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

Pediatric high-altitude pulmonary edema and acute mountain sickness: Clinical features and risk determinants

OBJECTIVE

This investigation aimed to delineate the clinical manifestations associated with high-altitude pulmonary edema (HAPE) and acute mountain sickness (AMS) in pediatric populations and find the risk factors of HAPE.

METHODS

We conducted a retrospective analysis of clinical data from children under 18 years diagnosed with HAPE and AMS at an average altitude of 3000 m. The clinical data between these two groups were compared.

RESULTS

The study encompassed 74 pediatric patients, 27 with AMS and 47 with HAPE. HAPE presentations included classic HAPE (55.3%), reentry HAPE (27.7%), and high-altitude resident pulmonary edema (HARPE, 17.0%). Notably, 87.2% of HAPE cases were male, and 68.1% had a high body mass index (BMI). HARPE instances followed viral infections, prominently SARS-CoV-2. HAPE cases exhibited higher BMI, respiratory tract infections within 1 week preceding symptom onset, an increase in white blood cell counts (WBCs), lower peripheral arterial oxygen saturation (SpO2), and higher heart rate compared to the AMS group. Multivariate logistic regression pinpointed high BMI as an independent HAPE risk factor (odds ratio = 19.389, 95% confidence interval: 1.069-351.759, p = .045).

CONCLUSION

HAPE occurs predominantly in males, with high BMI identified as a critical independent risk factor. The study underscores the need for heightened awareness and preventive strategies against HAPE in children at high altitudes.

Recent Progress in the Understanding and Management of Acute Mountain Sickness: A Narrative Review

BACKGROUND

Individuals at higher altitudes may experience a decrease in blood oxygen levels, which can result in a variety of clinical illnesses, such as high-altitude pulmonary edema, high-altitude cerebral edema, and milder but more common acute mountain sickness (AMS).

OBJECTIVE

This study aims to review the current state of knowledge related to motion sickness, the risk of AMS, and pharmacological and non-pharmacological treatments for AMS.

METHODS

Several databases, including PubMed, Bentham Science, Elsevier, Springer, and Research Gate, were used to compile the data for the article following a thorough analysis of the various research findings connected to acute mountain sickness and motion sickness, along with treatments and prevention.

RESULTS

This article covers the research on mountain sickness as well as every imaginable form of conventional and alternative medicine. It contains ten medicinal plants that are useful in treating mountain sickness and various other remedies. Additionally, case studies are provided.

CONCLUSION

Therefore, the information in the paper will help travel medicine specialists better personalize their appropriate care for patients who travel to high-altitude locations. Additionally, all available antiemetic medications, serotonin agonists, nonsteroidal anti-inflammatory drugs, and herbal treatments for motion sickness were discussed. The prevention and consequences of acute mountain sickness are also covered in this study.

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 (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 ​​for 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 %.

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. 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.

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. 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.