%0 Journal Article
%T Physiological Risk Factors of Severe High Altitude Illness: A Prospective Cohort Study
%J American journal of respiratory and critical care medicine
%D 2012
%A Richalet, Jean-Paul
%A Larmignat, Philippe
%A Poitrine, Eric
%A Letournel, Murielle
%A Canouï-Poitrine, Florence
%V 185
%N 2
%P 192-198
%X RATIONALE: An increasing number of persons, exposed to high altitude for leisure, sport or work, may suffer from severe high altitude illness. OBJECTIVES: To assess, in a large cohort of subjects, the association between physiological parameters and the risk of altitude illness and their discrimination ability in a risk prediction model. METHODS: 1326 persons went through a hypoxic exercise test before a sojourn above 4,000m. They were then followed up at high altitude and classified as suffering from severe high altitude illness (SHAI) or not. Analysis was stratified according to acetazolamide use. MEASUREMENTS AND MAIN RESULTS: Severe acute mountain sickness occurred in 314 (23.7%), high altitude pulmonary edema in 22 (1.7%) and high altitude cerebral edema in 13 (0.98%) patients. Among non acetazolamide users (n=917), main factors independently associated with SHAI were previous history of SHAI (adjusted Odds Ratios - aOR=12.82; 95%CI:6.95-23.66; P<0.001), ascent > 400m/day (aOR= 5.89; 95%CI:3.78-9.16; P<0.001), history of migraine (aOR= 2.28; 95%CI:1.28-4.07; P= 0.005), ventilatory response to hypoxia at exercise <0.78 L/min/kg (aOR=6.68; 95% CI:3.83-11.63; P<0.001) and desaturation at exercise in hypoxia ≥22% (aOR= 2.50; 95% CI:1.52-4.11;P<0.001). Last two parameters improved substantially the discrimination ability of multivariate prediction model (C-statistic rose from 0.81 to 0.88, P<0.001). Preventive use of acetazolamide reduced the relative risk of SHAI by 44%. CONCLUSIONS: In a large population of altitude visitors, chemosensitivity parameters (high desaturation and low ventilatory response to hypoxia at exercise) were independent predictors of severe high altitude illness. They improved the discrimination ability of a risk prediction model.<p /> <p>Language: en</p>
%G en
%I American Thoracic Society
%@ 1073-449X
%U http://dx.doi.org/10.1164/rccm.201108-1396OC