View clinical trials related to Hypoxia.
Filter by:Preoxygenation is recommended before performing tracheal intubation. In intensive care units (ICU) patients, there is no specific recommendation regarding the duration of preoxygenation, which usually is applied for 3 to 5 minutes. Monitoring the effectiveness of preoxygenation with end-tidal oxygen concentration (EtO2) is strongly recommended in the operating room but it is never used in ICUs. The first aim of this pilot study is to assess the effect of the preoxygenation duration on EtO2, and secondarily, as an exploratory objective, to determine whether targeting a given value of EtO2 during preoxygenation might insure a safer intubation than when targeting pulse oximetry (SpO2).
Fetal cardiac monitoring is used during labor. Fetal decelerations may imply fetal hypoxia and distress. Brain activity monitoring is not used to evaluate fetal distress during labor. In this study the investigators intend to use an EEG based algorithm to evaluate and monitor fetal brain activity during the 2nd stage of labor.
Peripheral muscle oxidative function is altered in COPD(chronic obstrutive pulmonary disease) patients. Multiple factors could contribute to this dysfunction including chronic hypoxia and deconditioning (sedentarity). The evaluation of mitochondrial function is based on invasive method (muscle biopsy and in vitro respirometry) or magnetic resonance spectroscopy limited to small muscle groups. Recently, a non invasive method has been described using Near InfraRed Spectroscopy (NIRS). During arterial occlusion, muscle deoxygenation is only dependent of local oxygen consumption. The time constant recovery (k) of the deoxygenation during repeated ischemia periods has been shown to be correlated to measurements of maximal mitochondrial capacity. k is lower in COPD patients compared to smokers without bronchial obstruction. However, the influence of arterial hypoxia has never been studied precisely, no more than the confounding effect of deconditioning on k. So , the aim is to compare k in COPD patients with chronic hypoxemia (treated with long term oxygenotherapy, LTOT+ group) and patients without hypoxia, matched for their physical activity (LTOT- group). The hypothe is that k will be lower in LTOT+ group compared to LTOT- group and that short term O2 supplementation will improve it, which would suggest a muscle hypoxia. By contrast, O2 should not influence k in LOT- group, in whom it is mainly determined by muscle conditioning.
The trial evaluates the value of radiation dose escalation based on Hypoxia detection by 18F_misonidazole Positron Emission Tomography (18F-MISO-PET) for primary radiochemotherapy of head and neck squamous cell carcinoma. Patients negative for human papillomavirus (HPV) and with hypoxic tumours after 2 weeks of radiochemotherapy are randomized to completion of standard radiochemotherapy or radiochemotherapy with escalated radiation dose. An additional interventional arm includes a carbon ion boost. HPV positive tumours can be included in a control arm. Primary endpoint is local tumour control 2 years after radiochemotherapy.
Background and rationale: A large multicenter randomized controlled trial demonstrated that in patients with hypoxemic non-hypercapnic respiratory failure treatment with nasal high flow oxygen (NHF) resulted in a reduction of the endotracheal intubation rate (38%) compared with noninvasive ventilation (NIV) delivered by facemask (50%) or with conventional oxygen therapy (47%), although the difference was not statistically significant. These results could be potentially explained by the physiological benefits provided by the NHF. However, one of the surprising findings of this study was that patients randomized to the facemask NIV group had a similar or even poorer outcome than oxygen alone. Interestingly, an observational study showed that in patients receiving facemask NIV for acute hypoxemia delivered tidal volumes were higher than expected (8.1-11.1 ml/kg predicted body weight), suggesting that NIV could potentially cause ventilator-induced lung injury resulting in worsening respiratory failure. We, therefore, plan a crossover physiologic study investigating the