Active clinical trials for "Hyperoxia"

This proof-of-principle study will determine if breathing an increased concentration of oxygen above the concentration in normal room air results in changes in the sensory and motor function in people with subacute or chronic, severe spinal cord injury (SCI).

Prematurely born infants in the hospital neonatal intensive care unit (NICU) will be included in the study. This clinical trial is a randomized crossover study to show that our automated oxygen control device performance is no worse than a NICU nurse in keeping a premature neonate's SPO2 within the prescribed range. Since subjects receive the device (automatic oxygen control) and the standard of care (manual control by a nurse), every subject serves as their own perfectly matched control. Performance measures include the average time it takes for the SpO2 to return to the desired range (primary endpoint) and the total amount of time that the SpO2 is within the desired range (secondary endpoint). The device will be applied to premature infants on respiratory support humidified high flow nasal cannula (HFNC) with oxygen controlled using a blend valve. Two groups include one that begins the study period with the device and one that begins the study period without the device. The two groups are switched between manual and automatic every 6 hours into the trial period and complete a total of 6 days. The target number of subjects is 60. We will analyze the study as a superiority trial if there is strong evidence of superiority.

The impact of oxygen therapy in many pathologies has been subject of recent work, arguing both favourable and harmful effects. Consequently, one can wonder about the influence of hyperoxic gas mixture during diving on the genesis of decompression sickness, but also about the systematic application of normobaric and hyperbaric oxygen in case of proven decompression sickness. In mammals, normoxic concentrations have been redefined at 20-100 mbars at the extracellular level and below 10 mbars in the mitochondria. Under hyperbaric conditions, most of the oxygen being dissolved in blood plasma, a state of hyperoxia is established which escapes the usual delivery and regulation system represented by red blood cells. The results of our team's previous work suggest a specific effect of diving on the levels of circulating mitochondrial DNA (mtDNA), suggesting cellular destruction linked to hyperoxia/hyperbaria. In fact, our studies, carried out on both animals and human divers, have shown that diving accident leads to an increase in mtDNA levels and an immune reaction through the mobilisation of leukocytes. The main objective of this study is to compare the influence of oxygen partial pressure levels on the evolution of clinical and biological variables during hyperbaric oxygen therapy sessions in healthy versus injured divers.

The purpose of this study is to understand how ketogenic food products affect oxygen toxicity in undersea divers. Oxygen toxicity affecting the central nervous system, mainly the brain, is a result of breathing higher than normal oxygen levels at elevated pressures as can be seen in SCUBA diving or inside a hyperbaric (pressure) chamber. This is a condition that may cause a wide variety of symptoms such as: vision disturbances, ear-ringing, nausea, twitching, irritability, dizziness, and potentially loss of consciousness or seizure. Because nutritional ketosis has been used to reduce or eliminate seizures in humans, it may be beneficial to reduce oxygen toxicity as well. The investigators hope this study will provide a help to develop practical and useful methods for improving the safety of undersea Navy divers, warfighters and submariners.

This study is being conducted to compare the incidence of preterm infants (up to 28+6 weeks GA) who achieve a peripheral oxygen saturation of 80 percent by 5 minutes of life (MOL) given mask CPAP/PPV with an FiO2 of 1.0 during DCC for 90 seconds (HI Group) to infants given mask CPAP/PPV with an FiO2 of .30 during DCC for 90 seconds (LO Group).

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 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.

The present study aims to investigate whether FLIO can also detect shorttime changes in retinal metabolism induced by hyperoxia and hypoxia. For this purpose, 48 healthy subjects will be included in the present study and changes in FLIO will be assessed during breathing of 100% oxygen to induce hyperoxia as well as during breathing of 12% oxygen in nitrogen to induce hypoxia. Since stimulation with flickering light also induces a higher metabolic demand in the retina (functional hyperemia), thisprovocation test will also applied during breathing of the different gas mixtures and compared to baseline. To gain information about retinal blood flow, optical coherence tomography angiography (OCT-A) will be performed. The results of the present study can help to gain more insight into the physiology of the retinal metabolism and might give grounds to establish new biomarkers in future studies.

The aim of this study is to identify and determine the levels of oxidized lipids and lipid mediators following exposure to oxygen supplementation during mechanical ventilation by oxidative lipidomics. The investigators will include patients with mechanical ventilation and have received FiO2=>0.5 atleast 90 minutes and collected two sequential mini bronchoalveolar lavage on them 24 hours apart. Mass Spectrometry Lipid chromatography will be conducted and clinical data will be analyzed.

The purpose of this study is to understand how ketogenic food products affect oxygen toxicity in undersea divers. Oxygen toxicity affecting the central nervous system, mainly the brain, is a result of breathing higher than normal oxygen levels at elevated pressures as can be seen in SCUBA diving or inside a hyperbaric (pressure) chamber. This is a condition that may cause a wide variety of symptoms such as: vision disturbances, ear-ringing, nausea, twitching, irritability, dizziness, and potentially loss of consciousness or seizure. Because nutritional ketosis has been used to reduce or eliminate seizures in humans, it may be beneficial to reduce oxygen toxicity as well. The investigators hope this study will provide a help to develop practical and useful methods for improving the safety of undersea Navy divers, warfighters and submariners.