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This is the first study to describe the daytime evolution of respiratory parameters in mechanically ventilated COVID-19 patients. The data base refers to patients hospitalised in the intensive care unit (ICU) at Arequipa Hospital (Peru, 2335 m) in 2021. In both survivors (S) and non-survivors (NS) patients, a remarkable decrease in respiratory compliance was observed, revealing a proportional decrease in inflatable alveolar units. The S and NS patients were all hyperventilated and their SatO2 was maintained at >90%. However, while S remained normocapnic, NS developed progressive hypercapnia. We compared the efficiency of O2 uptake and CO2 removal in the air blood barrier relying on a model allowing to partition between diffusion and perfusion limitations to gas exchange. The decrease in O2 uptake was interpreted as diffusion limitation, while the impairment in CO2 removal was modelled by progressive perfusion limitation. The latter correlated with the increase in positive end-expiratory pressure (PEEP) and plateau pressure (Pplat), leading to capillary compression, increased blood velocity, and considerable shortening of the air-blood contact time.
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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. Secondary aims were to assess the predictive factors for mortality, characteristics of mechanical ventilation setting, extubation rates, and analytical parameters. METHODS: This is a retrospective cohort study in critically ill patients with COVID-19 admitted to a hospital in Quito-Ecuador (2,850 m) from Apr 1, 2020, to Nov 1, 2021. Patients were cathegorized as normal weight, overweight, and obese, according to body mass index [BMI]). RESULTS: In the final analysis 340 patients were included, of whom 154 (45%) were obese, of these 35 (22.7%) were hypertensive and 25 (16.2%) were diabetic. Mortality in obese patients (31%) was lower than in the normal weight (48%) and overweight (40%) groups, but not statistically significant (p = 0.076). At multivariable analysis, in the overall population, older age (> 50 years) was independent risk factor for mortality (B = 0.93, Wald = 14.94, OR = 2.54 95%CI = 1.58-4.07, p < 0.001). Ferritin and the neutrophil/lymphocyte ratio were independent predictors of mortality in obese patients. Overweight and obese patients required more positive and-expiratory pressure compared to normal-weight patients. In obese patients, plateau pressure and mechanical power were significantly higher, whereas extubation failure was lower as compared to overweight and normal weight. CONCLUSIONS: This preliminary study suggests that BMI was not associated with mortality in critically ill patients at high altitude. Age was associated with an increase in mortality independent of the BMI. Biomarkers such as ferritin and neutrophils/lymphocytes ratio were independent predictors of mortality in obese patients with COVID-19 at high altitude.
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COVID-19 , Sobrepeso , Humanos , Sobrepeso/complicaciones , Estudios Retrospectivos , Enfermedad Crítica , Altitud , COVID-19/complicaciones , Obesidad/complicaciones , Índice de Masa Corporal , Biomarcadores , Unidades de Cuidados IntensivosRESUMEN
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. Epithelial and endothelial cell damage can result from the virus attack, thus leading to immune-mediated response. Pulmonary histopathological findings show the presence of Mallory bodies, alveolar coating cells with nuclear atypia, reactive pneumocytes, reparative fibrosis, intra-alveolar hemorrhage, moderate inflammatory infiltrates, micro-abscesses, microthrombus, hyaline membrane fragments, and emphysema-like lung areas. COVID-19 patients may present different respiratory stages from silent to critical hypoxemia, are associated with the degree of pulmonary parenchymal involvement, thus yielding alteration of ventilation and perfusion relationships. This review aims to: discuss the morphological (histopathological and radiological) and functional findings of COVID-19 compared to acute interstitial pneumonia, acute respiratory distress syndrome (ARDS), and high-altitude pulmonary edema (HAPE), four entities that share common clinical traits, but have peculiar pathophysiological features with potential implications to their clinical management.
