Annalisa Cogo, Giuseppe Fiorenzano
COPD patients at altitude S U M M A RY Chronic Obstructive Pulmonary Disease (COPD) is a major health problem because of its high prevalence in the general population. Sometimes COPD patients ask their physicians about the possibility either to travel in mountain regions or to go by plane. The article reviews this possibility analyzing the characteristics of COPD, the high altitude environment, the adaptations of the respiratory system to high altitude and the recommendations for the patients. COPD is characterized by airflow obstruction not fully reversible, in response to exposure to noxious particles (cigarette smoke, professional exposures, pollution) in susceptible subjects. Symptoms of COPD are cough, sputum, progressive dyspnoea. Spirometry confirms the diagnosis and allows to assess the severity of obstruction. At altitude the climate is characterized by a progressive reduction of barometric pressure, with a reduction of inspired fraction of oxygen. Other findings are the decrease of air density, temperature and humidity, and a reduction of allergens and pollutants. In normal subjects, adaptation to high altitude is characterized by hyperventilation, pulmonary vasoconstriction and increased work of breathing. COPD patients have a reduction of the respiratory reserve, with a difficult adaptation to high altitude. The major problem is the gas exchange impairment. In COPD patients it is possible to predict the PaO2 at altitude using spirometry and gas analysis at sea level, so detecting the patients that require oygen supplementation at high altitude or during flights. Inspiration of drier and colder air may be beneficial for patients with mild symptoms, but dangerous for more impaired subjects. To evaluate the possibility for COPD patients to travel at high altitude an individual evaluation is needed, including spirometry, blood gas analysis and walking test. The results may be evaluated depending on: the living altitude, the altitude of destination, the rate of ascent, the duration of stay, the amount of exercise at altitude. Keywords: COPD, altitude, mountaineering, hypoxia, flight
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