Active clinical trials for "Hypoxia"

Cyclic Variation in Altitude Conditioning (CVAC) is a new technique that uses a pod-like device to expose users to controlled fluctuations in air pressure. It is designed to promote quicker altitude acclimatization, thus promoting improvements in exercise capacity at altitude and, possibly, at sea level. However, over the past few years, anecdotal stories from users of the device suggest that the CVAC treatments might be causing changes beyond the expected endurance exercise performance benefits. Therefore, the purpose of the study is to obtain data on some of the previous anecdotal claims regarding the device (e.g. increases in strength, improved glucose tolerance, reduction of neuropathic pain and decreased joint swelling) as well as to obtain broad questionnaire data in order to identify more specific variables to investigate in future studies.

The purpose of the study is to evaluate the state of bone health of brain injury patients being seen within a rehabilitation setting. Osteopenia is a condition of bone in which decreased calcification, decreased density, or reduced mass occurs. Osteoporosis is a disease in which the bones become extremely porous, are subject to fracture, and heal slowly. More specifically, the prevalence of osteopenia and osteoporosis at specific anatomic locations (e.g., forearms, hips, spine) will be determined as will specific interventions (e.g., use of vitamins, nutritional supplements, specific prescription medications) that people with brain injury may be applying, or have applied, to manage their bone health. An attempt will also be made to evaluate severity of brain injury, based on loss of muscle strength/function, and to compare this data with bone-focused information such as bone mineral density (BMD), falls, and history.

The purpose of this study is to determine whether dipyridamole enhances postocclusive reactive hyperaemia by increasing extracellular adenosine concentrations during ischemia and reperfusion. Furthermore we hypothesize that dipyridamole augments postocclusive reactive hyperaemia by increasing adenosine receptor stimulation.

Congenital heart disease is a major cause of morbidity and mortality in infants. Many cardiac defects require surgical palliation or repair in the newborn period. The effects of chronic hypoxia on growth and development are unclear. Infants with very severe cardiac defects may undergo surgery in infancy, but often this cardiac surgery can provide only palliation, not correction. As a result, these infants are exposed to a physiology of chronic hypoxia during the neonatal period through infancy, a critical period of growth and development. The optimal oxygen saturations for infants with palliated cardiac defects is unknown. The purpose of this study is to analyze the growth and development of infants with post-surgical palliation in infancy and assess variations in oxygenation saturations and hemodynamics as they relate to weight gain, linear growth and increases in head circumference during the first three years of life.

This feasibility exploratory study objective is to assess the ability of combined MRI BOLD and 18F-MISO PET imaging to visualize tumor hypoxia compare to histological results obtained after radical prostatectomy in order to, in time, be able to identify patient with bad prognostic and to offer them the best therapeutic strategy.

When used with a different radioactive tracer called FMISO, a PET scan can find areas of low oxygen in the tumor. We think that having areas of low oxygen is a reason why some tumors are hard to treat with radiation. In a past study, FMISO PET scans were performed in 6 patients with rectal cancer that could not be operated on and that had spread to other areas. In this group of patients, FMISO PET scans were able to find the low oxygen areas in their tumors. But this study included only a few patients. In the present study, we want to use FMISO PET scans in patients who have tumors that can be operated on. This group of patients will have radiation, chemotherapy or both before they have their surgery. We want to see if FMISO PET can find low oxygen areas in this distinct group of patients.

The purpose of this study is to determine whether an experimental alternative imaging method, Near Infrared Spectroscopy (abbreviated as NIR), can be used with a controlled respiratory system to examine the breasts for cancer. The NIR system uses light beams to produce an image or picture of the inside of the breast. The respiratory system will help researchers get more information about the breast tissue by changing the amount of oxygen the tissue receives during NIR imaging.

66% of HNC patients present with advanced-stage disease at initial diagnosis. The 5-year survival rates for stages IVa, IVb, and IVc are 32%, 25%, and <4% respectively. Accurate pre-treatment staging is vital in determining the optimum procedure for the management of HNC. Early identification of non-responders may allow modification of their treatment through the introduction of more intensive therapies. Identifying prognostic factors that predict patient outcome will ultimately lead to new treatment regimens. Tumor hypoxia and proliferation are two key characteristics of cancer that were shown to correlate with poor response to treatment in HNC. In this proposal, the investigators assess the prognostic values of these two markers. Combining information from these two biological markers shall result in prognostic information superior to those of any of the two separately. Imaging those vital tumor characteristics simultaneously shall provide more coherent assessment of tumor microenvironment than does registration of corresponding images acquired in different imaging session, thus subject to uncertainties resulting from transient biologic changes and image registration process. The investigators propose to use a method that the investigators previously developed to simultaneously and non-invasively image tumor hypoxia (FMISO-PET) and proliferation (FLT-PET) within a single PET/CT study. CT Perfusion scan will be performed 1st, followed by PET imaging with staggered FMISO and FLT injections. FMISO and FLT signals will be separated retrospectively using kinetic modeling. The investigators believe imaging tumor hypoxia and cell proliferation simultaneously yield information underpinning for image-guided and radiobiological based dose painting, adaptive therapy, and patient medical management. If successful, this pilot study will constitute the basis for a NIH grant proposal that aims to improve treatment outcome assessment in HNC.

A longitudinal study evaluating the predictive ability of near infrared spectroscopy to predict brain injury in infants with hypoxic ischemic encephalopathy. Data will be analyzed at two different time periods, at discharge and again at 2 years of age.

Transfusion of red blood cells is an everyday practice in critical care with the primary aim of restoring adequate tissue oxygenation. However, blood transfusion may also be harmful and costly, therefore a so called restrictive transfusion regime has been suggested by recent guidelines. These transfusion guidelines consider certain levels of hemoglobin as transfusion trigger, which on its own gives little information if any about the balance between oxygen delivery (DO2) and consumption (VO2). Hence, there is a clear need for additional physiologic transfusion trigger values. One of the potentially useful and easily obtainable physiological parameters is the central venous oxygen saturation (ScvO2), which has been shown to be a potential transfusion trigger value in hemodynamically stable but anemic patients. However, the role of ScvO2 as a transfusion trigger value was examined only in a retrospective observational study and in animal experiment. The normal value of ScvO2 in a resting adult at rest is around 70-75%, which is the product of the VO2 and DO2 relationship. Low ScvO2 usually indicates inadequate DO2. It was found in an observational study that if ScvO2>70% before transfusion due to transfusion only the value of hemoglobin increased but the value of ScvO2 did not change. This finding indicates that the DO2 may have been adequate in spite of the low hemoglobin value and the transfusion may have been unnecessary. In one of their recent animal experiments, the investigators reported that in an isovolemic-anemia model the value of ScvO2<70% was only reached when the value of hemoglobin was far less, 59 g/L, than the recommended lowest value of 70g/L as transfusion trigger by guidelines. Despite the pathophysiological rationale and the encouraging results of retrospective studies and animal experiments, prospective randomized trials in order to test the effects of an ScvO2-assisted transfusion protocol are yet to be performed. The aim of this study is to investigate the effects of an ScvO2-assisted transfusion protocol as compared to the guideline-based, hemoglobin levels guided transfusion practice.