Biomarkers as predictors of mortality in critically ill obese patients with COVID-19 at high altitude.

Background: Obesity is a common chronic comorbidity of patients with COVID-19, that has been associated with disease severity and mortality. COVID-19 at high altitude seems to be associated with increased rate of ICU discharge and hospital survival than at sea-level, despite higher immune levels and inflammation. The primary aim of this study was to investigate the survival rate of critically ill obese patients with COVID-19 at altitude in comparison with overweight and normal patients.

Morphological and functional findings in COVID-19 lung disease as compared to Pneumonia, ARDS, and High-Altitude Pulmonary Edema.

Coronavirus disease-2019 (COVID-19) may severely affect respiratory function and evolve to life-threatening hypoxia. The clinical experience led to the implementation of standardized protocols assuming similarity to severe acute respiratory syndrome (SARS-CoV-2). Understanding the histopathological and functional patterns is essential to better understand the pathophysiology of COVID-19 and then develop new therapeutic strategies.

High Altitude Pulmonary Edema, High Altitude Cerebral Edema, and Acute Mountain Sickness: an enhanced opinion from the High Andes - La Paz, Bolivia 3,500 m.

Traveling to high altitudes for entertainment or work is sometimes associated with acute high altitude pathologies. In the past, scientific literature from the lowlander point of view was primarily based on mountain climbing. Sea level scientists developed all guidelines, but they need modifications for medical care in high altitude cities.

Understanding the pathophysiology of typical acute respiratory distress syndrome and severe COVID-19.

Introduction: Typical acute respiratory distress syndrome (ARDS) and severe coronavirus-19 (COVID-19) pneumonia share complex pathophysiology, a high mortality rate, and an unmet need for efficient therapeutics.

Areas Covered: This review discusses the current advances in understanding the pathophysiologic mechanisms underlying typical ARDS and severe COVID-19 pneumonia, highlighting specific aspects of COVID-19-related acute hypoxemic respiratory failure that require attention. Two models have been proposed to describe the mechanisms of respiratory failure associated with typical ARDS and severe COVID-19 pneumonia.

Oxygen therapy limiting peripheral oxygen saturation to 89-93% is associated with a better survival prognosis for critically ill COVID-19 patients at high altitudes.

Patients admitted to the Intensive Care Unit (ICU) with acute hypoxemic respiratory failure automatically receive oxygen therapy to improve inspiratory oxygen fraction (FiO). Supplemental oxygen is the most prescribed drug for critically ill patients regardless of altitude of residence. In high altitude dwellers (i.

The Oxygen Transport Triad in High-Altitude Pulmonary Edema: A Perspective from the High Andes.

Acute high-altitude illnesses are of great concern for physicians and people traveling to high altitude. Our recent article "Acute Mountain Sickness, High-Altitude Pulmonary Edema and High-Altitude Cerebral Edema, a View from the High Andes" was questioned by some sea-level high-altitude experts. As a result of this, we answer some observations and further explain our opinion on these diseases.

Low serum erythropoietin levels are associated with fatal COVID-19 cases at 4,150 meters above sea level.

Previous studies suggested that erythropoietin (EPO) may protect against severe COVID-19-induced injuries, ultimately preventing mortality. This hypothesis is based on the fact that, in addition to promoting the increase in red blood cells, EPO is an anti-inflammatory, anti-apoptotic and protective factor in several non-erythropoietic tissues. Furthermore, EPO promotes nitric oxide production in the hypoxic lung and stimulates ventilation by interacting with the respiratory centers of the brainstem.

Decreased incidence, virus transmission capacity, and severity of COVID-19 at altitude on the American continent.

The coronavirus disease 2019 (COVID-19) outbreak in North, Central, and South America has become the epicenter of the current pandemic. We have suggested previously that the infection rate of this virus might be lower in people living at high altitude (over 2,500 m) compared to that in the lowlands. Based on data from official sources, we performed a new epidemiological analysis of the development of the pandemic in 23 countries on the American continent as of May 23, 2020.

Acute Mountain Sickness, High Altitude Pulmonary Edema, and High Altitude Cerebral Edema: A view from the High Andes.

Background: Travelling to high altitude for entertainment or work is sometimes associated with acute high altitude pathologies. In the past, scientific literature from the lowlanders' point of view was mostly based on mountain climbing. Nowadays, descent is not mandatory in populated highland cities.

Pneumolysis and "Silent Hypoxemia" in COVID-19.

COVID-19 can evolve to a severe lung compromise with life-threatening hypoxemia. The mechanisms involved are not fully understood. Their understanding is crucial to improve the outcomes.

COVID-19 and Pneumolysis Simulating Extreme High-altitude Exposure with Altered Oxygen Transport Physiology; Multiple Diseases, and Scarce Need of Ventilators: Andean Condor's-eye-view.

Background: Critical hypoxia in this COVID-19 pandemic results in high mortality and economic loss worldwide. Initially, this disease' pathophysiology was poorly understood and interpreted as a SARS (Severe Acute Respiratory Syndrome) pneumonia. The severe atypical lung CAT scan images alerted all countries, including the poorest, to purchase lacking sophisticated ventilators.

