Background

Survival from avalanche burial is dependent on time to extraction, breathing ability, air pocket oxygen content, and avoiding rebreathing of carbon dioxide (CO₂). Mortality from asphyxia increases rapidly after burial. Rescue services often arrive too late. Our objective was to evaluate the physiological effects of providing personal air supply in a simulated avalanche scenario as a possible concept to delay asphyxia. We hypothesize that supplemental air toward victim’s face into the air pocket will prolong the window of potential survival.

Methods

A prospective randomized crossover experimental field study enrolled 20 healthy subjects in Hemsedal, Norway in March 2019. Subjects underwent in randomized order two sessions (receiving 2 litres per minute of air in front of mouth/nose into the air pocket or no air) in a simulated avalanche scenario with extensive monitoring serving as their own control.

Results

A significant increase comparing Control vs Intervention were documented for minimum and maximum end-tidal CO₂ (EtCO₂), respiration rate, tidal volume, minute ventilation, heart rate, invasive arterial blood pressures, but lower peripheral and cerebral oximetry. Controls compared to Intervention group subjects had a lower study completion rate (26% vs 74%), and minutes in the air pocket before interruption (13.1 ± 8.1 vs 22.4 ± 5.6 vs), respectively.

Conclusions

Participants subject to simulated avalanche burial can maintain physiologic parameters within normal levels for a significantly longer period if they receive supplemental air in front of their mouth/nose into the air pocket. This may extend the time for potential rescue and lead to increased survival.

中文翻译：

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为雪崩受害者提供补充空气的生理效应。一项随机试验

背景

雪崩掩埋后的生存取决于提取时间、呼吸能力、气袋中的氧气含量以及避免重新吸入二氧化碳 (CO ₂ )。埋葬后窒息死亡率迅速增加。救援服务往往来得太晚。我们的目标是评估在模拟雪崩场景中提供个人空气供应的生理效应，作为延迟窒息的可能概念。我们假设向受害者面部补充空气进入气囊将延长潜在生存的窗口。

方法

一项前瞻性随机交叉实验实地研究于 2019 年 3 月在挪威 Hemsedal 招募了 20 名健康受试者。受试者按随机顺序在一个模拟雪崩场景，广泛监控作为他们自己的控制。

结果

在最小和最大呼气末 CO ₂ (EtCO ₂ )、呼吸频率、潮气量、分钟通气量、心率、有创动脉血压方面记录了显着增加，但外周血氧饱和度和脑血氧饱和度降低。与干预组受试者相比，对照组的研究完成率较低（26% 对 74%），中断前在气囊中的分钟数（分别为 13.1 ± 8.1 对 22.4 ± 5.6 对）。

结论

接受模拟雪崩掩埋的参与者如果在他们的嘴/鼻子前接受补充空气进入气袋，他们的生理参数可以在更长的时间内保持在正常水平。这可能会延长潜在救援的时间并提高生存率。