View clinical trials related to High Altitude.
Filter by:It was reported that up to 76% people who rapidly ascend to the altitude higher than 4500 m without sufficient acclimatization will have AMS which often develops 6-8 hours after reaching at high altitude. AMS could be improved if there is no continuous ascent although central sleep apnea may persist much longer. It has also been well documented that exercise capacity was impaired at high altitude. Oxygen inhalation is the most effective treatment method, but it is impractical for outdoor activities because of the large volume required. There are some drugs such as acetazolamide, and ibuprofen for relieving AMS but side effects and inconsistent treatment effect made them to be difficulty for routine use. It is noted that adding CO2 might be useful for improvement of hypoxia and exercise ability and eliminating CSA. There is no available device which can accurately supply constant CO2 and is functionally free of dead space. We innovated a portable device with a special mask for supplement of CO2 for prophylaxis and treatment of AMS.
To understand alterations in glycogen and molecular regulation of skeletal muscle glucose uptake, glycogen synthesis, and muscle protein recovery when consuming CHO (glucose) or CHO+PRO (glucose + whey) post-exercise during unacclimatized high altitude exposure, randomized crossover double blinded studies will be conducted in the hypobaric/hypoxic chamber at USARIEM Table 1. Briefly, the study consists of a 2 day baseline period at SL followed by two, 3 day trial periods (with the 3rd day being a testing day) at HA. The baseline is separated from trial 1 for a least a day, and trial 1 & 2 separated by at least 4 days. Volunteers will consume CHO (glucose) or CHO+PRO (glucose + whey) drinks post-exercise during unacclimatized high altitude exposure during the two trial periods. The order of the drinks will be randomized (using a random number generator such as randomizer.org) and kept by a study staff not directly involved in data collection to maintain blinding.
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 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 membrane lung oxygen uptake 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.