Active clinical trials for "Hypoxia"

The purpose of this research study is to better understand how blood flow and metabolism are different between normal controls and patients with disease. The investigators will examine brain blood flow and metabolism using magnetic resonance imaging (MRI). The brain's blood vessels expand and constrict to regulate blood flow based on the brain's needs. The amount of expanding and contracting the blood vessels can do varies by age. The brain's blood flow changes in small ways during everyday activities, such as normal brain growth, exercise, or deep concentration. Significant illness or physiologic stress may increase the brain's metabolic demand or cause other bigger changes in blood flow. If blood vessels are not able to expand to give more blood flow when metabolic demand is high, the brain may not get all of the oxygen it needs. In less extreme circumstances, not having as much oxygen as it wants may cause the brain to grow and develop more slowly than it should. One way to test the ability of the blood vessels to expand is by measuring blood flow while breathing in carbon dioxide (CO2). CO2 causes blood vessels in the brain to dilate without increasing brain metabolism. The study team will use a special mask to control the amount of oxygen and carbon dioxide patients breath in so that we can study how their brain reacts to these changes. This device designed to simulate carbon dioxide levels achieved by a breath-hold and target the concentration of carbon dioxide in the blood in breathing patients. The device captures exhaled gas and provides an admixture of fresh gas and neutral/expired gas to target different carbon dioxide levels while maintaining a fixed oxygen level. The study team will obtain MRI images of the brain while the subjects are breathing air controlled by the device.

The aim of the study is to compare the accuracy of peripheral blood oxygen saturation measurements using smartwatches from three manufacturers compared to a standard medical pulse oximeter.

The use of acute intermittent hypoxia (AIH) has been examined in animal and human studies to gain an understanding of its effect on spinal excitability and synaptic strength. Subsequently, the investigators have learned that the use of AIH results in new protein formation and spinal plasticity. The use of acute intermittent hypoxia demonstrates a potential for therapeutic utilization in individuals with neurologic injuries. However, little is known about the effect of AIH in healthy individuals. This work is necessary to understand the mechanisms of AIH-induced plasticity. As such, this research study seeks to evaluate the impact of a single session AIH on upper extremity motor function in healthy individuals.

The aim of the project is to experimentally determine the effect of the choice of finger for the placement of a pulse oximeter sensor on the results of measuring peripheral blood oxygen saturation (SpO2) in a healthy person with short-term hypoxia and hypercapnia.

This study evaluates the effect of hypoxia on blood volumes during Antarctic winter-over confinement. Half of the participants will be evaluated during sea-level winter-over confinement, while the other half will be examined during high-altitude hypoxia winter-over confinement.

The aim of the project is to evaluate the effect of hypercapnia on physiological parameters in a healthy person during short-term hypoxia and hypercapnia.

At altitude, humans are exposed to environmental hypoxia induced by the decrease in barometric pressure. On duty or in training, mountain troops, paratroopers or aircrew are regularly exposed to altitude. The effects of altitude on humans occur gradually from 1500 m and depend on both the duration of exposure and the altitude level. Cognitive disorders can occur from 3500 m (threshold of disorders) but there is a very large inter-individual variability. The countermeasure to altitude hypoxia is oxygen but its use is not systematic between 3000 and 4000 m. Its use depends on the duration of exposure, without clearly established standards. Incapacitating effects on the operational capacity and health of soldiers can therefore occur as early as 3500 m. In operations or during training, altitude exposure is often associated with a significant sleep debt (particularly during night or early morning missions), jet lag or precarious rest conditions in overseas operations. These sleep restrictions promote the degradation of mental performance with effects similar to those observed in hypoxia. The combination of these constraints induces a physiological stress which can favour alterations in mental performance, an increase in incapacity, intolerance to altitude or the occurrence of altitude-related pathologies in military personnel. This could occur in particular in the operational zone around the threshold of disorders (3500 m) where the indication of oxygen is discussed. The objective of this study is to assess the impact of acute sleep restriction on hypoxia tolerance.

The primary objective of this project is to examine the efficiency of intermittent hypoxia-hyperoxia conditioning (IHHC) protocol to improve vascular health and reduce blood pressure in hypertensive patients (stage 1). The result of the present study will investigate if IHHC could be a therapeutic treatment for hypertensive individuals. The investigation is designed with a placebo intervention (air ambient) and a control group (age-matched healthy participants). The interest of short cycles of intermittent hypoxia-hyperoxia is due to the triggering of the vasodilatory response in a greater extent compared to the pressor mechanisms since the exposure duration remains short. Therefore, it can be hypothesized that control and hypertensive groups achieving IHHC may exhibit a decreased blood pressure compared to the control and hypertensive groups achieving placebo intervention. The control group may show greater change than hypertensive due to higher vascular reserve. The secondary objective of the study is to understand the underlying mechanism of the beneficial effects of IHHC, especially the role of blood hemorheological changes. Based on available literature, it is know that hypoxia induce an increase in blood viscosity. One may hypothesize that with such a short hypoxic dose used during IHHC, only minor change in blood viscosity may occur. However, a slight rise in blood viscosity is known to stimulate NO synthase and then to produce more NO. Hence it could be one of the mechanisms involved in the early vasodilatory response to hypoxia. These findings are in line with the reported higher NO end-product metabolites during exercise in normoxia and hypoxia in subjects who showed a rise in blood viscosity after exercise. The hypothesis is that the magnitude of IHHC beneficial effects is related to change in blood viscosity and its determinants.

Intubation in the intensive care unit is a standard procedure with a high risk of adverse events such as hypoxaemia and cardiovascular instability. However, it is demonstrated that HFNO (High Flow Nasal Oxygen) for pre and perioxygenation is feasible and, in many situations, prolongs the safe apnoeic period after anaesthesia induction. Previous data of the use of HFNO during intubation of the critically ill is conflicting. With the new device Optiflow Switch, which allow its combination with NIV or tight facemask with perioxygenation, we aim to evaluate whether this could reduce intubation-related hypoxaemia and other adverse events. The general purpose of this project is to compare the addition of Optiflow Switch for pre- and perioxygenation to traditional preoxygenation using a tight-fitting mask or NIV during intubation in adult intensive care patients in a prospective before-and-after study design.

The type of this study is an observational prospective study. It will be done to determine the oxygenation status of the intercostal muscles and quadriceps femoris muscle during exercise in patients with fibrosing lung and to examine its relationship with exercise capacity, respiratory functions and respiratory muscle strength. The main questions that the study aims to answer are: Question 1: Do changes in muscle oxygenation during exercise affect respiratory functions in patients with Fibrosing Lung? Question 2: Do changes in muscle oxygenation during exercise affect exercise capacity in patients with Fibrosing Lung? Participants; demographic information such as age, height, weight will be questioned. Respiratory functions will be evaluated with a desktop spirometer, peripheral muscle strength measurement will be evaluated with a digital myometer, and functional capacity will be evaluated with a 6-minute walk test (6MWT). The Moxy device, which is a non-invasive near-infrared spectroscopy (NIRS), will be attached to the upper leg (the vastus lateralis of the quadriceps muscle) and the rib (intercostal muscles) with a silk patch, and the oxygenation of the muscles here will be measured during the 6-minute walking test. In addition, fatigue status will be evaluated with the Modified Borg Scale.