|
1. Dry diving produces
fewer bubbles than wet diving. |
Citation:
Dujic Z, Palada I, Valic Z, Duplancic D, Obad A, Wisløff U, Brubakk A: Exogenous
nitric oxide and bubble formation in divers. Med Sci Sports Exerc. 2006
Aug;38(8):1432-5.
Lead author's name and e-mail: Zeljko Dujic, zdujic@bsb.mefst.hr
Three-part Clinical Question: Among
divers, would a short lasting NO-donor, nitroglycerine, reduce bubble formation
after standard dives and decompression in man?
Search Terms: Decompression Illness, Nitric Oxide, Diving
The Study:
Non-blinded randomised trial with intention-to-treat.
The Study Patients: 16 experienced divers. All fit and well.
Control groups (N =16; 16 analysed): 10 Wet divers, 30 msw, swimming for
500 m. Bottom time 30 min with 3 min safety stop at 3 msw. 6 Dry divers, 18 msw,
bottom time 75 min with stop at 3 msw for 7 minutes.
Experimental groups (N =16; 16 analysed): As above preceded by 0.4 mg of
nitroglycerine oral spray 30 min before diving.
The Evidence:
|
Measure |
Control Group |
Nitroglycerine Group |
Difference |
95% CI |
||
|
Mean |
SD |
Mean |
SD |
|||
|
Wet dive (bubbles/cm²) N = 10 |
0.87 |
1.3 |
0.32 |
0.7 |
0.55 |
-0.43 to 1.53 |
|
Dry dive (bubbles/cm²) N = 6 |
0.12 |
0.23 |
0.03 |
0.03 |
0.09 |
-0.12 to 0.30 |
|
|
Wet divers N=10 |
Dry divers N=6 |
|
|||
|
Wet vs. dry dive (bubbles/cm²) |
0.87 |
1.3 |
0.12 |
0.23 |
0.75 |
-0.42 to 1.92 |
Comments:
1. The allocation to wet versus dry diving was randomised, but all divers then
did the control dive followed by the nitroglycerine
dive.
2. Our table reflects an independent t-test for the significance of the
difference for the NO/no-NO comparisons. The authors used a paired t-test for
these sequential dives and reported a P-value of 0.04 (wet dives) and 0.05 (dry
dives).
3. Results may not extrapolate to all divers - only divers with "considerable
experience of air and oxygen diving" were eligible.
4. No side-effects measured.
Appraised by: Ing Han Gho and Mike Bennett,
Prince of Wales Hospital, Sydney; Friday, 1 August 2008
Email: m.bennett@unsw.edu.au
Kill or Update By: August 2009