Brebeck
Breathing nitrox28 (28% oxygen) while scuba diving may produce fewer bubbles in the hour after surfacing
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1. Weak evidence there were fewer bubbles after breathing nitrox |
Citation/s: 1. Brebeck AK, Deussen A, Range U, Balestra C, Cleveland S, Schipke JD. Beneficial effect of enriched air nitrox on bubble formation during scuba diving. An open-water study. Journal of sports sciences. 2018 Mar 19;36(6):605-12
Lead author's name and fax: Anne-Kathrin Brebeck. Contact Jochen Schipke j.schipke@gmx.org
Three-part Clinical Question:For scuba diving, does breathing an oxygen reduced air mix compared to air result in fewer detectable velous bubbles after diving?
Search Terms: Venous gas embolism; doppler; decompression
The Study:
Double-blinded concealed randomised controlled trial with intention-to-treat.
The Study Patients: Adult volunteer divers
Control group (N = 54; 54 analysed): Air breathing during a standard dive to 24 msw for 62 minutes
Experimental group (N = 54; 54 analysed): Enriched air breathing of 28% oxygen (nitrox28) for the same dive.
The Evidence:
Outcome |
Time to Outcome |
Air |
Nitrox |
Relative Risk Reduction |
Absloute Risk Reduction |
NNT |
No bubbles detected |
60 mins |
0.11 |
0.07 |
36% |
0.04 |
25 |
95% CIs: |
-62% to 100% |
-0.07 to 0.15 |
NNT = 7 to INF NNH = 15 to INF | |||
Measure |
Air Group |
Nitrox Group |
Difference |
95% CI | ||
|
Mean |
SD |
Mean |
SD | |||
|
Bubbles detected per minute |
30 |
32 |
16 |
16 |
14 |
-108 to 136 |
Comments:
1. Trial powered for one-sided statistical testing for a 25% reduction in subclavian bubbles with nitrox. The figure for that comparison is not given.
2. The authors exhaustively analyzed the data for differences between vein sites and time with few important differe nces noted.
3. There were more bubbles detected in females than males
4. The authors report in the abstract, but not in results that "more bubbles were
counted in the air-group than in the air28-group (pooled vein: early: 1845 vs. 948; P = 0.047. One may get the feeling the authors are stretching for meaning here. 5. Authors measured bubbles at three differnt sites - subclavian, jugular and femoral
Appraised by: Michael Bennett m.bennett@iunsw. edu.au ; Monday, 13 April 2020
Kill or Update By:April 2022
