Effect of oxygen-breathing during a decompression-stop on bubble-induced platelet activation after an open-sea air dive: oxygen-stop decompression

Abstract

Purpose: We highlighted a relationship between decompression-induced bubble formation and platelet micro-particle (PMP) release after a scuba air-dive. It is known that decompression protocol using oxygen-stop accelerates the washout of nitrogen loaded in tissues. The aim was to study the effect of oxygen deco-stop on bubble formation and cell-derived MP release.

Methods: Healthy experienced divers performed two scuba-air dives to 30 msw for 30 min, one with an air deco-stop and a second with 100% oxygen deco-stop at 3 msw for 9 min. Bubble grades were monitored with ultrasound and converted to the Kisman integrated severity score (KISS). Blood samples for cell-derived micro-particle analysis (AnnexinV for PMP and CD31 for endothelial MP) were taken 1 h before and after each dive.

Results: Mean KISS bubble score was significantly lower after the dive with oxygen-decompression stop, compared to the dive with air-decompression stop (4.3 ± 7.3 vs. 32.7 ± 19.9, p < 0.001). After the dive with an air-breathing decompression stop, we observed an increase of the post-dive mean values of PMP (753 ± 245 vs. 381 ± 191 ng/μl, p = 0.003) but no significant change in the oxygen-stop decompression dive (329 ± 215 vs. 381 +/191 ng/μl, p = 0.2). For the post-dive mean values of endothelial MP, there was no significant difference between both the dives.

Conclusions: The Oxygen breathing during decompression has a beneficial effect on bubble formation accelerating the washout of nitrogen loaded in tissues. Secondary oxygen-decompression stop could reduce bubble-induced platelet activation and the pro-coagulant activity of PMP release preventing the thrombotic event in the pathogenesis of decompression sickness.