View clinical trials related to Hypoxia.
Filter by:The general aim of this study is to define the response to hypoxic challenge in patients with diabetes. The investigation will provide response for different questions that are central for explaining the development of complications in diabetes - have patients with diabetes an impaired reaction to adapt to hypoxia - what consequence has hypoxia challenge on respiratory and on cardiovascular regulation in patients with diabetes - what consequence has diabetes on the angiogenetic response to hypoxia
Solid tumours often have highly disorganised vasculature that results in low oxygenation. This combined with high metabolic rates leads to oxygen demand outstripping supply causing tumour hypoxia. Hypoxia drives multiple cellular processes involved in the hallmarks of cancer. Tumour hypoxia also decreases the effectiveness of anticancer treatments. This is especially true for patients treated with radiotherapy since it has been long recognised that hypoxic tumour cells require 3 times the dose of radiation to cause the same amount of cell death as cells irradiated under normal oxygen conditions. To date, the majority of attempts at overcoming tumour hypoxia have focused on increasing oxygen supply. However, such techniques have produced modest benefits at best and subsequently have not been adopted into current clinical practice. An interesting alternative approach to tackling tumour hypoxia is to decrease oxygen 'demand' by reducing tumour oxygen consumption. This strategy has been suggested to be more effective in reducing hypoxia than previous methods aimed at increasing oxygen delivery. Pre-clinical data demonstrates that the commonly prescribed anti-protozoal drug atovaquone significantly reduces oxygen consumption in a variety of tumour cell lines in vitro. This reduction in oxygen consumption leads to a profound reduction in tumour hypoxia in animal models. It is anticipated that if these effects on tumour hypoxia could be reproduced in humans, that their tumours could be rendered markedly more sensitive to radiotherapy. This window of opportunity trial will assess whether atovaquone significantly reduces tumour hypoxia in adult patients referred for surgery with suspected non-small cell lung cancer. This will be assessed using a combination of functional imaging and circulating markers of hypoxia. If atovaquone is demonstrated to result in a reduction in tumour hypoxia, larger clinical trials will be conducted to determine whether this well-tolerated and inexpensive agent improves radiotherapy efficacy and clinical outcomes.
Colorectal cancer (CRC) is one of the leading causes of cancer mortality in Canada. Rectal cancers are now known to be hypoxic which is a negative prognostic factor and predictive of metastatic spread and poor responsiveness to treatment. This has also been shown in preclinical xenograft models. Hence there is a need for identification of hypoxic rectal cancers. In this pilot study the investigators intend to non-invasively assess the tumor and nodal metastasis using an integrated Positron Emission Tomography-Magnetic Resonance Imaging scanner (PET/MRI) with 18F-Fluoroazomycin Arabinoside (18F-FAZA) a radiopharmaceutical for assessing tumor hypoxia. The hypoxic rectal tumors will show an increased uptake of 18F-FAZA on PET which will have morphological correlation on MRI. The patient will then undergo neoadjuvant chemoradiation therapy (CRT) followed by repeat 18F-FAZA PET/MRI and rectal cancer surgery with pimonidazole staining. Pimonidazole is an extrinsic marker of hypoxia that is selectively reduced and covalently bound to intracellular macromolecules in areas of hypoxia within normal and tumor tissue with current approval for use in humans for research studies. The primary goal of this pilot trial is to validate FAZA-PET as a biomarker of hypoxia by correlating its uptake in rectal tumors to pimonidazole staining in histopathology specimens. If the investigators pilot study successfully demonstrates the uptake and correlation of pimonidazole and FAZA-PET, the investigators would like to initiate a larger study examining hypoxia in rectal cancer. The investigators aims would be to image patients with locally advanced rectal cancer before CRT to ascertain whether high FAZA-PET uptake correlates with poor outcome to CRT. The ability to preoperatively predict the patient sub-population that will respond best to CRT, will help to identify the "complete pathological" responders and avoid unnecessary surgery. Furthermore, the FAZA-PET high subset of patients may benefit from other treatment strategies including clinical trials of anti-hypoxic agents.
A feasibility study to inform the design and conduct of a randomised controlled trial of high flow nasal cannula (HFNC) versus continuous positive airway pressure (CPAP) for non-invasive respiratory support in critically ill children
This study will test the safety and efficacy of an infusion of a baby's own (autologous) umbilical cord blood as compared with placebo in babies born with history and signs of hypoxic-ischemic brain injury.
The purpose of this study is to characterize the normal brain function of premature infants (23 to 31+6 weeks GA) during birth transition and through the first 72 hours of life.
