Diving and Hyperbaric Department, French Navy Diving School, BP 311, 83800 Toulon, France.
ORPHY Laboratory, PHYPODE Project, Université de Bretagne Occidentale, Brest, France; School of Sports Science, Exercise and Health, The University of Western Australia, Crawley, Western Australia 6009, Australia.
Nitric Oxide. 2014 May 30;39:29-34. doi: 10.1016/j.niox.2014.04.005. Epub 2014 Apr 18.
Previous studies have highlighted a decreased exhaled nitric oxide concentration (FE NO) in divers after hyperbaric exposure in a dry chamber or following a wet dive. The underlying mechanisms of this decrease remain however unknown. The aim of this study was to quantify the separate effects of submersion, hyperbaric hyperoxia exposure and decompression-induced bubble formation on FE NO after a wet dive.
Healthy experienced divers (n=31) were assigned to either (i) a group making a scuba-air dive (Air dive), (ii) a group with a shallow oxygen dive protocol (Oxygen dive) or (iii) a group making a deep dive breathing a trimix gas mixture (deep-dive). Bubble signals were graded with the KISS score. Before and after each dive FE NO values were measured using a hand-held electrochemical analyzer.
There was no change in post-dive values of FE NO values (expressed in ppb=parts per billion) in the Air dive group (15.1 ± 3.6 ppb vs. 14.3 ± 4.7 ppb, n=9, p=0.32). There was a significant decrease in post-dive values of FE NO in the Oxygen dive group (15.6 ± 6 ppb vs. 11.7 ± 4.7 ppb, n=9, p=0.009). There was an even more pronounced decrease in the deep dive group (16.4 ± 6.6 ppb vs. 9.4 ± 3.5 ppb, n=13, p<0.001) and a significant correlation between KISS bubble score >0 (n=13) and percentage decrease in post-dive FE NO values (r=-0.53, p=0.03).
Submersion and hyperbaric hyperoxia exposure cannot account entirely for these results suggesting the possibility that, in combination, one effect magnifies the other. A main finding of the present study is a significant relationship between reduction in exhaled NO concentration and dive-induced bubble formation. We postulate that exhaled NO concentration could be a useful index of decompression severity in healthy human divers.
先前的研究已经表明，在干式高压舱或湿式潜水后，潜水员的呼气一氧化氮浓度（FE NO）会降低。然而，这种降低的潜在机制尚不清楚。本研究的目的是量化浸没、高压高氧暴露和减压引起的气泡形成对湿式潜水后 FE NO 的单独影响。
健康有经验的潜水员（n=31）被分配到以下三组之一：（i）进行水肺潜水空气组（Air dive），（ii）进行浅水氧气潜水协议组（Oxygen dive），或（iii）进行深潜呼吸混合气体组（深潜组）。用 KISS 评分对气泡信号进行分级。在每次潜水前后，使用手持式电化学分析仪测量 FE NO 值。
在 Air dive 组中，潜水后 FE NO 值（以 ppb=十亿分之一表示）没有变化（15.1 ± 3.6 ppb 与 14.3 ± 4.7 ppb，n=9，p=0.32）。在 Oxygen dive 组中，潜水后 FE NO 值显著降低（15.6 ± 6 ppb 与 11.7 ± 4.7 ppb，n=9，p=0.009）。在深潜组中，下降更为明显（16.4 ± 6.6 ppb 与 9.4 ± 3.5 ppb，n=13，p<0.001），并且 KISS 气泡评分>0（n=13）与潜水后 FE NO 值降低百分比之间存在显著相关性（r=-0.53，p=0.03）。
浸没和高压高氧暴露不能完全解释这些结果，这表明，这些结果可能是一种影响放大另一种影响的可能性。本研究的一个主要发现是呼气一氧化氮浓度降低与潜水引起的气泡形成之间存在显著关系。我们推测，呼气一氧化氮浓度可能是健康人类潜水员减压严重程度的有用指标。
