Investigating carbon monoxide exposure on Denali

Area of Science:

• Environmental Health
• Altitude Medicine
• Toxicology

Background:

• Acute mountain sickness (AMS) is a common concern for high-altitude climbers.
• Carbon monoxide (CO) exposure is a potential risk in enclosed environments at altitude.
• Understanding factors contributing to AMS and CO exposure is crucial for climber safety.

Purpose of the Study:

• To investigate the relationship between elevated carboxyhemoglobin (COHb) levels and AMS at 4300 m.
• To explore associations between COHb levels, AMS, and climber characteristics/behaviors.
• To identify potential risk factors for CO exposure and AMS in a high-altitude mountaineering context.

Main Methods:

• 146 climbers at 4300 m on Denali were assessed for AMS using the Lake Louise questionnaire.
• Serum cooximetry measured carboxyhemoglobin (COHb) levels.
• Data on stove practices, climbing behaviors, and prophylactic medication use were collected and analyzed using nonparametric statistics.

Main Results:

• No significant relationship was found between positive CO exposure and AMS criteria.
• Climbers descending the mountain were 3.6 times more likely to have positive CO exposure and had significantly higher COHb levels.
• Increased stove operation time was significantly linked to climbers meeting AMS criteria.

Conclusions:

• The study did not establish a significant link between AMS symptoms and CO exposure, possibly due to low AMS prevalence and limited statistical power.
• Descending climbers face a higher risk of CO exposure.
• Prolonged stove use is associated with AMS symptoms in high-altitude climbers.