Abstract

BOTELLA DE MAGLIA, J.; REAL SORIANO, R.  and  COMPTE TORRERO, L.. Arterial oxygen saturation during ascent of a mountain higher than 8,000 meters. Med. Intensiva [online]. 2008, vol.32, n.6, pp.277-281. ISSN 0210-5691.

Background. Arterial oxygen saturation (SaO₂) diminishes with altitude. Aim. To know the values of SaO₂ in healthy mountaineers during the ascent of a mountain higher than 8,000 metres. Method. On occasion of an expedition to Gasherbrum II (8,035 m), SaO₂ at rest was measured by pulse oxymetry during the approach march, in the base camp (on day one and one month later), in camps II and III, during the assault at 7,500 m and on the summit. Results. During the approach march, the SaO₂ in Paiju (3,365 m) was 92.9 ± 1.4% and in Gore II (4,250 m) 85.0 ± 4.3%. In the base camp (5,200 m) it was 78.4 ± 9.5% on the first day and 87.4 ± 3.0% one month later (p < 0.007). In camp II (6,500 m) it was 72.7 ± 6.7%. In camp III (7,000 m) it was 68.0 ± 9.3% (recorded on 21 asymptomatic climbers). At this altitude a SaO₂ of 40% was recorded during sleep in an asymptomatic subject, apparently without apnoeic crises. During the assault at 7,500 m, SaO₂ was 60.5 ± 13.5% (measured on 4 climbers). On the summit (8,035 m) the SaO₂ of two subjects was 84% and 88%, respectively. Conclusion. During expeditions to mountains higher than 8,000 metres, mountaineers have extremely low values of SaO₂, similar to those of patients with severe respiratory failure. SaO₂ increases progressively with acclimatization. SaO₂ on the summit could have been relatively high, probably because of hyperventilation.

Keywords : arterial oxygen saturation; high altitude; mountaineering.

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