Active clinical trials for "Hyperoxia"

Coronary artery disease (CAD) is a condition which refers to the narrowing of the small blood vessels that supplies blood and oxygen to the heart. It is a common cause of chest-pain related symptoms and as a result of a 'heart attack'. In most cases, to assess the severity of the disease is to use coronary angiography, which is a medical imaging technique that uses contrast (a dye) and x-ray to show the blood-flow supply of the coronary arteries. The optimal treatment for patients with symptomatic coronary disease is aggressive medical therapy. Current guidelines recommend patients with symptomatic CAD and severe disease on angiography undergo revascularisation therapy, which aims to restore blood flow to blocked arteries. This can be done by either percutaneous coronary intervention (feeding a small balloon or other device on a thin tube through blood vessels to the point of blockage and then inflate the balloon to open the artery), or coronary artery bypass grafting (open-heart surgery)2. For many symptomatic patients who have only moderate disease on angiography, further functional testing is required to assess the extent of the blockage. This can be achieved by placing a pressure wire to the artery of interest, to determine the likelihood that the blockage impedes oxygen delivery to the heart muscle, known as the Fractional Flow Reserve (FFR)3. FFR is commonly performed at the Alfred hospital in the assessment of such patients. During an FFR procedure, further information regarding the health of the small arteries of the heart can be obtained with the calculation of the index of micro-vascular resistance (IMR), Giving oxygen to patients with CAD is a common clinical practice, especially to all patients in the catheterisation laboratory whose had a 'heart attack' and often administered concurrently with light sedation during elective procedures. Recently, however, the safety of routine supplemental oxygen in patients with CAD has been questioned5. A research study analysed the outcomes of three small randomised studies on oxygen in patients who experienced a 'heart attack', while suggestive of harm, the findings of the study remain inconclusive. There may also be deleterious effects of supplemental oxygen, on more stable patients with CAD, who are not experiencing a 'heart attack'. Supplemental oxygen administered in the catheterisation laboratory to patients with stable CAD, has been shown to significantly reduce coronary artery blood flow and increase its resistance6-8. It has also been shown to reduce cardiac output and effect the relaxation phase of the heart cycle. Based on this data it is hypothesised that supplemental oxygen may affect FFR in patients with moderate CAD. The investigators therefore propose to undertake a study of the effects of supplemental oxygen on FFR in patients with moderate CAD. The patients enrolled into the study will be scheduled for an elective normal contrast diagnostic or interventional procedure as part of their clinically-indicated care. Once a moderate blockage of the artery has been identified, FFR and IMR will be measured. During the first phase of the FFR study, the patient will breathe room air and have a blood test to measure their oxygen level (blood gas). There is a 3 minute washout period, followed by the second phase, whereby the patient will be given 100% oxygen for 10 minutes and have another blood gas measured. The study will be conducted at Alfred Hospital with a total enrollment of 18 subjects. The estimated time to complete enrollment is 6-10 months. Data collected on each patient will include demographics, medical history, vital signs (heart rate, blood pressure, height, and weight), usage of cardiovascular medications, pathology results and procedural records. Any adverse events or serious adverse events related to the study procedure will also be recorded.

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.

Several studies show how patients with hyperoxia after cardiac arrest has increased mortality, but the association of hyperoxia before cardiac arrest and myocardial damage has never been investigated. Neither has the association between hyperoxia after cardiac arrest and myocardial injury. Our research hypothesis is that hyperoxia before cardiac arrest aggravates myocardial damage, secondly we wish to analyze the association between hyperoxia after cardiac arrest and myocardial injury. The exposure variables is oxygenation within 48 hours before and 48 hours after cardiac arrest, our primary outcome is myocardial damage and will be measured as peak troponin within 30 days after cardiac arrest.

The study aimed to evaluate different preoxygenation methods (tidal volume for 3 minutes and 4 deep breaths) in pregnant women with oxygen reserve index (ORI). After the routine monitoring of healthy ASA II pregnant patients between the ages of 18-45, different preoxygenation methods will be applied, and the oxygen status of the patients will be compared with ORI monitoring.

To assess oxygenation with the oxygen reserve index in desflurane anesthesia administration using low and high fresh gas flows for tympanomastoidectomy surgeries.

Prospective analysis included patients, 18 years or older, scheduled for 60 daily HBOT sessions between 2016-2018. Each session was 90 min of 100% oxygen at 2 ATA with 5 minutes air breaks every 20 min, five days per week. Pulmonary functions,measured at baseline and after HBOT,included forced vital capacity (FVC), forced expiratory volume in one second (FEV1), peak expiratory flow rate (PEF).

The main objective is to demonstrate that hyperoxia in cardiac surgery increase the occurrence of post-operative pulmonary complications

The purpose of this study is to determine how intraocular pressure responds to changes in the levels of carbon dioxide or oxygen that a healthy individual inspires.

We made a fortuitous observation of periodic breathing in a healthy subject coming to our outpatient mountain medicine consultation at Avicenne hospital in Bobigny (France). During this consultation, subjects perform a hypoxia exercise test, which allows a good prediction of their risk factors for severe high altitude illnesses. Surprisingly, breath-by-breath recording of the ventilation signal showed a periodic breathing pattern, which increased when the subject started to exercise in hypoxic conditions and was maintained during normoxic exercise. Therefore, our objective was to confirm this observation in a retrospective study led in 82 subjects who passed this test. We tested the hypothesis that subjects with a brisk ventilatory response to hypoxia might show a more pronounced periodic pattern of ventilation, due to a higher gain of the chemoreceptor feedback loop. Then, our objective is to investigate the mechanisms involved in the periodic pattern in healthy subjects, as a function of exercise intensity, altitude intensity, role of peripheral and central chemoreceptors to O2 and CO2. Finally, we want to investigate the possible role of this ventilatory instability in patients with obstructive or central apneas.

Oxygen therapy is administered to all patients during general anesthesia to maintain tissue oxygenation and prevent hypoxia and ischemia. However, liberal use of oxygen may lead to hyperoxia and some studies suggest that supranormal levels of arterial oxygen saturation may lead to complications. In this post hoc substudy of the VISION cohort, we plan to assess the association between perioperative inspired oxygen fraction (FiO2) and myocardial injury after non-cardiac surgery (MINS).