Pre-compression exercise decreased bubble counts following compressed air breathing
Clinical Bottom Line
1. Pre-'dive' exercise reduces bubble grade after diving.
Citation/s:1. Blatteau J-E, Boussuges A, Castagna, Gempp E, Pontier J-N, Robinet OC, Galland F-M. A 2-hours pre-dive aerobic exercise decreases bubble formation after diving. ICHM-EUBS Proceedings 2005, Desola J (Ed).Barcelona7-10 September 2005.

Three-part Clinical Question: For individuals breathing compressed air, does exercise before exposure decrease post-exposure bubble formation?
Search Terms: gas nuclei, decompression illness, venous gas embolism

The Study:Non-blinded randomised crossover trial with intention-to-treat.
The Study Patients: Healthy volunteer military divers.
Control group (Two groups of N = 16; 16 analysed): No exercise or diving for two days before exposure to 400kPa (approx 30metres) for 30 minutes breathing air in a hyperbaric chamber.
Experimental group (Two groups of N = 16; 16 analysed): As above but two exercise regimens. Either 45 minutes of endurance running at about 70% of maximum theoretical heart rate starting 2 hours before exposure, or 40 minutes at the heart rate corresponding to ventilatory threshold.

The Evidence:

Non-Event Outcomes
Time to outcome/s
Control groups
Exercise groups
P-value
Peak bubble grade (45 minutes exercise)
60 minutes
Median 1 (IQR 0 to 2)
Median 0 (IQR 0 to 1)
0.004
Peak bubble grade (40 minutes exercise)
60 minutes


0.023
Comments:
1. Confusing study design involving crossover and two different exercise regimens. We have assumed that no individuals were crossed between the two exercise regimens. Difference in exercise intensity is not clear.
2. Data given for 45 minute group comparison only.
3. Non-peer reviewed short report in conference proceedings.

Appraised by: Sean Hopson, Mike Bennett, POWH, Sydney ; Friday, 1 September 2006Email: sean@thegasman.org
Kill or Update By: September 2007




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