Active clinical trials for "Hypoxia"

This study analyses the impairment of colour vision during hypobaric hypoxia in volunteers of different groups.

To compare pulse oximetry saturation measurements, during normal to low saturation, to saturation measurements made by a multi-wavelength CO-oximeter, taken from arterial blood samples from healthy human subjects.

Pulse oximetry offers real time and non-invasive estimation of arterial oxygen saturation in a cost-effective way, and has become a critical tool in guiding the usage of supplemental oxygen in sick newborns. During postnatal transition, pulmonary pressure decreases upon the activation of the lungs, and the ductus arteriosus constricts and closes upon the increase of partial oxygen pressure, which is negatively correlated with altitude. As a result, postnatal transition may be different at high altitudes. Umbilical cord blood gas analysis is now recommended in all high-risk deliveries because of its' value in providing information about preceding fetal hypoxic stress. But there are only limited studies about the SpO2 measurements during the first few hours after birth and umbilical blood gas analysis at high altitudes, especially at altitudes above 2500m. The primary outcome of the study is to determine the reference intervals for preductal oxygen saturation during first 2 hours of life stratified by different gestational age. The secondary outcomes is to establish the pH and lactate cutoff value of umbilical arterial blood gas at different altitude level.

The primary objective is the prospective determination of disease-specific and overall survival in head and neck cancer patients who have undergone surgery, correlated to non-invasive methods of measuring tumour hypoxia. The secondary objective is to define tumour hypoxia using non-invasive methodology.

By integrating a miniaturized pulse oximetry sensor into the frame of oxygen delivery glasses which dissimulates the nasal cannula, the investigators hope to optimize and long term oxygen therapy (LTOT) regarding medical and social aspects. The validation of the novel SpO2 sensor is the first step in the concept of personalized, dynamic delivery of oxygen by eyeglasses using a closed-loop system.

Circulating progenitor cells (CPC) treatments may have great potential for the recovery of neurons and brain function. Our group has reported how exposure to intermittent hypobaric hypoxia with superficial muscle electrostimulation is able to increase the concentration of CPC in peripheral blood in humans. Therefore, we believe that through physical activities and exposure to intermittent hypobaric hypoxia for a period, it will increase CPC in the blood of subjects who have suffered a severe Traumatic Brain Injury (TBI) one or more years ago, promoting regeneration and functional and cognitive recovery. The study primary end-point is to improve physical or psychological functioning of participants with TBI with a program of exercise, muscle electro-stimulation (ME) and/or intermittent-hypobaric-hypoxia (IHH). Secondary end-points are to increase and maintain CPC and also to study their possible relationship with physical or psychological improvement of participants with Traumatic Brain Injury (TBI). In order to achieve these objectives investigators have designed a randomized controlled trial that will include those patients who suffered severe TBI more than one year previously with physical or psychological sequelae. Exercise, muscle electro-stimulation (ME) and/or intermittent hypobaric hypoxia (IHH) programs will be applied during twelve weeks. Psychological and physical stress tests will carry out before and after the program and CPC will measure at the beginning, every two weeks, and at the end of the program.

Adequate perfusion and oxygenation is essential for the function of the inner retina. Although it is known that oxygen tension is very well autoregulated in the retina, the physiological mechanisms behind this regulation process are not fully explored. The development of new instruments for the non-invasive measurement of oxygen tension in retinal vessels now allows for the more precise investigation of these physiological processes. The current study seeks to evaluate the retinal oxygen saturation in healthy subjects while breathing different oxygen mixtures to achieve a hypoxic and a hyperoxic state.

Sedation is needed in order to complete endoscopic retrograde cholangiopancreatography (ERCP) to alleviate discomfort and pain during the procedure. This is usually achieved with use of opioids and/or sedative agents such as benzodiazepines or propofol. Traditionally benzodiazepines have been used but nowadays propofol is becoming the drug of choice for sedation during ERCP. The problem with propofol sedation is the fact that it may case cardiorespiratory depression and there is no antidote for this like there is for benzodiazepines. Cardiovascular depression can usually be easily counteracted with drugs that are used to raise blood pressure or heart rate during general anesthesia but respiratory depression remains a problem. The aim of this study is to try to counteract the respiratory depression caused by propofol sedation using an old respiratory stimulant doxapram as opposed to placebo using a double blind randomized protocol. The investigators hypothesis is that boluses and an infusion of doxapram will alleviate the respiratory depression caused by propofol sedation.

In this study the investigators will investigate the following hypothesis that hypoxia induce migraine headache and migraine aura the aura phase is associated with a spreading reduction in cerebral blood flow the migraine headache is associated with dilatation of intra- and extracerebral arteries the migraine headache is associated with changes in brain metabolism the pre-ictal stage of a migraine attack with aura is associated with specific patterns in neural activity.

The purpose of the study is to assess the effect of progressive, incremental hypoxia at multiple wavelengths of light.