Clinical Research Directory

Study of the Effects of Acute Exposure to Moderate Altitude Hypoxia on Prospective Memory.

The goal of this study is to investigate whether prospective memory, i.e., memory for delayed intentions, is impaired at moderate altitude (4,000m). It will also allow to study the effect of air and oxygen administration during hypoxia exposure. The main questions it aims to answer are: * Does moderate acute hypoxia impair prospective memory ? * If so, does air or oxygen adminsitration induce a restoration of prospective memory? Researchers will compare cognitive performance during normobaric hypoxia exposure to cognitive performance during normoxia (control situation). Participants will: * Session S0. Perform a battery of neuropsychological tests and questionnaires). EEG will be recorded during tests. A cheek swab will be performed. * Sessions S1 and S2. Perform several cognitive tasks while exposed to hypoxia and to normoxia (2 different sessions, randomized order) in a normobaric chamber. These are standardized cognitive tests administered on a computer and cognitive tests embedded in a flight simulator scenario. Various questionnaires will be performed on a regular basis. Several physiological measurements will be performed continuously: EEG, ECG, SpO2 and breathing rate. Blood pressure will be measured at the beginning and at the end of hypoxia/normoxia exposure. A blood sample will also be performed. At last, participants will inhale air or oxygen through a mask while making a cognitive task in the chamber.

The Physiological Effects of Acute and Ramp Simulated Altitude Exposure During Simulated Flight Tasks

• 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

Effect of Acute Hypoxia on RIght VEntRicular Function in HAPE.

More and more people are engaging in sports in the mountains, including individuals with heart or lung diseases. At the same time, such diseases are becoming more common in Switzerland. At high altitude, less oxygen is available, which places stress on the body-particularly on the heart, which has to pump blood through the lungs. How the heart, especially the right ventricle, in people with past HAPE responds to this stress is still not well understood. Therefore, this study investigates how the heart responds to simulated altitudes of 2,500 m and 4,000 m, both at rest and during light physical activity in patients with past HAPE. The primary objective is to assess how right ventricular function changes under conditions of reduced oxygen availability. In addition, vital signs, changes in blood gases, oxygen levels in blood and tissue and shortness of breath are assessed. The "altitude" is simulated using a special gas mixture that participants inhale. Participants undergo three altitude conditions (490, 2,500, and 4,000 m above sea level). The order of the altitude conditions is assigned at random. The aim is to better understand how the right ventricle and other parameters respond to low-oxygen conditions and how affected patients can be better supported in the future.

Effect of Acute Hypoxia on RIght VEntRicular Function in Healthy Adults.

More and more people are engaging in sports in the mountains, including individuals with heart or lung diseases. At the same time, such diseases are becoming more common in Switzerland. At high altitude, less oxygen is available, which places stress on the body-particularly on the heart, which has to pump blood through the lungs. How the healthy heart, especially the right ventricle, responds to this stress is still not well understood. Therefore, this study investigates how the heart responds to simulated altitudes of 2,500 m and 4,000 m, both at rest and during light physical activity. The present investigation focuses on healthy individuals in order to establish a reference for future comparisons with patients suffering from cardiopulmonary diseases. The primary objective is to assess how right ventricular function changes under conditions of reduced oxygen availability. In addition, vital signs, changes in blood gases, oxygen levels in blood and tissue and shortness of breath are assessed. The "altitude" is simulated using a special gas mixture that participants inhale. Healthy participants undergo three altitude conditions (490, 2,500, and 4,000 m above sea level). The order of the altitude conditions is assigned at random. The aim is to better understand how the right ventricle and other parameters respond to low-oxygen conditions and how affected patients can be better supported in the future.

Altitude and Outcomes in Pediatric ARDS: A Multicenter Study

This multicenter observational study will evaluate the association between geographic altitude, availability of critical care resources, and clinical outcomes in children with pediatric acute respiratory distress syndrome (PARDS). Data on demographics, physiology, and hospital structure will be collected from PICUs located at different altitudes worldwide. The study aims to identify gaps in PARDS management and provide recommendations adapted to diverse resource settings.

Effect of Altitude on Iron Absorption in Iron Depleted Women

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.