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COVID-19 , Neumonía , Edema Pulmonar , Síndrome de Dificultad Respiratoria , Humanos , COVID-19/complicaciones , SARS-CoV-2 , Altitud , Edema Pulmonar/diagnóstico por imagen , Edema Pulmonar/etiologíaRESUMEN
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. Acute Mountain Sickness, High Altitude Pulmonary Edema, and High Altitude Cerebral Edema are medical conditions that some travelers can face. We present how to diagnose and treat acute high altitude pathologies, based on 51 years of high altitude physiology research and medical practice in hypobaric hypoxic diseases in La Paz, Bolivia (3,600 m; 11,811 ft), at the High Altitude Pulmonary and Pathology Institute (HAPPI - IPPA). These can occasionally present after flights to high altitude cities, both in lowlanders or high-altitude residents during re-entry. Acute high altitude ascent diseases can be adequately diagnosed and treated in high altitude cities following the presented guidelines. Treating these high-altitude illnesses, we had no loss of life. Traveling to a high altitude with sound medical advice should not be feared as it has many benefits. Nowadays, altitude descent and evacuation are not mandatory in populated highland cities, with adequate medical resources.
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Mal de Altura , Edema Encefálico , Edema Pulmonar , Humanos , Mal de Altura/diagnóstico , Mal de Altura/epidemiología , Mal de Altura/complicaciones , Altitud , Edema Encefálico/complicaciones , Edema Encefálico/terapia , Edema Pulmonar/complicaciones , Bolivia/epidemiología , Enfermedad AgudaRESUMEN
Purpose: To identify the frequency of anemia in pregnant women at different geographical altitudes in the Arequipa region of Peru. Methods: A quantitative, descriptive, and retrospective study was carried out. The study population consisted of 35,725 pregnant women living in the Arequipa Region at different altitudes. Data on age, gestational age, weight, height, province of residence, altitude, hemoglobin were collected. Results: Using World Health Organization altitude adjusted hemoglobin values, anemia prevalence in pregnant women between 2018-2019 was 13.7 percent in the Arequipa Region, while using unadjusted hemoglobin, the overall prevalence was 4.1 percent. When analyzed by altitudes, the frequency of anemia was 9.77 percent below 1 000 m 13.1 percent between 1 000-1 999 m, 13.1 percent between 2.000-2.999 m, 31.5 percent between 3.000-3.999 and 47.1 percent between 4.000-4.999. Nevertheless, when using unadjusted hemoglobin values rates were 6.67 percent for the 1.000-1.999 range, 2.39 percent for ranges between 2.000-2.999 m and 3.000-3.999 m, and 5.19 percent for altitudes above 4.000 m. Conclusions: There is a directly proportional correlation in the prevalence of anemia in pregnant women and higher altitude (p<0.01) as well as levels of anemia during the last trimester of pregnancy. Adjusting the hemoglobin values by altitude results in triple the prevalence of anemia. A throughout revision of the suitability of current guidelines to diagnose and prevent anemia at high altitude is recommended (AU)
Objetivo: Identificar la frecuencia de anemia en gestantes de diferentes altitudes geográficas en la región Arequipa, Perú. Métodos: Se realizó un estudio cuantitativo, descriptivo y retrospectivo. La población de estudio estuvo constituida por 35 725 gestantes residentes en la Región Arequipa a diferentes altitudes. Se recogieron datos de edad, edad gestacional, peso, talla, provincia de residencia, altitud, hemoglobina. Resultados: Utilizando los valores de hemoglobina ajustados por altitud de la Organización Mundial de la Salud, la prevalencia de anemia en gestantes entre 2018-2019 fue de 13,7 por ciento en la Región Arequipa, mientras que utilizando la hemoglobina no ajustada, la prevalencia global fue de 4,1 por ciento. Al analizar por altitudes, la frecuencia de anemia fue de 9,77 por ciento por debajo de 1 000 m 13,1 por ciento entre 1 000-1 999 m, 13,1 por ciento entre 2 000-2 999 m, 31,5 por ciento entre 3 000-3 999 y 47,1 por ciento entre 4 000-4 999. Sin embargo, cuando se utilizaron valores de hemoglobina no ajustados, las tasas fueron del 6,67 por ciento para el intervalo de 1 000-1 999, del 2,39 por ciento para los intervalos entre 2 000-2 999 m y 3 000-3 999 m, y del 5,19 por ciento para altitudes superiores a 4 000 m. Conclusiones: Existe una correlación directamente proporcional en la prevalencia de anemia en embarazadas y mayor altitud (p<0,01), así como niveles de anemia durante el último trimestre del embarazo. Ajustando los valores de hemoglobina por la altitud se triplica la prevalencia de anemia. Se recomienda una revisión en profundidad de la idoneidad de las directrices actuales para diagnosticar y prevenir la anemia a gran altitud(AU)
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Humanos , Embarazo , Niño , Adolescente , Adulto , Persona de Mediana Edad , Hemoglobinas/análisis , Mujeres Embarazadas/etnología , Anemia/epidemiología , Epidemiología Descriptiva , Estudios RetrospectivosRESUMEN
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. EXPERT OPINION: ARDS is defined as a syndrome rather than a distinct pathologic entity. There is great heterogeneity regarding the pathophysiologic, clinical, radiologic, and biological phenotypes in patients with ARDS, challenging clinicians, and scientists to discover new therapies. COVID-19 has been described as a cause of pulmonary ARDS and has reopened many questions regarding the pathophysiology of ARDS itself. COVID-19 lung injury involves direct viral epithelial cell damage and thrombotic and inflammatory reactions. There are some differences between ARDS and COVID-19 lung injury in aspects of aeration distribution, perfusion, and pulmonary vascular responses.
