Effect of a single, open-sea, air scuba dive on human micro- and macrovascular function.
OBJECTIVE
Previous studies have shown that bubble formation induced endothelial damage on conduit arteries. We aim to evaluate the effect of diving on microvascular and macrovascular function.


METHODS
Nine divers took part in a SCUBA dive at 30 msw (400 kPa), for 30 min of bottom time. Pre- and post-dive, they underwent an assessment of endothelial-dependent (acetylcholine) and endothelial-independent (sodium nitroprusside) microvascular function (laser Doppler flowmetry), as well as endothelial-dependent (flow-mediated dilation) and endothelial-independent (nitroglycerin-mediated dilation) function. Bubble grades were monitored with Doppler according to the Spencer grade.


RESULTS
The mean KISS bubble score ranged from 21.10 ± 4.7 at rest to 55.03 ± 8.8 after knee flexion. The increase in cutaneous vascular conductance elicited by either acetylcholine (25.34 ± 6.71 to 7.63 ± 1.25 %, p = 0.021) or sodium nitroprusside (35.24 ± 8.75 to 7.61 ± 1.86 %, p = 0.017) was significantly reduced after diving. Similarly, both flow-mediated dilation (10.8 ± 0.9 to 5.4 ± 1.5 %, p = 0.002) and nitroglycerin-mediated dilation (15 ± 1.1 to 6.5 ± 1.6 %, p = 0.002) were also significantly decreased. There were no correlations between vascular parameters and bubble formation.


CONCLUSIONS
There appears to be a reduction in endothelium-dependent and endothelium-independent, macro- and microvascular function associated with diving. Our results suggest that in the process of vascular dysfunction during diving, functional changes in the vessel wall may not be limited to the endothelium and may be mediated by alterations in vascular smooth muscle.
Orphy Laboratory, Université de Bretagne Occidentale, 29200, Brest, France, lambrechtskate@hotmail.com.
Kate
K
Lambrechts
Jean-Michel
JM
Pontier
Costantino
C
Balestra
Aleksandra
A
Mazur
Qiong
Q
Wang
Peter
P
Buzzacott
Michael
M
Theron
Jacques
J
Mansourati
François
F
Guerrero
D000328:Adult; D001916:Brachial Artery / Q000502:physiology; D016022:Case-Control Studies; D003664:Decompression; D004242:Diving / Q000502:physiology*; D006801:Humans; D017078:Laser-Doppler Flowmetry; D007866:Leg / Q000098:blood supply; D008297:Male; D008833:Microcirculation; D008875:Middle Aged; D009792:Oceans and Seas; D012039:Regional Blood Flow; D012867:Skin / Q000098:blood supply; D014664:Vasodilation