View clinical trials related to High Altitude.
Filter by:Apparent hypoxia-induced insulin insensitivity along with alterations in glucose kinetics suggests reduction in glucose uptake by the peripheral tissue is a primary factor contributing to reductions in exogenous glucose oxidation at HA. As such, the primary objective of this study is to determine the ability of an insulin sensitizer (Pioglitazone, PIO) to enhance exogenous glucose oxidation and metabolic clearance rate during metabolically-matched, steady-state exercise during acute HA exposure compared to placebo (PLA) in native lowlanders. Secondary objective of this study will be to assess the impact of PIO on markers of inflammation and iron status compared to PLA. This randomized crossover placebo control double blinded study will examine substrate oxidation and glucose kinetic responses to ingesting supplemental carbohydrate (glucose) during metabolically-matched, steady-state exercise with acute (~5 h) exposure to HA (460 mmHg, or 4300m, barometric pressure similar to Pike's Peak) after receiving PIO (HA+PIO), or after receiving a matched placebo (HA+PLA). Eight healthy, recreationally active males between the ages of 18-39 yrs will be required to complete this study. Following a 4 day glycogen normalization period receiving PIO or PLA daily, volunteers will complete two 80-min trials, performing metabolically-matched, steady-state aerobic (same absolute workload corresponding to ~55 ± 5% of V̇O2peak at HA) exercise on a treadmill, and consuming 145 g of glucose (1.8 g/min); one trial with HA+PIO and the other with HA+PLA. A dual glucose tracer (13C-glucose oral ingestion and [6,6-2H2]-glucose primed, continuous infusion) technique and indirect calorimetry will be used to selectively analyze endogenous and exogenous glucose oxidation, as well as glucose rate of appearance (Ra), disappearance (Rd) and metabolic clearance rate (MCR). Serial blood samples will be collected during each trial to assess endocrine and circulating substrate responses to exercise, carbohydrate, and hypoxia with or without PIO. All trials will occur at the same time of day in the USARIEM hypobaric/hypoxic chamber and be separated by a minimum 10-d washout period. The primary risks associated with this study include those associated with acute hypobaric hypoxia, exercise, and blood sampling.
Over the last 20 years, extracorporeal membrane oxygenation (ECMO) has been used to support adult patients with respiratory or cardiac failure who are unlikely to survive conventional treatment methods. ECMO circuit, pump, and oxygenator technology improvements permit safer perfusion for extended periods. The prolonged use of an ECMO circuit increases the risk of membrane lung (ML) dysfunction. The ML is responsible for taking in oxygen and removing carbon dioxide. The non-biologic surface of the ML triggers inflammatory and coagulation pathways, resulting in the formation of blood clots, breakdown of fibrin, and activation of white blood cells, which ultimately leads to ML dysfunction. Coagulation and fibrinolysis activation can cause systemic coagulopathy or hemolysis, and the deposition of blood clots can block blood flow. Moreover, the accumulation of moisture in the gas phase and the buildup of protein and cellular debris in the blood phase may contribute to shunt and dead-space physiology, respectively, impairing the exchange of gases. These three categories-hematologic abnormalities, mechanical obstruction, and inadequate gas exchange-account for most ML exchanges. Worsening oxygenation during ECMO should prompt quantification of oxygen transfer. ML exchange is indicated when the ML can no longer meet the patient's oxygen demand. The partial pressure of Post-ML arterial oxygen less than 200 mmHg is the most important consideration in making this decision. In some high-altitude regions of China, ECMO treatment is also routinely conducted. The experiences above are derived from low-altitude areas, and whether they apply in high-altitude regions is still being determined. This study aimed to explore the significantly lower post-membrane oxygen partial pressure in high-altitude regions compared to low-altitude areas.
