View clinical trials related to Altitude Hypoxia.
Filter by:Dyspnea and exercise intolerance are well known to travelers who have experienced time at high elevations, greater than 2500 meters (8200 feet). As individuals ascend to higher elevations, oxygen saturations significantly decrease as the partial pressure of oxygen decreases. Additionally, many individuals develop subclinical cases of high altitude pulmonary edema (HAPE), which may worsen hypoxemia and decrease exercise performance. While dyspnea and exercise intolerance are usually self-limiting and improve with rest, some individuals experience severe symptoms that prevent safe evacuation to lower elevation. Individuals experiencing high altitude dyspnea, subclinical HAPE, or clinical HAPE will see improvements in symptoms and SpO2 when receiving supplemental oxygen, however this requires heavy and unwieldy tanks that make it difficult to carry across irregular terrain. Additionally, given the often-remote conditions where supplemental oxygen is needed, it is often difficult to replenish supplies. Other devices, such as the portable hyperbaric chamber (often referred to as Gamow bag), can temporarily improve dyspnea and oxygen saturation at high and extreme altitudes without the use of oxygen tanks. This device also carries some of the same disadvantages as supplemental oxygen, however, as the bag is also heavy and patients are not ambulatory while using the device. Similar to supplemental oxygen and the portable hyperbaric chamber, there is some evidence that CPAP may improve SpO2 and dyspnea at high and extreme altitudes. CPAP has already demonstrated significant efficacy in reducing symptoms of acute mountain sickness (AMS) when used in the field. At the time these small studies were conducted, CPAP therapy carried similar disadvantages in weight and portability. In recent years, however, CPAP devices have become increasingly lightweight and portable, with recent models weighing less than 1 kilogram (2.2 pounds). These devices are often powered by batteries, which themselves are light and easy to carry, and can be charged in the field using either a generator or foldable solar panels. These newer features of CPAP devices overcome some of the previous disadvantages that have limited its potential uses. CPAP devices can easily be carried across difficult terrain directly to individuals suffering from altitude-related symptoms, to be used as a rescue device until definitive care is available. Its portability not only allows for easy delivery to a patient, but also may allow for a patient to experience enough symptom relief to walk themselves down to lower elevation, greatly improving speed and resource utilization involved in high altitude rescues. In previous studies, CPAP devices have been found to be effective and safe to use in high and extreme altitude locations. While a few pilot studies have assessed CPAP's utility in treating dyspnea and SpO2 at altitude, these studies were done at rest. While one study showed improved symptoms and SpO2 in normobaric and hypobaric hypoxia, the study was limited by its lack of real-world condition, and its authors suggested further study in field and extreme environmental conditions. Additional investigation is needed to determine whether or not CPAP is an effective tool in the field to improve SpO2, dyspnea, and exercise tolerance in individuals traveling at high elevations.
In this study, the objective is to compare neonatal cerebral oxygenation and electrical activity within 3 days after birth across different altitude areas using non-invasive methods, specifically near infrared spectroscopy (NIRS) and amplitude-integrated electroencephalography (aEEG), and establish reference value for each altitude level.
• The purpose of this study is to investigate which physiological process that controls normal human body homeostasis is affected by low levels of acute hypoxic exposure and whether there is a difference in those physiological processes and simulated flight performance between a rapid and ramp hypoxic exposure. To accomplish this, pilot analogs will be exposed to normoxic, simulated 8,000 ft (2438 m), simulated 12,000 ft (3658 m), and a ramp exposure breathing at simulated 8,000 ft for 5 minutes before ascending to simulated 12,000 ft while flying in a flight simulator. During the flight simulator, participants will need to accomplish three tasks: 1) Maintaining an altitude of 5,000 ft of elevation while performing a mental math test, 2) Flying the aircraft through the center of a series of 7 targets, and 3) Taking off and flying the aircraft a short distance to land on the center of an indicated target. Physiological measures of heart rate variability (HRV), blood pressure (BP), peripheral oxygen saturation (SpO2), electrodermal activity (EDA), and neck neuromuscular activity using electromyography (EMG) will be measured for this study. Along with questionnaires to assess hypoxic symptoms, simulator sickness, and self-perceived workload for each task
A ketogenic diet (KD) reduces daily carbohydrates (CHOs) ingestion by replacing most calories with fat. KD is of increasing interest among athletes because it may increase their maximal oxygen uptake (VO2max), the principal performance limitation at high altitudes. The investigators examined the tolerance of a 4-week isocaloric KD (ICKD) under simulated hypoxia and the possibility of evaluating ICKD performance benefits with a maximal graded exercise bike test under hypoxia and collected data on the effect of the diet on performance markers and arterial blood gases.