hypothesis that compared with NIV the treatment with NHF of patients with acute hypoxemic non-hypercapnic respiratory failure results in a more homogeneous distribution of tidal volume, and hence less ventilator-induced lung injury, as measured by electrical impedance tomography (EIT). Methods: This physiologic study will enroll 20 patients from the ICU at Toronto General Hospital in one year. Adult patients with acute hypoxemic non cardiogenic respiratory failure and PaO2:FiO2 ≤ 300 mmHg, respiratory rate > 25 breaths/minute, PaCO2 ≤ 45 mmHg and absence of clinical history of underlying chronic respiratory failure will be eligible. Patients that received invasive mechanical ventilation for > 48 hours in the same hospital admission, requiring immediate intubation, with hemodynamic instability (systolic arterial pressure < 90 mmHg after optimal fluid therapy), with Glasgow Coma Scale < 12, or contraindications to noninvasive ventilation and tracheostomy, will be excluded. After baseline assessment while receiving oxygen through facemask or nasal prongs, patients will receive in randomly assigned order NHF for 20 minutes and NIV for 20 minutes, in a crossover manner. EIT recordings, diaphragm ultrasound, and collection of blood samples for arterial blood gases will be performed at the end of each phase. Data analysis: The primary endpoint is the comparison of the EIT intra-tidal ventilation index between treatment with NHF and NIV. As secondary endpoints, we will determine whether NHF, in comparison to NIV, provides respiratory support with lower global inhomogeneity index (EIT), lower tidal volumes, reduces respiratory muscle effort (respiratory rate and diaphragmatic ultrasound), and improves gas exchange (oxygen saturation, PaO2:FiO2, PaCO2, RR).
The imaging of cerebral oxygenation is an extremely important tool in understanding the pathophysiology of the tumor and for adaptation of therapies according to hypoxia. Currently, imaging of cerebral oxygenation is mainly performed by the use of Positron Emission Tomography (PET). Thus, the investigators have been able to show that the FMISO radiotracer can reveal tumor hypoxia (HypOnco study, promotor: Caen University Hospital, main investigator: J.S. Guillamo). After injection of the radiotracer, increased uptake is observed in the regions for which the tissue oxygen pressure is less than 10 mmHg (the healthy brain with a tissue oxygen pressure (ptO2) ≈ 40mmHg). Although PET is a reference methodology, it is not widely practiced mainly because of radioactive sources. Magnetic Resonance Imaging (MRI) would bypass the previously mentioned PET limitations. The investigators have recently shown that a measure of local oxygen saturation could be obtained by MRI. This methodology has also been implemented at a clinical scale on lower field MRI magnets, but its formal validation in a clinical situation remains to be demonstrated with respect to FMISO. The major advantage of this methodology is that MRI is already performed in routine practice for patients. Measuring tissue oxygenation with MRI (SatO2-MRI) would not add additional examination for the patient. In addition, MRI is a non-ionizing methodology with a very good spatial resolution compared to PET, this should help to better understand intratumoral heterogeneity. Similarly, in preclinical studies, the investigators have shown in a context of mild hypoxia that SatO2-MRI may be more sensitive than PET. The investigators propose a study to compare in patients with glial tumors, images obtained by 3 Tesla MRI of SatO2-MRI to the hypoxia maps obtained by FMISO PET. These imaging studies will be confronted with studies carried out in immunohistochemistry on biopsies / resection allowing to reveal and to quantify by image analysis the expression of the factors induced by hypoxia (HIF1, HIF2). This study should include 20 patients with glioma (15 high-grade patients and 5 low-grade patients) in pre-surgery. The aim is to show that SatO2-MRI is a relevant methodology (in terms of sensitivity, specificity) for assessing intratumoral oxygenation in a context of brain tumors. This fits perfectly into an era of personalized medicine where functional imaging finds its meaning.
