title: Long-term monitoring of oxygen saturation at altitude can be useful in predicting the subsequent development of moderate-to-severe acute mountain sickness.
abstract: OBJECTIVE
  The use of pulse oximetry (Spo2) to identify subjects susceptible to acute mountain sickness (AMS) is the subject of debate. To obtain more reliable data, we monitored Spo2 for 24 hours at altitude to investigate the ability to predict impending AMS.
  
  
  METHODS
  The study was conducted during the climb from Alagna (1154 m) to Capanna Regina Margherita (4559 m), with an overnight stay in Capanna Gnifetti (3647 m). Sixty subjects (11 women) were recruited. Each subject was fitted with a 24-hour recording finger pulse oximeter. The subjects rode a cable car to 3275 m and climbed to 3647 m, where they spent the night.
  
  
  RESULTS
  In the morning, 24 subjects (6 women) had a Lake Louise Questionnaire score (LLS) ≥ 3 (AMS(+)), and 15 subjects (4 women) exhibited moderate-to-severe disease (LLS ≥ 5 = AMS(++)). At Alagna, Spo2 did not differ between the AMS(-) and AMS(+) subjects. At higher stations, all AMS(+) subjects exhibited a significantly lower Spo2 than did the AMS(-) subjects: at 3275 m, 85.4% vs 87.7%; resting at 3647 m, 84.5% vs 86.4%. The receiver operating characteristics curve analysis resulted in a rather poor discrimination between the AMS(-) subjects and all of the AMS(+) subjects. With the cutoff LLS ≥ 5, the sensitivity was 86.67%, the specificity was 82.25%, and the area under the curve was 0.88 (P < .0001) for Spo2 ≤ 84% at 3647 m.
  
  
  CONCLUSIONS
  We conclude that AMS(+) subjects exhibit a more severe and prolonged oxygen desaturation than do AMS(-) subjects starting from the beginning of altitude exposure, but the predictive power of Spo2 is accurate only for AMS(++).
authors.affiliation: Biomedical Sport Studies Center, University of Ferrara, Ferrara, Italy (Drs Mandolesi, Avancini, Bernardi, Pomidori, and Cogo).
authors.forename: Gaia
authors.initials: G
authors.lastname: Mandolesi
authors.affiliation: Biomedical Sport Studies Center, University of Ferrara, Ferrara, Italy (Drs Mandolesi, Avancini, Bernardi, Pomidori, and Cogo).
authors.forename: Giovanni
authors.initials: G
authors.lastname: Avancini
authors.affiliation: Department of Experimental Medicine, University of Milano Bicocca, Milano, Italy (Dr Bartesaghi).
authors.forename: Manuela
authors.initials: M
authors.lastname: Bartesaghi
authors.affiliation: Biomedical Sport Studies Center, University of Ferrara, Ferrara, Italy (Drs Mandolesi, Avancini, Bernardi, Pomidori, and Cogo).
authors.forename: Eva
authors.initials: E
authors.lastname: Bernardi
authors.affiliation: Biomedical Sport Studies Center, University of Ferrara, Ferrara, Italy (Drs Mandolesi, Avancini, Bernardi, Pomidori, and Cogo).
authors.forename: Luca
authors.initials: L
authors.lastname: Pomidori
authors.affiliation: Biomedical Sport Studies Center, University of Ferrara, Ferrara, Italy (Drs Mandolesi, Avancini, Bernardi, Pomidori, and Cogo). Electronic address: annalisa.cogo@unife.it.
authors.forename: Annalisa
authors.initials: A
authors.lastname: Cogo
mesh_terms: D000328:Adult; D000532:Altitude Sickness / Q000453:epidemiology / Q000503:physiopathology*; D005260:Female; D006339:Heart Rate; D006801:Humans; D000860:Hypoxia / Q000453:epidemiology / Q000209:etiology / Q000503:physiopathology*; D007558:Italy / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D008991:Monitoring, Physiologic; D009051:Mountaineering / Q000706:statistics & numerical data; D010092:Oximetry; D012720:Severity of Illness Index
keywords: Lake Louise score; hypoxia; pulse oximetry