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COVID-19 , Lesión Pulmonar , Síndrome de Dificultad Respiratoria , Insuficiencia Respiratoria , COVID-19/complicaciones , Humanos , Pulmón/patología , Síndrome de Dificultad Respiratoria/terapia , SARS-CoV-2RESUMEN
Patients admitted to the Intensive Care Unit (ICU) with acute hypoxemic respiratory failure automatically receive oxygen therapy to improve inspiratory oxygen fraction (FiO2). Supplemental oxygen is the most prescribed drug for critically ill patients regardless of altitude of residence. In high altitude dwellers (i.e. in La Paz [≈3,400 m] and El Alto [≈4,150 m] in Bolivia), a peripheral oxygen saturation (SatpO2) of 89-95% and an arterial partial pressure of oxygen (PaO2) of 50-67 mmHg (lower as altitude rises), are considered normal values ââfor arterial blood. Consequently, it has been suggested that limiting oxygen therapy to maintain SatpO2 around normoxia may help avoid episodes of hypoxemia, hyperoxemia, intermittent hypoxemia, and ultimately, mortality. In this study, we evaluated the impact of oxygen therapy on the mortality of critically ill COVID-19 patients who permanently live at high altitudes. A multicenter cross-sectional descriptive observational study was performed on 100 patients admitted to the ICU at the "Clinica Los Andes" (in La Paz city) and "Agramont" and "Del Norte" Hospitals (in El Alto city). Our results show that: 1) as expected, fatal cases were detected only in patients who required intubation and connection to invasive mechanical ventilation as a last resort to overcome their life-threatening desaturation; 2) among intubated patients, prolonged periods in normoxia are associated with survival, prolonged periods in hypoxemia are associated with death, and time spent in hyperoxemia shows no association with survival or mortality; 3) the oxygenation limits required to effectively support the intubated patients' survival in the ICU are between 89% and 93%; 4) among intubated patients with similar periods of normoxemic oxygenation, those with better SOFA scores survive; and 5) a lower frequency of observable reoxygenation events is not associated with survival. In conclusion, our findings indicate that high-altitude patients entering an ICU at altitudes of 3,400 - 4,150 m should undergo oxygen therapy to maintain oxygenation levels between 89 and 93 %.
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COVID-19/fisiopatología , COVID-19/terapia , Cuidados Críticos/normas , Terapia por Inhalación de Oxígeno/normas , Saturación de Oxígeno/fisiología , Adulto , Anciano , Altitud , Bolivia , Cuidados Críticos/métodos , Enfermedad Crítica , Estudios Transversales , Femenino , Humanos , Masculino , Persona de Mediana Edad , Terapia por Inhalación de Oxígeno/métodosRESUMEN
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. High-Altitude Pulmonary Edema (HAPE) can be better understood through the Oxygen Transport Triad, which involves the pneumo-dynamic pump (ventilation), the hemo-dynamic pump (heart and circulation), and hemoglobin. The two pumps are the first physiologic response upon initial exposure to hypobaric hypoxia. Hemoglobin is the balancing energy-saving time-evolving equilibrating factor. The acid-base balance must be adequately interpreted using the high-altitude Van Slyke correction factors. Pulse-oximetry measurements during breath-holding at high altitude allow for the evaluation of high altitude diseases. The Tolerance to Hypoxia Formula shows that, paradoxically, the higher the altitude, the more tolerance to hypoxia. In order to survive, all organisms adapt physiologically and optimally to the high-altitude environment, and there cannot be any "loss of adaptation". A favorable evolution in HAPE and pulmonary hypertension can result from the oxygen treatment along with other measures.
