Active clinical trials for "Hyperoxia"

The purpose of this study is to find out a serum marker for the evaluation of blood brain barrier damage based on animal experiments and investigate the effect of NBO（Normobaric hyperoxia）on blood brain barrier in the acute ischemic stroke patients who received r-tPA thrombolytic therapy.

The purpose of this study is to test the hypothesis that decreasing the inspired oxygen concentration during thoracic surgery requiring one lung ventilation will improve post-operative oxygenation.

Recently, hyperoxia has been recognized as being potentially deleterious for critically ill patients, with increased duration of mechanical ventilation and even with increased mortality rates. This could be related to pulmonary lesions (including notably atelectasis) but also to increased tissue damage and organ dysfunctions, secondary to increased/induced oxidative stress. At last higher FiO2 led to "over-consumption" of oxygen and therefore to additional costs. Usually, FiO2 and oxygen flows are modified according to the monitoring of SpO2. But, it has also been recognized that modifying FiO2 (and oxygen flows) according to SpO2 monitoring is not routinely (or easily) done. Indeed, nurses (and doctors) are reluctant to reduce oxygen flows when everything appear under control. The ORI (Oxygen Reserve Index) is an index measured using non-invasive SpO2 sensors (Rainbow sensors- MASIMO) that evaluates non-invasively PaO2 (partial pressure of oxygen). An ORI ≤0 indicates that PaO2 is less than 100 mmHg. When ORI increases (i.e. ORI≥0.01) PaO2 is higher than 100 mmHg. This index increases up to 1. ORI between 0.01 and 1 indicates that PaO2 is probably between 100 and 200 mmHg. Thus, monitoring critically ill patients using the ORI, may help identifying when PaO2 is high and when FiO2 (or oxygen flows in non-intubated patients) may be reduced. This could help reducing the time with hyperoxia (i.e. PaO2 ≥100 mmHg or ≥80 mmHg). The purpose of this feasibility study is to evaluate if the use of ORI can help to decrease length of moderate hyperoxia (PaO2>100mmHg) in critically ill patients, in comparison with monitoring the SpO2 only.

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)

High arterial blood oxygen tension leads to vasoconstriction of retinal vessels, possibly related to an interaction between reactive oxygen species and endothelium-derived vasoactive factors. Vitamin C is a potent antioxidant capable of reversing endothelial dysfunction due to increased oxidant stress. Vitamin C appears to have vasodilatory properties, but the underlying mechanisms are not well understood. In the present study we hypothesized that hyperoxic vasoconstriction of retinal vessels could be diminished by vitamin C. Ocular blood flow will be determined by non-invasive methods, including laser Doppler velocimetry and the Zeiss retinal vessel analyser.

The aim of the study is to investigate a possible correlation between the change in PCO2 during a hyperoxia-test and the change in PCO2 during walking in people with COPD

This is a randomized, prospective controlled trial in patients undergoing cardiac surgery, specifically on-pump coronary artery bypass grafting, comparing level of administered oxygen and partial pressure of arterial oxygen in the operating room and its impact on a widely-used and validated neurocognitive score, the telephonic Montreal Cognitive Assessment (t-MoCA), throughout the hospital stay and at 1 month, 3 months, and 6 postoperatively. It is hypothesized that cardiac surgical patients who undergo normoxic conditions throughout the intraoperative period will have better neurocognitive function than those with maintenance of hyperoxia.

The major objective of the present study is to examine the influence of normobaric hyperoxia treatment on the symptoms of patients diagnosed with depression members of Clalit Health Services. The investigators hypothesize that normobaric hyperoxia treatment will improve the symptoms of patients with depression.

Prospective observational study in 40 adult critically ill patients. Patients were eligible if they were mechanically ventilated with an FiO2 ≤0.5 and PaO2/FiO2 ≥200 mmHg and hemodynamically stable with a hemoglobin ≥9 g/dL, no acute bleeding or need for blood transfusions, no renal failure, no chronic obstructive pulmonary disease. Twenty patients (hyperoxia group) underwent a 2-hour exposure to normobaric hyperoxia (FiO2 1.0), 20 patients were evaluated as controls. Serum erythropoietin (EPO) was measured at baseline, 24h and 48h. Serum Glutathione (GSH) and reacting oxygen species (ROS) were assessed at baseline (t0), after 2 hours of hyperoxia (t1) and 2 hours after the return to baseline FiO2 (t2). Sidestream dark field videomicroscopy was applied sublingually to assess the microvascular response to hyperoxia. Near infrared spectroscopy with a vascular occlusion test was applied at t0, t1, t2.

Pulmonary Hypertension (PH) is a severe disease with a bad prognosis. However, thanks to extensive research in this field, there are more and better treatment options that allow patients to participate in recreational activities at moderate altitude or bring up the question of air-travel. Still very few is known about the effects hypoxic conditions have on PH patients. The aim of this study is to investigate the effects of hypoxia in comparison to normoxia and hyperoxia on pulmonary hemodynamics in patients with pulmonary hypertension during routine right heart catheterisation. We aim to get insight into the pathophysiology of pulmonary hemodynamics under hypoxic conditions in comparison to normoxia and hyperoxia in patients with pulmonary arterial and chronic thromboembolic pulmonary hypertension compared with control patients, that are scheduled for right heart catheterisation due to dyspnea but have no PH.