View clinical trials related to Hyperoxia.
Filter by:The inner retina is crucially dependent on an adequate retinal blood supply. When the retina becomes ischemic and hypoxic this results in severe vision loss due to retinal neovascularization. Measurement of retinal blood flow and retinal oxygenation is, however, still a difficult task. Information on retinal oxygenation is almost unavailable from human studies. In the present protocol the investigators propose a procedure allowing for the measurement of retinal blood flow, retinal oxygenation and retinal oxygen extraction by combining a number of innovative techniques. Specifically, retinal vessel diameters will be measured with a Retinal Vessel Analyzer, retinal blood velocities with bi-directional laser Doppler velocimetry and retinal oxygenation with spectroscopic evaluation of retinal fundus images. This will allow for the calculation of retinal oxygen extraction, a fundamental parameter of retinal function. Up to now, no data for retinal oxygen extraction are available in the literature.
Nearly forty years ago Berran and coworkers tested an analog oxygen controller to maintain incubator oxygen levels for infants suffering neonatal respiratory disease in order to prevent hyperoxia. There are at least three clinical issues that this technology addresses: the first is avoidance of episodic hyperoxia; the second is decreasing episodic hypoxia; and the third is lowering cumulative oxygen exposure. Clinical trials which have used target SpO2 ranging probably help improve all of these problems, but so far there have been no direct measurements of continuous arterial oxygen levels, nor clinical studies which establish the degree to which improving control over blood oxygen saturation decreases the cumulative amount of oxygen exposure. This study will address the later and is an important step in the process of incorporating closed-loop oxygen control technology as a routine standard of neonatal respiratory care. OBJECTIVES: PART 1: Test and modify the instruction set for the computerized oxygen controller to achieve a goal of less than six (6) operator required interruptions per hour for oxygen saturation deviations outside of study guidelines. PART 2: Perform a within patient cross-over trial of the computerized oxygen controller versus standard of care (the patient's care team adjusts the patient's oxygen level) and evaluate the area under the time curve for oxygen exposure between the two control methods. PART 3:(After successful completion of PART 2) Continuation of the within patient cross-over study with a randomized cross-over sequence. Studies will last 4 to 12 hours divided in two (2) equal time blocks with one cross-over to either automatic or manual control modes. Provision for up to an additional twenty (20) patients to be studied.
4 times 4 minutes interval training with and without hyperoxia is more effective than low intensity endurance training.
Noninvasive monitoring of blood flow in retinal circulation may elucidate the progression and treatment of ocular disorders, including diabetic retinopathy, age-related macular degeneration and glaucoma. Laser Doppler velocimetry (LDV), a noninvasive optical method combined with vessel size determination has been used extensively as a valuable research tool to examine blood flow dynamics in the human retina. However, no information on the velocity profile within the vessel is available. Ophthalmic color Doppler optical coherence tomography (CDOCT) provides laser Doppler information in addition to conventional optical coherence tomography, allowing the observation of blood flow dynamics simultaneously to imaging retinal structure. We have recently demonstrated the feasibility of Fourier domain CDOCT to assess velocity profiles in human retinal vessels in vivo. In the present study the validity of Fourier domain CDOCT for retinal blood flow measurements will be tested at baseline and during hyperoxia-induced vasoconstriction in humans by comparison with retinal blood flow measurements using a commercially available LDV system and the Zeiss retinal vessel analyzer (RVA)
We assessed the effect of altering inspired gas on the 6MWT distance in COPD. We hypothesized that HeO2 would improve walking distance and reduce shortness of breath compared to both RA and O2, and potentially improve quality of life for COPD patients.