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Mal de Altura , Hipertensión Pulmonar , Edema Pulmonar , Altitud , Humanos , Hipertensión Pulmonar/etiología , Hipoxia , Oxígeno , Edema Pulmonar/etiologíaRESUMEN
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. Given that EPO in the blood is increased at high-altitude, we evaluated the serum levels of EPO in critical patients with COVID-19 at "Hospital Agramont" in the city of El Alto (4150 masl) in Bolivia. A total of 16 patients, 15 men, one woman, with a mean age of 55.8 ± 8.49 years, admitted to the Intensive Care Unit were studied. All patients were permanent residents of El Alto, with no travel history below 3000 masl for at least one year. Blood samples were collected upon admission to the ICU. Serum EPO concentration was assessed using an ELISA kit, and a standard technique determined hemoglobin concentration. Only half of the observed patients survived the disease. Remarkably, fatal cases showed 2.5 times lower serum EPO than survivors (2.78 ± 0.8643 mU/mL vs 7.06 ± 2.713 mU/mL; p = 0.0096), and 1.24 times lower hemoglobin levels (13.96 ± 2.56 g/dL vs 17.41 ± 1.61 g/dL; p = 0.0159). While the number of cases evaluated in this work is low, our findings strongly warrant further investigation of EPO levels in COVID-19 patients at high and low altitudes. Our results also support the hypothesis that exogenous EPO administration could help critically ill COVID-19 patients overcome the disease.
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Altitud , COVID-19/sangre , Eritropoyetina/sangre , Pulmón/diagnóstico por imagen , Anciano , Bolivia , COVID-19/diagnóstico por imagen , COVID-19/mortalidad , Femenino , Hemoglobinas/metabolismo , Humanos , Unidades de Cuidados Intensivos , Masculino , Persona de Mediana Edad , Pronóstico , Factores de Riesgo , SARS-CoV-2 , Índice de Severidad de la Enfermedad , Tomografía Computarizada por Rayos XRESUMEN
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. Our results confirm our previous finding, further showing that the incidence of COVID-19 on the American continent decreases significantly starting at 1,000 m above sea level (masl). Moreover, epidemiological modeling indicates that the virus transmission rate is lower in the highlands (>1,000 masl) than in the lowlands (<1,000 masl). Finally, evaluating the differences in the recovery percentage of patients, the death-to-case ratio, and the theoretical fraction of undiagnosed cases, we found that the severity of COVID-19 is also decreased above 1,000 m. We conclude that the impact of the COVID-19 decreases significantly with altitude.
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Altitud , COVID-19/patología , COVID-19/epidemiología , COVID-19/transmisión , COVID-19/virología , América Central/epidemiología , Humanos , Incidencia , América del Norte/epidemiología , SARS-CoV-2/aislamiento & purificación , Índice de Severidad de la Enfermedad , América del Sur/epidemiologíaRESUMEN
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. METHODS: We present how to diagnose and treat acute high altitude pathologies (hypobaric hypoxic diseases) based on 50 years of experience in both: high altitude physiology research and medical practice as clinicians, in La Paz, Bolivia (3,600 m; 11,811 ft), at the High Altitude Pulmonary and Pathology Institute (HAPPI - IPPA). RESULTS: Acute Mountain Sickness, High Altitude Pulmonary Edema, and High Altitude Cerebral Edema are medical conditions faced by some travelers. These can occasionally present after flights to high altitude cities, both in lowlanders or in high altitude residents during re-entry, having spent more than 20 days at sea level. CONCLUSIONS: Traveling to high altitude should not be feared as it has many benefits; Acute high altitude ascent diseases can be adequately diagnosed and treated without descent.