The aim of this study is to investigate the effect of pre-acclimatization in a nitrogen tent at home, ventilated with a slightly increased nitrogen percentage, in preparation for an expedition at extreme altitude. Specifically, the current study aims to gather knowledge, whether pre-acclimatization, first, leads to improved capillary function during an expedition to extreme altitude, and second, affects incidence of altitude sickness and the likelihood of reaching the expedition destination without oxygen supplementation. The project will be carried out in two phases corresponding to two randomized controlled trials in healthy volunteers, who are participating in an expedition at extreme altitudes with or without pre-acclimatization.
One of the most common nutritional deficiencies worldwide is iron deficiency. Iron deficiency is considered the main cause of anaemia in developing countries, including those in South America. The most recent surveys report that the prevalence of anaemia is as high as, 40 and 25% in Peru. Populations living at higher altitudes may have higher iron requirements, as body iron is naturally increased in long-term high-altitude residents to compensate for the lower oxygen in the air at high altitudes. However, the effects of chronic exposure to high altitude on iron status, body iron compartments and dietary iron requirements are incompletely understood. The primary objective of the proposed research is to determine iron bioavailability of iron from biofortified potatoes at different altitudes in populations of Andean descent. Human trials will be undertaken with volunteers in the Huancavelica region of Peru (elevation: 3676 meters) as well as in Lima (elevation close to sea level). The aim is to assess the effect of altitude on the absorption from a promising iron biofortified potato cultivar. These trials require incorporation of iron stable isotopes into the meals of the bio fortified potato and the analysis of the isotopes in subsequent blood (red blood cells) samples. Stable iron istotopes are considered the golden standard to assess human iron absorption and can be safely used as tracer substances in humans. The objective of the study is to compare, in volunteer females of childbearing age, the bioavailability of iron from bio-fortified potatoes in two locations of different altitudes and quantify the effect of altitude on iron bioavailability from a potato meal consumed over 5 consecutive days.
Pulse oximetry offers real time and non-invasive estimation of arterial oxygen saturation in a cost-effective way, and has become a critical tool in guiding the usage of supplemental oxygen in sick newborns. During postnatal transition, pulmonary pressure decreases upon the activation of the lungs, and the ductus arteriosus constricts and closes upon the increase of partial oxygen pressure, which is negatively correlated with altitude. As a result, postnatal transition may be different at high altitudes. Umbilical cord blood gas analysis is now recommended in all high-risk deliveries because of its' value in providing information about preceding fetal hypoxic stress. But there are only limited studies about the SpO2 measurements during the first few hours after birth and umbilical blood gas analysis at high altitudes, especially at altitudes above 2500m. The primary outcome of the study is to determine the reference intervals for preductal oxygen saturation during first 2 hours of life stratified by different gestational age. The secondary outcomes is to establish the pH and lactate cutoff value of umbilical arterial blood gas at different altitude level.
The purpose of this randomized, placebo-controlled double-blind trial is to evaluate efficacy of acetazolamide in preventing overt altitude-related adverse health effects (ARAHE) in lowlanders with chronic obstructive pulmonary disease (COPD) developing early signs of altitude-illness during altitude travel.
High blood pressure (BP) is one of the principal cardiovascular risk factors. While BP levels and hypertension prevalence are well characterized in many populations, information on BP and on cardiovascular risk profile in high altitude inhabitants is limited and frequently contradictory, especially in the large highland populations of South America. The information on the effects of permanent high altitude exposure on cardiovascular variables including BP may be relevant in the light of the known BP-increasing effect of acute exposure to high altitude hypoxia. This information may have practical implications for millions of people living at elevated altitudes in Asia, South America and Africa. The inconclusive epidemiological evidence on BP and cardiovascular risk in high altitude dwellers may be the result of several factors, among them: 1) confounding by genetic and socio-economic factors; 2) imperfect methods of BP evaluation, in particular lack of data on ambulatory and home BP (both methods considered superior to conventional clinic BP in the assessment of exposure to high BP). On this background, the general aim of the study is to compare blood pressure levels and cardiovascular risk profile among population-based samples of subjects residing in Peruvian communities living at different altitudes.
The aim of this study is to compare the psychophysiological effects of terrestrial altitude with a normobaric, hypoxic situation.