With exposure to high altitude some individuals will develop acute mountain sickness (AMS). Current evaluation of AMS can make it difficult to rule out other possible conditions. Evaluation of ataxia, as measured by the performance of a coordinated task, can aide in the correct diagnosis of AMS. The investigators have developed novel finger-tapping tasks on a mobile device to assess both reaction time and accuracy. The proposed research will evaluate the utility of this tool in assessing human acclimatization to hypoxia.
The prevention of the occurrence of respiratory events is a constant concern in pediatric anesthesia, as these represent the main cause of the anesthesic mortality. These events occur partly during induction of anesthesia and are all the more frequent as the child is young. The French recommendations do not propose the use of neuromuscular-blocking agents in pediatric anesthesia. This recommendation is controversial In a recently published study, it has been shown that the use of neuromuscular blocking agents during induction in children under 2 years improves intubating conditions and reduces the incidence of hemodynamic and respiratory events. This monocentric study, centered on intubating conditions, does not allow to conclude on the influence of muscle relaxants on reduction of the respiratory morbidity. The objective of study is to demonstrate that, in children under 2 years, changing the anesthesia protocol can reduce the incidence and severity of episodes of hypoxemia associated with respiratory events occurring during induction
Regulation of tissue oxygen homeostasis is critical for cell function, proliferation and survival. Evidence for this continues to accumulate along with our understanding of the complex oxygen-sensing pathways present within cells. Several pathophysiological disorders are associated with a loss in oxygen homeostasis, including heart disease, stroke, and cancer. The microenvironment of tumors in particular is very oxygen heterogeneous, with hypoxic areas which may explain our difficulty treating cancer effectively. Prostate carcinomas are known to be hypoxic. Increasing levels of hypoxia within prostatic tissue is related to increasing clinical stage, patient age and a more aggressive prostate cancer. Several researches indicated that hypoxia might also play a role in esophageal cancer. In glial brain tumors, hypoxia is correlated with more rapid tumor recurrence and the hypoxic burden in newly diagnosed glioblastomas is linked to the biological aggressiveness. In brain metastases CA-IX expression (a marker for hypoxia) is correlated to the primary non-small cell lung carcinomas. Hypoxia enhances proliferation, angiogenesis, metastasis, chemoresistance and radioresistance of hepatocellular carcinoma. The hypoxic markers HIF-1α, VEGF, CA-IX and GLUT-1 were all over expressed in colorectal cancer and its liver metastases. Based on literature, hypoxia in tumors originating or disseminated to prostate, esophagus, brain and rectum cancer will be studied in this trial.
General anesthesia, even in patients in good health, impairs gas exchanges and ventilatory mechanics. These effects result primarily from atelectasis formation. They occur in 85-90% of healthy patients in the minutes following the induction when a positive end expiratory pressure (PEEP) is not used. The functional residual capacity (FRC) of obese patients during general anesthesia is even smaller than the one of healthy patients. There is a direct relationship between the body mass index and the decrease of the functional residual capacity. Obese patients have therefore more atelectasis. The increased abdominal pressure during the pneumoperitoneum will increase the decrease of the CRF, and thus aggravate the formation of these atelectasis. Atelectasis affect the peroperative gas exchanges and are likely to be involved in the worsening of postoperative hypoxemia episodes. In addition, atelectasis alter the clearance of secretions and the lymph flow, which predispose to lung infections.Taking all these factors into account, it is logical to think that the atelectasis presence can lead to an increase of the postsurgical morbidity (respiratory distress, infections). That is why actively fighting against the formation of these atelectasis is important. There is a lack of scientific evidence to say that the strategies against atelectasis as PEEP have a significant impact on the patient's postoperative status. The expected clinical benefits balance (reduction of respiratory distress episodes, infections and mortality) versus the risks linked to the maneuvers done to reduce the development of atelectasis (barotraumas, cardiac complications) remains to be determined. The primary goal of this study is to evaluate the impact of two different alveolar recruitment strategies on the incidence of postoperative hypoxemia in obese patients after bariatric surgery. The secondary objectives of this study are to compare the number of recruitment maneuvers, the Pa02 / FI02 ratio (ratio of arterial oxygen partial pressure to fractional inspired oxygen), the dynamic compliance, the anatomic dead space and intraoperative PaCO2-EtCO2 gradient (arterial and end tidal gradient) between two alveolar recruitment strategies applied in obese patients during laparoscopic bariatric surgery (gastric bypass or sleeve gastrectomy). The tertiary objectives of this study are to report the number of respiratory complications and postoperative wound infections at the 30th postoperative day.