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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. Initially, past-experience lead to the implementation of standardized protocols assuming this disease would be the same as SARS-CoV. Impulsive use of ventilators in extreme cases ended up in up to 88% fatality. We compare medical and physiological high altitude acute and chronic hypoxia experience with COVID-19 hypoxemia. A pathophysiological analysis is performed based on literature review and histopathological findings. Application of the Tolerance to Hypoxia formula = Hemoglobin/PaCO2 + 3.01 to COVID-19, enlightens its critical hypoxemia. Pneumolysis is defined as progressive alveolar-capillary destruction resulting from the CoV-2 attack to pneumocytes. The adequate interpretation of the histopathological lung biopsy photomicrographs reveals these alterations. The three theoretical pathophysiological stages of progressive hypoxemia (silent hypoxemia, gasping, and death zone) are described. At high altitude, normal low oxygen saturation (SpO2) levels (with intact lung tissue and adequate acid-base status) could be considered silent hypoxemia. At sea level, in COVID-19, the silent hypoxemia starting at SpO2 ≤ 90% (comparable to a normal SPO2 {88-92%} at 3500 m) suddenly evolves to critical hypoxemia. This, as a consequence of progressive pneumolysis + inflammation + overexpressed immunity + HAPE-type edema resulting in pulmonary shunting. The proposed treatment is based on the improvement of the Tolerance to Hypoxia (Hemoglobin factor), oxygen therapy, inflammation reduction, antibiotics, antitussives, rehydration & anticoagulation if required. Understanding the pathophysiology of COVID-19 may assist in this disease's management.
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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. However, up to 88% of the patients on ventilators lost their lives. It was suggested that COVID-19 could be similar to a High-Altitude Pulmonary Edema (HAPE). New observations and pathological findings are gradually clarifying the disease. METHODS: As high-altitude medicine and hypoxia physiology specialists working and living in the highlands for over 50 years, we perform a perspective analysis of hypoxic diseases treated at high altitudes and compare them to Covid-19. Oxygen transport physiology, SARS-Cov-2 characteristics, and its transmission, lung imaging in COVID-19, and HAPE, as well as the causes of clinical signs and symptoms, are discussed. RESULTS: High-altitude oxygen transport physiology has been systematically ignored. COVID-19 signs and symptoms indicate a progressive and irreversible failure in the oxygen transport system, secondary to pneumolysis produced by SARS-Cov-2's alveolar-capillary membrane "attack". HAPE's pulmonary compromise is treatable and reversible. COVID-19 is associated with several diseases, with different individual outcomes, in different countries, and at different altitudes. CONCLUSIONS: The pathophysiology of High-altitude illnesses can help explain COVID-19 pathophysiology, severity, and management. Early diagnosis and use of EPO, acetylsalicylic-acid, and other anti-inflammatories, oxygen therapy, antitussives, antibiotics, and the use of Earth open-circuit- astronaut-resembling suits to return to daily activities, should all be considered. Ventilator use can be counterproductive. Immunity development is the only feasible long-term survival tool.
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COVID-19/metabolismo , COVID-19/fisiopatología , Oxígeno/metabolismo , Mal de Altura/diagnóstico , Mal de Altura/metabolismo , Mal de Altura/fisiopatología , COVID-19/diagnóstico , COVID-19/terapia , Diagnóstico Diferencial , Humanos , Hipertensión Pulmonar/diagnóstico , Hipertensión Pulmonar/metabolismo , Hipertensión Pulmonar/fisiopatología , Ventiladores MecánicosRESUMEN
A very recent epidemiological study provides preliminary evidence that living in habitats located at 2500â¯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. In this context, we also discuss the potential impact of SARS-CoV-2 infection on oxygen sensing in the carotid body. Finally, since erythropoietin (EPO) is an effective prophylactic treatment for AMS, this article reviews the potential benefits of implementing FDA-approved erythropoietin-based (EPO) drug therapies to counteract a variety of acute respiratory and non-respiratory (e.g. excessive inflammation of vascular beds) symptoms of SARS-CoV-2 infection.
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Aclimatación/fisiología , Mal de Altura/fisiopatología , Infecciones por Coronavirus/tratamiento farmacológico , Infecciones por Coronavirus/fisiopatología , Eritropoyetina/farmacología , Hipoxia/fisiopatología , Neumonía Viral/tratamiento farmacológico , Neumonía Viral/fisiopatología , COVID-19 , Infecciones por Coronavirus/inmunología , Infecciones por Coronavirus/metabolismo , Humanos , Pandemias , Neumonía Viral/inmunología , Neumonía Viral/metabolismoRESUMEN
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.