Obesity is omnipresent problem in everyday anesthesiology practice associated with low level of blood oxygen (hypoxemia) during analgo-sedation. Overweight outpatients are often scheduled for colonoscopy usually undergo analgo-sedation. In obese patients, intravenous analgo-sedation often diminish respiratory drive causing hypoxemia. To avoid hypoxemia, low-flow nasal oxygenation (LFNO) of 2-6 L/min is applied via standard nasal catheter to provide maximum 40 % of inspired fraction of oxygen (FiO2). LFNO comprises applying cold and dry oxygen which causes discomfort to nasal mucosa of patient. LFNO is often insufficient to provide satisfying oxygenation. Insufficient oxygenation adds to circulatory instability - heart rate (HR) and blood pressure (BP) disorder. On the other side, high-flow nasal oxygenation (HFNO) brings 20 to 70 L/min of heated and humidified of O2/air mixture up to 100% FiO2 via specially designed nasal cannula. Heated and humidified O2/air mixture is much more agreeable to patient. HFNO brings noninvasive support to patients' spontaneous breathing by producing continuous positive pressure of 3-7 cmH2O in upper airways consequently enhancing oxygenation. Investigators intend to analyze effect of HFNO vs. LFNO on oxygen saturation during procedural analgo-sedation for colonoscopy in obese adult patients. Investigators expect that obese patients with preserved spontaneous breathing, oxygenized by HFNO vs. LFNO, will be less prone to hypoxemia thus more respiratory and circulatory stable during procedural analgo-sedation for colonoscopy. Obese patients with applied HFNO should longer preserve: normal oxygen saturation, normal level of CO2 and O2, reflecting better respiratory stability. Investigators expect obese participnts to have more stable HR and BP, reflecting improved circulatory stability. There will be less interruption of breathing pattern of obese patients and less necessity for attending anesthesiologist to intervene.
Analgo-sedation is standard procedure in anesthesiology practice and is often given for colonoscopy in the setting of daily hospital. Ideally, patients should be sedated with preserved spontaneous breathing and adequate blood O2 saturation. To maintain adequate oxygenation, low-flow O2 (2-6 L/min) is usually delivered through standard nasal catheter which can provide inspired fraction (FiO2) of 40% (low-flow nasal oxygenation - LFNO). Coldness and dryness of LFNO applied may be uncomfortable to patient. Standardly applied intravenous anesthetics can lead to transient ceasing of breathing and O2 desaturation despite LFNO. Respiratory instability can also potentiate circulatory instability - undesirable changes in heart rate (HR) and blood pressure (BP). Unlike LFNO, high-flow heated and humidified nasal oxygenation (HFNO) is characterized by the oxygen-air mixture flow of 20 to 70 L/min up to 100% FiO2. Warm and humidified O2, delivered via soft, specially designed nasal cannula, is pleasant to patient. HFNO develops continuous positive pressure of 3 to 7 cmH2O in upper airway which enables noninvasive support to patient's spontaneous breathing thus prolonging time of adequate O2 saturation. Aim of this study is to compare effect of HFNO and LFNO on oxygenation maintenance before, during and after standardized procedure of intravenous analgo-sedation in normal weight patients of ASA risk I, II and III. Investigators hypothesize that application of HFNO compared to LFNO, in patients with preserved spontaneous breathing during procedural analgo-sedation, will contribute to maintaining of adequate oxygenation, consequentially adding to greater circulatory and respiratory patients' stability. Investigators expect that patients who receive HFNO will better maintain adequate oxygenation regarding improved spontaneous breathing. Also patients will have shorter intervals of blood oxygen desaturation, less pronounced rise in blood CO2 level and lesser fall of blood O2 level, less change in HR and BP. Investigators will have to exactly estimate partial and global respiratory insufficiency (blood CO2 and O2 levels) associated with LFNO and HFNO, which will be done by blood-gas analysis of 3 arterial blood samples collected before, during and after analgo - sedation via previously, in local anesthesia, placed arterial cannula. Possible complications will be explained in written uniformed consent and by anesthesiologist.
This study will investigate the effects of ketone ester drinks on cognitive performance in hypoxia.
Perinatal asphyxia is common cause of acquired neonatal brain injury in neonates associated with hypoxic-ischemic encephalopathy, leading to long-term neurologic complication or death. In 2000, the neonatal mortality rate in Egypt was found to be 25 per 1000 live birth. In this survey, hypoxic ischemic encephalopathy accounts for 18% of neonatal mortality and is the second most common cause of neonatal death.