Gouin Emmanuel, Dugrenot Emmanuel, Gardette Bernard
University of Brest, Laboratory ORPHY EA 4324, Brest, France.
Divers Alert Network, Durham, NC, USA.
Diving Hyperb Med. 2025 Jun 30;55(2):203-210. doi: 10.28920/dhm55.2.203-210.
Extreme deep technical diving presents significant physiological challenges. While procedures often blend elements from both recreational and commercial diving, many remain empirical and unvalidated for this purpose. The rise of closed-circuit rebreathers has reduced gas cost and logistical barriers, enabling more divers to reach unprecedented depths. This study, based on the experience of deep divers, explores the limits of extreme-depth diving and the strategies developed to overcome them.
Eight rebreather divers (one female, seven males) with experience beyond 200 metres depth were interviewed regarding their preparation, planning, and execution of such dives. The dive profiles of their deepest dives were analysed.
All were highly experienced technical divers. The median maximal depth was 227 [209-302] metres, with a median total dive time of 290 [271-395] minutes. The gas density of the trimix mixture, oxygen exposure, and ascent rate consistently exceeded current recommendations. High pressure nervous syndrome did not appear to be a major limiting factor, whereas decompression posed greater challenges. Three divers experienced decompression sickness following their deepest dives, highlighting the uncertainty around decompression procedures.
These dives require rigorous preparation, robust support systems, equipment modifications, and perfect skills to reduce risks, which remain excessively high. Data are lacking to validate current practices. Decompression procedures must be adapted for these demanding mixed-gas dives, which are inevitably prolonged. A dry underwater habitat could improve decompression tolerance. The role of hydrogen as a breathing gas remains uncertain and still needs to be clarified, but some consider it a promising avenue for further exploration.
极限深度技术潜水带来了重大的生理挑战。虽然潜水程序通常融合了休闲潜水和商业潜水的元素，但许多程序在此目的上仍属经验性且未经验证。闭路循环呼吸器的兴起降低了气体成本和后勤障碍，使更多潜水员能够达到前所未有的深度。本研究基于深度潜水员的经验，探索极限深度潜水的极限以及为克服这些极限而制定的策略。
对8名有超过200米深度潜水经验的循环呼吸器潜水员（1名女性，7名男性）就此类潜水的准备、计划和执行情况进行了访谈。分析了他们最深潜水的潜水剖面。
所有潜水员都是经验丰富的技术潜水员。最大深度中位数为227[209 - 302]米，总潜水时间中位数为290[271 - 395]分钟。 Trimix混合气的气体密度、氧气暴露量和上升速度始终超过当前建议值。高压神经综合征似乎不是主要限制因素，而减压带来了更大挑战。3名潜水员在最深潜水后出现减压病症状，凸显了减压程序的不确定性。
这些潜水需要严格的准备、强大的支持系统、设备改装和精湛的技能以降低风险，而目前风险仍然过高。缺乏数据来验证当前的做法。减压程序必须针对这些要求苛刻的混合气潜水进行调整，因为此类潜水不可避免地会延长时间。干式水下栖息地可能会提高减压耐受性。氢气作为呼吸气体的作用仍不确定，仍需进一步阐明，但一些人认为这是一个有前景的进一步探索途径。