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Betacoronavirus/fisiología , Infecciones por Coronavirus/epidemiología , Infecciones por Coronavirus/virología , Neumonía Viral/epidemiología , Neumonía Viral/virología , Altitud , Betacoronavirus/patogenicidad , Bolivia/epidemiología , COVID-19 , Susceptibilidad a Enfermedades , Ecuador/epidemiología , Humanos , Oxígeno , Pandemias , SARS-CoV-2 , Tibet/epidemiología , VirulenciaRESUMEN
After the accident on Apolo1, with 100% oxygen in the cabin, all spaceships now travel with a sea level pressure and 20.9% oxygen. Extravehicular activity requires lowering the pressures. It is complex and time consuming. Permanently reducing the cabin pressure would be a great advantage. A paper by NASA in 2013, proposed for the spaceflight environment: 8 psia / 32% O2 (reducing the sea level pressure (14.7 psi / 20.9% O2), but increasing the fraction of oxygen in order to replicate the sea level PaO2). However, we question this proposal, as it is based on the fear of hypoxia. Our proposal back in 2007 suggested that space travel should take place in a hypobaric environment of 9.5 psi / 20.9% O2 (like in the city of La Paz-Bolivia (3,600m) [11,811ft]). The logic behind it is that at all altitudes on planet Earth, life thrives in a 20.9% Oxygen, 79% Nitrogen. PaCO2 also needs to be considered. In a physiological manner, over 200 million inhabitants of high altitude above 2,000m [6,561ft], have perfectly normal lives. The astronauts could benefit of a Extra-Vehicular Activity (EVA) suit pressure of only 149 mmHg [2.8psi] (lighter, much more comfortable and efficient spacesuits) and space travel anemia could be reduced. The preparation prior-to-space travel could be carried out by adapting and living in a high altitude environment. We consider chronic hypoxia a fundamental step in BioSpaceForming (Adaptation to life in space). As all living beings start to move out of Earth into space, they will have to change their biology and adapt to new conditions.
Después del accidente del Apolo 1, ocurrido con 100 % de oxígeno en la cabina, todas las naves espaciales viajan con una presión de nivel del mar y 20,9 % de oxígeno. La actividad extravehicular requiere que se reduzcan las presiones. Es un proceso complejo que consume mucho tiempo. Reducir la presión de la cabina de manera permanente sería una gran ventaja. En un artículo de la NASA de 2013 se proponen las siguientes condiciones para el entorno de los vuelos espaciales: 8 psia / 32 % O2 (reduciendo la presión de nivel del mar (14,7 psi / 20,9 % O2), pero incrementando la fracción de oxígeno para replicar la PaO2 de nivel del mar). Sin embargo, nosotros nos cuestionamos esa propuesta, ya que está basada en el miedo a la hipoxia. La propuesta que hicimos en 2007 sugería que los vuelos espaciales se realizaran en un entorno hipobárico de 9,5 psi / 20,9 % O2 (como en la ciudad de La Paz, Bolivia (3 600 m) [11 811 ft]). El fundamento lógico es que en el planeta Tierra la vida se desarrolla a todas las alturas con 20,9 % oxígeno, 79 % nitrógeno, aunque también hay que tener en cuenta la PaCO2. Desde el punto de vista fisiológico, más de 200 millones de habitantes de grandes alturas de más de 2 000 m [6 561 ft] tienen una vida perfectamente normal. Para la Actividad Extra-Vehicular (EVA) a los astronautas les convendría más que el traje tuviera una presión de sólo 149 mmHg [2,8 psi], es decir, un traje más ligero y mucho más cómodo y eficiente, a la vez que se reduciría la ocurrencia de anemia espacial. La preparación previa al vuelo espacial podría basarse en la adaptación a un entorno de gran altitud y la vida en el mismo. Consideramos que la hipoxia crónica es un paso fundamental en la adaptación biológica y la supervivencia en el espacio. Todo organismo vivo que se traslade de la Tierra al espacio debe cambiar su biología y adaptarse a las nuevas condiciones.