Human milk oligosaccharides (HMOs) are the third-most abundant component in mothers' milk and are an important prebiotic factor for the development of the gut microbiota of infants, promoting the growth of certain beneficial bacterial strains and providing protection against many bacterial and viral infections. HMOs induce immunomodulatory activity by affecting immune cell populations and functions. In a simulator of the adult human intestinal microbial ecosystem, fermentation of HMOs led to an increase of bifidobacteria in parallel with an increase in short-chain fatty acids as well as a reduction in inflammation markers, supporting the potential of HMOs to provide health benefits also in adults. Long-term stay in microgravity induces many physiological responses, including diminished immune function and impaired glucose tolerance which may lead to rather severe consequences. Similarly, hypoxia conditions as in the Concordia station, affects the immune system and may lead to impaired glucose tolerance and insulin resistance. The hypothesis is that HMOs as a prebiotic supplement will mitigate changes in immune function, glucose tolerance, lipid homeostasis, and neurotransmitter production. It is expected that HMO supplementation will - Modulate gut microbiota composition and function - Improve inflammation status - Improve immune function - Improve glucose tolerance - Improve nutritional status - Prevent changes in neurotransmitters associated with anxiety and depression. During the stay in Antarctica an HMO blend will be supplemented to the verum group of volunteers. The control group will receive a placebo. Experiment days with blood drawing, an oral glucose tolerance test, saliva sampling, and feces samples are planned once before, about every second month in Concordia, and once after return.
High altitude (>2400 m) is associated with decreased atmosphere pressure leading to hypoxia which in turn impairs exercise capacity and causes acute mountain sickness (AMS). It is noted that adding CO2 might be beneficial to improve hypoxia and exercise performance at high altitude. However, no device is currently available that can supply a constant low dose of CO2 during free movement at high altitude. We have recently invented a portable device which is small and light enough for supplement of low dose CO2 during field exercise at high altitude.
The aim of the researchers in this prospective study is to determine the differences, if any, in terms of anesthetic parameters among pregnant women who live at different altitudes and undergo cesarean section under neuraxial anesthesia under elective conditions and to contribute to the literature.
This study aims to compare the effect of the use of supraglottic jet oxygenation and ventilation (SJOV) with high-flow nasal oxygen therapy (HFNO) on reducing the rate of hypoxia during gastrointestinal endoscopic procedures in deeply sedated patients at high altitudes.
This study aims to determine whether the use of SOJV could reduce the rate of hypoxia during gastrointestinal endoscopic procedures in deeply sedated patients sedated at high altitude comparing to the supplemental oxygen administration via nasal cannula.
The now widely used reference interval for pulse oxygen saturation of the neonate after 24 hours of birth has been developed relying on data from low altitude.It is not suitable for neonates at high altitude. At present, no reference interval has been established at high altitude, and the existing studies have many limitations. So this study was designed.
This is a prospective, multicenter, cohort study aiming to explore the cardiotoxicity of targeted therapy for HER-2 positive breast cancer patients who lives in high altitude area. One hundred and thirty two HER-2 positive breast cancer patients who will receive neoadjuvant, adjuvant, or palliative targeted therapy will be enrolled. The cardiotoxicity of targeted therapy will be observed and recorded during the treatment and one year after the end of treatment. The subjects will be stratified by age, baseline cardiac risk factors, and anthracyclines.
The predictive value of the hypoxia altitude simulation test (HAST) or other baseline values to predict altitude-related adverse health effects (ARAHE) is not established. To address this gap, the main goals of this investigation will be 1) to evaluate the diagnostic accuracy of the HAST in identifying individuals that will experience ARAHE during altitude travel and 2) to establish prediction models incorporating other commonly assessed clinical characteristics either alone or in combination with the HAST as predictors of ARAHE in altitude travelers. Hypotheses: In lowlanders with COPD, a PaO2 <6.6 kPa or another cutoff of PaO2 or SpO2 at the end of the HAST, at rest or during exertion and/or clinical variables including symptoms, pulmonary function indices, 6-min walk distance (6MWD), either alone or combined to a multivariable model, will predict ARAHE during a sojourn of 2 days at 3100m with accuracy greater than chance