one recompression due to incomplete resolution and /or persistence of symptoms. |
Appraised by: Mike Bennett, Dept. of Diving and Hyperbaric Medicine, Prince of Wales Hospital Sydney; Monday, 23 November, 1998
Clinical Scenario: A patient presenting with decompression illness after air diving. Three-part Question: In patients suffering with decompression illness, does the application of 50/50 heliox at 2.8 ATA, compared to standard 100% oxygen treatment tables, result in any reduction in the proportion with incomplete resolution and/or return of symptoms? Search Terms: Hyperbaric oxygenation, decompression illness.
The Study: Double-blinded concealed randomised controlled trial intention-to-treat unknown. Recreational air divers with diagnosis of decompression illness. Control group (N = 31; 31 analysed): Recompression on a standard US Navy Table 6 to 2.8ATA with 100% oxygen breathing periods. Experimental group (N = 25; 25 analysed): Recompression to 2.8ATA, but substitution of 50% oxygen, 50%helium as breathing mixture.
The Evidence:
| Outcome | Time to Outcome | 100% oxygen | Heliox | Relative risk reduction | Absolute risk reduction | Number needed to treat |
| Required multiple recompression | 1 year | 0.65 | 0.36 | 44% | 0.285 | 4 |
| 95% CI | 5% to 83% | 0.03 to 0.54 | 2 to 31 |
Comments: 1. 18 of 88 enrolled patients subsequently withdrawn due to protocol breach. 2. Interim report only in abstract. 3. No results published for absolute rate of treatment success.
Expiry date: December 2021. References: 1. Drewry A, Gorman DF. A progress report on the prospective randomised double blind controlled study of oxygen and oxygen-helium in the treatment of air-diving decompression illness. Undersea and Hyperbaric Medicine Supplement 1994; 21:98.
