Shi Lu, Zhang Yan-Meng, Tetsuo Katsuura, Shi Zhong-Yuan, Fang Yi-Qun, Denoble Petar J, Li Yang-Yang
Aerosp Med Hum Perform. 2017 Dec 1;88(12):1088-1093. doi: 10.3357/AMHP.4912.2017.
Experience with commercial heliox diving at high altitude is limited. The purpose of this study was to evaluate the effects of acute high-altitude exposure on fitness to dive and the safety of decompression after heliox diving while using U.S. Navy heliox decompression tables with Cross correction.
Four professional male divers were consecutively decompressed in a hypo- and hyperbaric chamber to altitudes of 3000 m (9842.5 ft), 4000 m (13,123.4 ft), and 5200 m (17,060.4 ft) during the 8-d study. The dive profiles tested were to 30 m (98.4 ft) for 60 min at all three altitudes and, in addition, a dive to 50 m (164 ft) for 60 min at 5200 m altitude. The decompression followed the U.S. Navy heliox decompression table. The safety of decompression was evaluated by precordial Doppler venous gas emboli (VGE) monitoring during the decompression stages and postdive monitoring of the divers for symptoms of decompression sickness (DCS). Effects of altitude exposure were measured as subjective rating and EEG signs of sleepiness and fatigue, clinical symptoms of high altitude disease, and fitness to dive.
A total of 24 person-dives were conducted. There were no VGE detected during the decompression and no postdive symptoms of decompression illness. Both the EEG findings and subjective evaluation indicated increased sleepiness and fatigue at 3000 m, 4000 m, and 5200 m, all compared with the sea level baseline. During the diving phase, both the EEG findings and subjective evaluation scores returned to the baseline and the divers successfully completed diving.
Diving at high altitude with a short acclimatization period appears safe despite divers exhibiting clinical symptoms and EEG signs of impairment by hypoxia at high altitude. Despite a small number of dives, the results of this study indicate that our application of U.S. Navy standard heliox decompression tables with Cross correction is effective and could be used for underwater constructions up to 5200 m altitude, with due caution.Shi L, Zhang Y, Tetsuo K, Shi Z, Fang Y, Denoble PJ, Li Y. Simulated high altitude helium-oxygen diving. Aerosp Med Hum Perform. 2017; 88(12):1088-1093.
高海拔地区商业氦氧混合气潜水的经验有限。本研究的目的是评估急性高海拔暴露对潜水适应性的影响以及使用美国海军氦氧混合气减压表并进行交叉校正后氦氧混合气潜水减压的安全性。
在为期8天的研究中，4名专业男性潜水员在高低压舱中依次减压至3000米（9842.5英尺）、4000米（13123.4英尺）和5200米（17060.4英尺）的高度。在所有三个高度测试的潜水剖面均为下潜至30米（98.4英尺）并停留60分钟，此外，在5200米高度还有一次下潜至50米（164英尺）并停留60分钟的潜水。减压过程遵循美国海军氦氧混合气减压表。通过在减压阶段进行心前区多普勒静脉气体栓塞（VGE）监测以及潜水后对潜水员进行减压病（DCS）症状监测来评估减压的安全性。通过主观评分以及嗜睡和疲劳的脑电图征象、高原病的临床症状和潜水适应性来衡量高海拔暴露的影响。
共进行了24人次潜水。减压过程中未检测到VGE，潜水后也没有减压病症状。脑电图结果和主观评估均表明，与海平面基线相比，在3000米、4000米和5200米高度时嗜睡和疲劳增加。在潜水阶段，脑电图结果和主观评估分数均恢复到基线水平，潜水员成功完成潜水。
尽管潜水员在高海拔地区表现出临床症状和缺氧导致的脑电图损伤征象，但在短时间适应期后进行高海拔潜水似乎是安全的。尽管潜水次数较少，但本研究结果表明，我们应用经交叉校正的美国海军标准氦氧混合气减压表是有效的，可用于海拔高达5200米的水下作业，但需谨慎使用。
施L，张Y，哲夫K，施Z，方Y，德诺布尔PJ，李Y。模拟高海拔氦氧潜水。航空航天医学与人类表现。2017；88（12）：1088 - 1093。
