Active clinical trials for "Altitude Sickness"

Prospective interventional trial in lowlanders evaluating effect of acute exposure, acclimatization and re-exposure to high altitude

Prospective interventional trial in lowlanders evaluating effect of acute exposure, acclimatization and re-exposure to high altitude.

The primary objective of the study is to investigate the effect of inhaled budesonide on the incidence of AMS. The primary study question to ask is: 1. Does inhaled budesonide reduce the incidence of AMS after rapid and active ascent to 4559 m? In addition, the secondary study questions to ask are: Does inhaled budesonide reduce the severity of AMS after rapid and active ascent to 4559 m? Are the effects of inhaled budesonide on AMS incidence and severity related to its plasma concentration? Study medication Inhaled budesonide at 2 different concentrations (2 x 200 µg, 2 x 800 µg) versus placebo Study design Prospective, controlled, single-center study on 51 healthy volunteers at 4559 m [Capanna Regina Margherita (Margherita Hut), Italy] With regard to the intervention (inhaled budesonide) double-blinded and randomized

Acute mountain sickness (AMS) is a syndrome of nonspecific symptoms and is therefore subjective. The Lake Louise Consensus Group defined acute mountain sickness as the presence of headache in an unacclimatized person who has recently arrived at an altitude above 2,500 m plus the presence of one or more of the following: gastrointestinal symptoms (anorexia, nausea, or vomiting), insomnia, dizziness, and lassitude or fatigue. An increase in RBC mass is a natural feature of altitude acclimatization. Hypoxia-induced erythropoietin (EPO) secretion begins hours after ascent and stimulates bone marrow production of red blood cells, but this takes weeks to effect an increase in red cell mass . Therefore, it is feasible that EPO therapy weeks before altitude exposure decrease high altitude illness. In 1996, Young et al in U.S. Army Research Institute of Environmental Medicine (USARIEM) reported that autologous erythrocyte infusion did not ameliorate the decrement in maximal oxygen uptake at 4,300m altitude despite increasing arterial oxygen carrying capacity. On the basis of this report, USARIEM did not recommend use of recombinant EPO for altitude acclimatization. However, increases in erythrocyte count, hematocrit and hemoglobin associated with EPO therapy have been shown to decrease fatigue and increase work capacity and exercise tolerance. In addition, improvement in CNS function and cognitive ability has been noted with EPO therapy. Subjective benefits include improvement in sleep habits, tolerance to cold; decreased dyspnea, anginal symptoms and tachycardia and improved appetite, all of which are symptoms associated with high altitude illness. The investigators also reported improved muscle energy metabolism with EPO in dialysis patients, but not with RBC transfusion. In this study, the investigators will conduct a randomised controlled trial to assess the effect of EPO administration on AMS at an altitude of 4,130 m.

The purpose of this study is to determine whether regular oral use of sildenafil citrate can prevent or attenuate high altitude illnesses.

The purpose of this research is to support a hypothesis that osteopathic manual medicine (OMM) and / or a 10 cmH2O end-expiratory pressure (PEEP) could be used in the prevention of acute mountain sickness (AMS). During altitude exposure, an exaggerated hypoxemia and the increase of intracranial pressure are both known to be major physipathological ways of AMS development. The goal of the osteopathic protocol is to release tension on the circulatory structures directly related to cranial circulation and drainage. The main hypothesis is that it could lead to lower intracranial pressure and help reducing AMS signs. Furthermore the investigators would like to define a osteopathic score for individual AMS sensitivity, based on cranial bones mobility. Several studies have shown that using PEEP at altitude (or hypoxia) increases SpO2. As for osteopathy protocol, the investigators would like to apply this experimental condition during real altitude exposure in a randomized controlled protocol.

Low oxygen at altitude causes pauses in breathing during sleep, called central sleep apnea. Central sleep apnea causes repeated awakenings and poor sleep. Low oxygen itself and the induced oxidative stress can damage mental function which is likely worsened by poor sleep. Reduced mental function due to low oxygen can pose a serious danger to mountain climbers. However there is also mounting evidence that even in populations of people that live at high altitudes and are considered adapted, low oxygen contributes to reductions in learning and memory. Therefore there is a serious need for treatments which may improve sleep, control of breathing and mental function during low oxygen. Melatonin is a hormone produced in the brain during the night which regulates sleep patterns with strong antioxidant and anti-inflammatory properties. A study previously reported that melatonin taken 90 mins before bed at 4,300 m (14,200 ft) induced sleep earlier, reduced awakenings and improved mental performance the following day. However how melatonin caused these effects was not determined. Therefore this study aims to determine how melatonin effects control of breathing, sleep and mental performance during exposure to low oxygen.

This study involved human volunteers undertaking a high-altitude expedition. It assessed changes in physiological parameters of relevance to high-altitude cardiopulmonary physiology. Participants included a subgroup of those taking part in an existing adventurous training expedition and were randomised in a 1:1 fashion to receive either intravenous iron or normal saline several weeks prior to departure. During the expedition, participants were investigated by means of transthoracic echocardiography, peripheral oxygen saturation measurement and heart rate monitoring and through the drawing of venous blood samples. Bloods were later analysed for markers of iron status.

This safety study is the first in a series of studies testing the application of the combination of aminophylline and methazolamide.

Commercial aircraft passengers are exposed to atmospheric pressures ranging from the pressure found at ground level to that encountered in the external environment at 8,000 feet. There is some evidence in the medical literature that symptoms of acute mountain sickness can result from ascent to altitudes of 6,300 to 10,000 feet by unacclimated persons during the first few days following ascent, probably due to the hypoxia that results from breathing air at the reduced ambient pressures at altitude. The logical hypothesis that follows is that exposure to 8,000 feet could cause hypoxia sufficient to adversely affect the comfort and well being of some commercial aircraft passengers on prolonged flights. There is insufficient data in the literature to validate this hypothesis. Exercise at sea level and at altitude reduces arterial oxygen levels. The logical hypothesis that follows is that the combination of moderate exercise and exposure to altitude could cause hypoxia sufficiently severe to adversely affect the comfort and well being of some people and that the combined effect of exercise and altitude on comfort and well being is greater than the effect of exercise or altitude alone. Again, there is insufficient evidence in the literature to substantiate this possibility. The purpose of this investigation is to test these hypotheses.