[Comment] High-altitude populations need special considerations for COVID-19


The atmospheric pressure that decreases with altitude affects lung physiology. However, these changes in physiology are not usually considered in ventilator design and testing. We argue that high altitude human populations require special attention to access the international supply of ventilators.
Humans are naturally adapted to live at low altitude. Yet, ~2% of the world’s population permanently live at altitudes above 2500 meters1. The majority of these populations live in areas that are either poor, such as Ethiopia, Ecuador and Bolivia, or highly controlled, such as Tibet1. The small market size and low economic power of these regions have left them aside in the design of biomedical equipment, which usually does not consider their special environmental conditions and physiological adaptations.

Worldwide, there is a shortage of many goods including intensive care unit (ICU) beds, facemasks, and ventilators due to the COVID-19 pandemic2. This shortage has led to an international “stock market”-like process of bidding for these goods, in which many countries are left at an extreme disadvantage3. Several international organizations, including the International Monetary Fund, the World Bank, and others, have been encouraged to provide loans to developing countries, but access to these goods is an issue that goes beyond money. Many countries have enacted export restrictions, and small orders are usually rejected to give preference to large purchases from powerful nations3. This reduces the capability of less-affluent nations in both treating COVID-19 patients and preventing the further spread of the disease.

Diverse pathological mechanisms in COVID-19 are under investigation, and respiratory symptoms predominate in the clinic. Physiologically, SARS-COV-2 cell entry is dependent on the cellular expression of ACE2 and TMPRSS2, and SARS-COV-2 likely binds to, and replicates in epithelial cells after entering the nasal cavity4. SARS-CoV-2 then spreads from the nasal cavity into the lungs where it primarily infects ciliated epithelial cells that line the conducting airways. As ACE2 expression and receptors are also found in cells outside of the lungs5 and COVID-19 patients have been reported to suffer from non-lung-related illness6, it is likely that SARS-CoV-2 infection is not limited to the nasal cavity and lungs. However, the majority of COVID-19 related deaths are caused by pulmonary illness. Therefore, the lungs are the primary focus of COVID-19 treatment efforts.

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