Coping with hypoxemia: Could erythropoietin (EPO) be an adjuvant treatment of COVID-19?

A very recent epidemiological study provides preliminary evidence that living in habitats located at 2500 m above sea level (masl) might protect from the development of severe respiratory symptoms following infection with the novel SARS-CoV-2 virus. This epidemiological finding raises the question of whether physiological mechanisms underlying the acclimatization to high altitude identifies therapeutic targets for the effective treatment of severe acute respiratory syndrome pivotal to the reduction of global mortality during the COVID-19 pandemic. This article compares the symptoms of acute mountain sickness (AMS) with those of SARS-CoV-2 infection and explores overlapping patho-physiological mechanisms of the respiratory system including impaired oxygen transport, pulmonary gas exchange and brainstem circuits controlling respiration.

Does the pathogenesis of SARS-CoV-2 virus decrease at high-altitude?

In the present study we analyze the epidemiological data of COVID-19 of Tibet and high-altitude regions of Bolivia and Ecuador, and compare to lowland data, to test the hypothesis that high-altitude inhabitants (+2,500 m above sea-level) are less susceptible to develop severe adverse effects in acute SARS-CoV-2 virus infection. Analysis of available epidemiological data suggest that physiological acclimatization/adaptation that counterbalance the hypoxic environment in high-altitude may protect from severe impact of acute SARS-CoV-2 virus infection. Potential underlying mechanisms such as: (i) a compromised half-live of the virus caused by the high-altitude environment, and (ii) a hypoxia mediated down regulation of angiotensin-converting enzyme 2 (ACE2), which is the main binding target of SARS-CoV-2 virus in the pulmonary epithelium are discussed.

Do over 200 million healthy altitude residents really suffer from chronic Acid-base disorders?

As the oxygen tension of inspired air falls with increasing altitude in normal subjects, hyperventilation ensues. This acute respiratory alkalosis, induces increased renal excretion of bicarbonate, returning the pH back to normal, giving rise to compensated respiratory alkalosis or chronic hypocapnia. It seems a contradiction that so many normal people at high altitude should permanently live as chronic acid-base patients.

Lens autofluorescence is not increased at high altitude.

Purpose: To study the relation between ambient environmental ultraviolet radiation exposure and lens fluorescence.

Methods: Non-invasive lens fluorometry measurements were compared in healthy Bolivian and Danish subjects. Background ultraviolet radiation was 4.

Retinal vessel diameters in relation to hematocrit variation during acclimatization of highlanders to sea level altitude.

Purpose: To examine variations in retinal vessel diameters during acclimatization of native highlanders to normobaric normoxia at sea level.

Methods: Fifteen healthy residents of the greater La Paz region in Bolivia (3600 m above sea level) were examined thrice over a 72-day period, after having traveled by airplane to Copenhagen, Denmark, near sea level.

Results: In the study subjects, hematocrit decreased from 49.

The effect of high- to low-altitude adaptation on the multifocal electroretinogram.

Purpose: To examine variations in retinal electrophysiology assessed by multifocal electroretinogram (mfERG) during acclimatization of native highlanders to normobaric normoxia at sea level.

Methods: Eight healthy residents of the greater La Paz area in Bolivia (3600 m above sea level) were examined over 72 days after arriving in Copenhagen, Denmark (sea level). A control group of eight healthy lowlanders was used for comparison.

Decompression sickness following seawater hunting using underwater scooters.

Since the 1960s there have been several reports of divers suffering from decompression sickness (DCS) after repetitive breath-hold (BH) diving. In the period from 1995 to 2000 John Batle observed apparent DCS in 30 free divers competing with underwater scooters in the sea around Mallorca. The cases were treated successfully with recompression therapy.

High altitude diving depths.

In order to make any sea level dive table usable during high altitude diving, a new conversion factor is created. We introduce the standardized equivalent sea depth (SESD), which allows conversion of the actual lake diving depth (ALDD) to an equivalent sea dive depth. SESD is defined as the sea depth in meters or feet for a standardized sea dive, equivalent to a mountain lake dive at any altitude, such that [image omitted] [image omitted] [image omitted] Mountain lakes contain fresh water with a relative density that can be standardized to 1,000 kg m(-3), and sea water can likewise be standardized to a relative density of 1,033 kg m(-3), at the general gravity of 9.

Consensus statement on chronic and subacute high altitude diseases.

This is an international consensus statement of an ad hoc committee formed by the International Society for Mountain Medicine (ISMM) at the VI World Congress on Mountain Medicine and High Altitude Physiology (Xining, China; 2004) and represents the committee's interpretation of the current knowledge with regard to the most common chronic and subacute high altitude diseases. It has been developed by medical and scientific authorities from the committee experienced in the recognition and prevention of high altitude diseases and is based mainly on published, peer-reviewed articles. It is intended to include all legitimate criteria for choosing to use a specific method or procedure to diagnose or manage high altitude diseases.