View clinical trials related to Hyperoxia.
Filter by:The purpose of this research study is to understand the effect of nutritional ketosis on CNS oxygen toxicity in undersea divers. The investigators hope this will provide a starting point to develop methods for improving the safety of Navy divers, warfighters and submariners.
The investigators aim to measure the effect of targeting premature babies to a slightly higher oxygen saturation target range (92-97%) than routinely used, for a brief period, to plan a future larger study of the effect of this on clinical outcomes. It is still unclear exactly what levels of oxygen premature babies need - both too little or too much oxygen in the first weeks after birth may be harmful. Previous studies used saturation monitoring (SpO2), where a small probe shines light through the skin and calculates how much oxygen is carried in the blood. These studies demonstrated using an SpO2 range of 91-95% rather than 85-89% was associated with more babies surviving and fewer babies suffering from a bowel condition called necrotising enterocolitis (NEC). However, targeting oxygen higher increased the number of infants who needed treatment for an eye condition called retinopathy of prematurity (ROP). It is possible an SpO2 range higher than 91-95% would be associated with even better survival. It is also possible that a higher range might not improve survival but could increase the need for ROP treatment. Infants born at less than 29 weeks gestation, greater than 48 hours of age and receiving supplementary oxygen would be eligible for inclusion. The study is at the Royal Infirmary of Edinburgh. Total study time is 12 hours for each infant (6 hours at the standard 90-95% range used in our unit, and 6 hours at 92-97%). It is a crossover study with infants acting as their own controls. Based on previous research the investigators are confident these oxygen levels will not be dangerously high. To provide an additional measure of oxygen the investigators will also use a transcutaneous monitor for the 12 hour study period, which fastens gently to the skin and measures oxygen and carbon dioxide levels on the skin surface.
The investigators will conduct a non-randomized clinical trial to examine the effect of pure oxygen breathing on the brain. The study will compare cerebral blood flow, cortical electrical activity, and cognitive performance in 32 persons during room air (21% oxygen) breathing and pure oxygen (100% oxygen) breathing. Subjects will be used as their own controls. The investigators aim to: 1. Determine whether breathing 100% oxygen changes blood flow through the brain. The investigators will learn whether brain blood flow is increased, decreased or stays the same. 2. Determine if changes that might occur in brain blood flow are also accompanied by changes in the brain's electrical activity (EEG). 3. Learn whether changes in the speed at which the brain processes information (cognitive function) accompany changes in brain blood flow and electrical activity that may be seen.
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.
This study aims to evaluate the risk of hyperoxia-induced hypercapnia in post-op obese cardiac surgery patients. It will compare two oxygenation modes in terms of their effect on the arterial partial pressure of carbon dioxide (PaCO2) : manual titration of oxygen delivery for a peripheral oxygen saturation (SpO2) target of > or = 95 % versus automatic titration by a closed-loop system for a SpO2 target of 90%. 15 post-op obese cardiac surgery patients will be recruited and each will receive both interventions (cross-over design). The main outcome will be the PaCO2, which will be compared after each study period. The research hypothesis is that the usual SpO2 target of > or = 95 % is associated with a greater PaCO2 compared with a lesser SpO2 target of 90%.
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.
The hypothesis implies that this work is the use of hyperoxia during cardiopulmonary bypass by his heart preconditioning effect is associated with a lower incidence of cardiac arrhythmias (atrial fibrillation, tachycardia or ventricular fibrillation) and lesions of myocardial ischemia-reperfusion injury in cardiac surgery postoperative.
The aim of this study is to assess whether an auto-titrating oxygen system can maintain constant oxygen saturations (SpO2) in patients who are on long-term oxygen therapy (LTOT) during activities of daily living. Currently LTOT is provided at a constant fixed-flow rate e.g. 2 litres per minute all the time after appropriate assessment. The flow rate is not changed during usual household activities but is increased for walking. A number of studies have investigated the SpO2 of patients on LTOT during the daytime in patients' homes. The results have shown that patients' SpO2 decreases intermittently whilst they are doing activities of daily living such as watching television, putting away the shopping, having a shower or bath and dressing and undressing. This is a problem as it can lead to breathlessness, increased stress on the heart and affect brain function. In order to correct the drop in SpO2 that patients experience during everyday activities, the investigators have developed an oxygen system, which can automatically change the amount of oxygen delivered depending on a patients' oxygen saturations - an auto-titrating oxygen system. In this study, patients on LTOT will be asked to simulate a series of activities of daily living twice: once whilst on their usual fixed-flow oxygen therapy and once on the auto-titrating oxygen system. The activities will be carried out in a hospital setting. During the activities, SpO2 will be recorded continuously. The main outcome of interest from the study will be the SpO2 throughout the study on fixed-flow oxygen and the auto-titrating oxygen system.
A study consisting of a prospective and retrospective cohort in the ICU, ER and pulmonary department in a university hospital in Amsterdam and a teaching hospital in Alkmaar, the Netherlands. The relationship between the oxygen saturation measured by pulse-oximetry and the arterial PaO2 is investigated in order to investigate which transcutaneous saturation values are safe when administering oxygen in relation to hyperopia and hypoxia.
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.