Active clinical trials for "Hypoxia"

Infants are at risk of developing motor and cognitive neurodevelopmental disabilities as a sequelae to hypoxic-ischemic brain injury during the perinatal period. It is an ongoing challenge to predict the severity and extent of future developmental impairment during the neonatal period. This study will help test the feasibility of conducting a large-scale study that evaluates the role of diffuse optical tomography as a bedside neuroimaging tool in complementing the prognostic value of conventional and diffusion weighted MRI for predicting neurodevelopmental outcome in neonates with perinatal hypoxic-ischemic brain injury.

This WP specifically aims to elucidate the effects of IEK on hypoxic tolerance and the development and severity of AMS symptoms, blood and tissue oxygenation status, as well as sleep quality during an episode of acute exposure to severe hypoxia.

The aim of the current study was to examine the effects of 3-session repeated sprint training performed in a normobaric hypoxic condition with 48-hour rest intervals on sprint performance indices, arterial oxygen saturation (SpO2) and rating of perceived exertion (RPE) scores. Twenty-four moderately-trained males participated in this study voluntarily basis. This study was conducted on single-blind placebo-controlled design. Participants were divided into three groups as follows; normobaric hypoxia (3420 m; HYP), normobaric normoxia (162 m; PLA) and control group (CON). HYP and PLA groups subjected to 3 repeated sprint training session (4 set x 5 x 5 s sprints with 30 s recovery and 5 min rest between the sets) in normobaric hypoxia or normoxia condition. Pre- and pos-test were conducted 72 hours before and after the training intervention period. All the training and testing sessions performed in cycle ergometer. There were no detected significant time and condition interaction in the variables; relative peak power output (PPO), mean power output (MPO), percentage of sprint decrement score (Sdec%) and RPE observed in the scope of pre- and post-test.

The purpose of this clinical study is to validate the SpO2 accuracy of the Stryker Sustainability Solutions pulse oximetry sensors during motion conditions over the range of 70-100% SaO2 as compared to arterial blood samples assessed by CO-Oximetry. The end goal is to provide supporting documentation for the SpO2 accuracy validation of the reprocessed sensors.

The purpose of this clinical study is to validate the SpO2 accuracy of the Stryker Sustainability Solutions pulse oximetry sensors during non-motion conditions over the range of 70-100% SaO2 as compared to arterial blood samples assessed by CO-Oximetry. The end goal is to provide supporting documentation for the SpO2 accuracy validation of the reprocessed sensors.

Brain oxygenation is determined by the product of CaO2 and the cerebral blood flow (CBF), the modification of one or the other can affect the neuronal O2 availability. Besides the effect of the PaO2, the CBF is also regulated by the PaCO2. During effort in state of hypoxia, the drop of the PaO2 associated to a potential decrease of the PaCO2 and therefore of the CBF, can create an important dizziness between the demand and the supply of cerebral O2. It seems that hypoxia can trouble in a significant way the response of central neurons, just as the production of a motor cortex generated motor command. Studies suggest that exercise in severe hypoxia condition can constitute a necessary threat for brain oxygenation and the motor command, with the consequence a decrease of the exercise performance. This projects aim to study effects of hypoxia on the brain function for patients suffering from chronic respiratory disease. Neurophysiologic responses of the brain while resting or exercising, including drip and cerebral oxygenation, cortical excitation and motor command resulting for hypoxic subjects before and after a treatment to correct abnormalities of gaz in blood. The study will use a multidisciplinary and supplementary methodological approach : the near-infrared spectroscopy (NIRS) to appreciate the drip and cerebral oxygenation, CBF, neurostimulation procedures and electromyography (EMG) to appreciate the cortical excitability, measure the level of central activation and motor command. The goals of this study will be : Measure the drip and cerebral oxygenation, the cortical excitability, mechanisms of voluntary activation and central fatigue to the effort for the chronic hypoxemic patient compared to healthy control subjects. Analyse disruptions of locomotion parameters and posturographyc, in simple and double task, involving different levels of cerebral task. Analyse acute effects of an improvement of arterial oxygenation for patients suffering from chronic obstructive pulmonary disease (COPD) on drip and cerebral oxygenation, cortical excitability, mechanisms of voluntary activation and central fatigue. Evaluate effects of a treatment by continuous positive airway pressure (CPAP) for patients suffering from obstructive sleep apnea (OSA) with the same parameters.

A loss of body weight has been documented in lowland-living individuals when exposed to hypoxic environments, such as at high altitude, or under laboratory conditions. A reduction in appetite and energy intake has also been reported during conditions of microgravity, such as during space flight. Fourteen normal or over-weight men, who are otherwise healthy, will undergo 3x 21-day interventions; normobaric normoxic bed rest (NBR; FiO2=21%), normobaric hypoxic ambulatory confinement (HAMB; FiO2=14%; ~4000 m simulated altitude), and normobaric hypoxic bed rest (HBR; FiO2=14%). The effects of hypoxia and bedrest on appetite and its hormonal control will be assessed before and at day 17 of each intervention using a mixed meal tolerance test.

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.

During exercise in conditions of low oxygen (termed hypoxia), such as mountaineering at high altitudes, the lung blood vessels constrict in an attempt to protect the body from the negative effects of hypoxia. It appears that this blood vessel constriction may limit the heart to pump blood during heavy exercise, leading to reductions in exercise performance. Inhaled nitric oxide is a drug that is known to relax the lung blood vessels. Inhaled nitric oxide has been used to relax lung blood vessels and improve exercise capacity in patients with chronic disease. It is unknown if similar improvements would be observed during exercise in healthy individuals when exposed to low levels of oxygen. The goal of this study is to determine if inhaled nitric oxide can relax the lung blood vessels and improve the heart's pumping ability during exercise in low oxygen conditions. Further, the investigators will determine if these improvements in lung blood vessel and heart function increase exercise performance. Participants will complete 6 sessions over a three week period where they will perform exercise challenges while breathing low levels of oxygen with and without inhaled nitric oxide. The low oxygen conditions will be comparable to being at an altitude of 14,000-17,000 feet. 17,000 feet would be equivalent to standing on the summit of King Peak in the Yukon (the 4th tallest mountain in Canada).

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.