View clinical trials related to Anoxia.
Filter by:Prospective, randomized clinical multicentric study, in ICU, during preoxygenation for the intubation of hypoxemic patients. Electrical impedance tomographic evaluation of lung morphology variations according to the preoxygenation technique : Comparison of Standard Oxygenation, High Flow Nasal Oxygen Therapy, and NonInvasive Ventilation
Evaluate the performance of 4 pulse oximeters in 10 healthy adult volunteers with three motions compared to non-motion control at three arterial oxygen saturation target plateaus.
Near-infrared spectroscopy (NIRS) functions in a manner similar to pulse oximetry, using the difference in absorptive qualities of oxy- and deoxyhemoglobin to infrared light to quantify the percent saturation. There is also available evidence shows that tissue oximetry is sensitive and has a quicker response to physiological derangement, such as bradycardia, in preterm newborns. Additionally, it is demonstrated that reduced postoperative cerebral tissue oxygenation index variability in neonatal survivors of congenital heart disease surgery with poor neurodevelopmental outcomes. The SafeBoosC phase II randomized clinical trial hypothesizes that the burden of hypo- and hyperoxia can be reduced, and consequently the risk of brain injury, by the combined use of close monitoring of the cerebral rStO2 and an evidence-based treatment guideline to correct deviations in rStO2 outside a predefined target range. In this study, we will monitor 2 different tissue beds including cerebral and abdominal somatic tissue rStO2 and SpO2 in neonates. Further research is needed to investigate clinical implications for using this measure to drive therapeutic interventions.
Not uncommonly, sports events take place or finish at high altitude, where physical and cognitive (e.g. decision-making, motor control) performance in hypoxia is determining the outcome of sports performance. With nutritional supplements growing in popularity in the athletic and non-athletic population, research is increasingly focussing on dietary constituents which can improve cognitive and exercise performance. Flavonoids, a subgroup of polyphenols, are a class of natural compounds found in the human diet and include subcategories of flavanols, flavonols, iso-flavones, flavones, and anthocyanidins. Intake of flavanols, found in grapes, tea, red wine, apples and especially cocoa, causes an nitric oxide (NO)-mediated vasodilatation and can improve peripheral and cerebral blood flow (CBF). For cocoa flavanol (CF), there is evidence that both long term and acute intake can improve cognitive function, with the quantity and bioavailability of the consumed CF highly influencing its beneficial effects and with higher doses eliciting greater effects on cognition. Increased CBF following acute and chronic (3 months) CF intake has been demonstrated in healthy young subjects. Moreover, cognitive performance and mood during sustained mental efforts are improved after acute CF intake in healthy subjects and CF intake can increase prefrontal oxygenation during cognitive tasks in well-trained athletes. Moreover, CF intake is not only associated with an improved blood flow, but it might also improve exercise performance following 2 weeks of dark chocolate intake. On top of that, CF is known to have anti-oxidant properties and 2 week CF intake has been associated with reduced oxidative-stress markers following exercise. In hypoxic conditions, arterial pressure of oxygen (PaO2) and arterial saturation of O2 (SaO2) are decreased, compromising tissue oxygen delivery. Since brain function and brain integrity are dependent on continuous oxygen supply, brain desaturation may result in an impaired cognitive function in hypoxia. The severity of the impairment is related to the extent of high altitude, with at 3000m (=14.3 % oxygen (O2); = 71% of oxygen available at sea level) psychomotor impairments being visible. Cerebral oxygenation, which can be measured by Near-infrared spectroscopy, is lowered in hypoxia. It remains unclear whether CF intake can influence cerebral oxygenation and perfusion in hypoxic conditions and whether CF intake could (partially) counteract hypoxia-induced cognitive impairments. Therefore, the first aim of this study was to investigate whether cognitive function and prefrontal oxygenation during a mental demanding task will be impaired by hypoxic conditions (3000m altitude; 14.3% O2) and whether these impairments can be partially restored by subchronic CF intake (7 days, 900 mg/day). Hypoxia also impairs physical performance. Hypoxia-induced reductions in cerebral oxygenation may favour central fatigue, i.e. the failure of the central nervous system to excite the motoneurons adequately, hence impairing exercise performance in hypoxic conditions. Since hypoxia also impairs oxygen delivery to muscle tissue, the decreased oxygen supply to and impaired oxidative energy production in the exercising muscle is a second factor negatively affecting exercise performance. Besides the aforementioned effects of altitude on O2 delivery, hypoxia also results in increased oxidative stress. Oxidative stress refers to the imbalance between prooxidant and antioxidant levels in favor of prooxidants in cells and tissues and can result from diminished antioxidant levels or increased production of reactive oxygen species. The latter can be induced by both exhaustive exercise and high altitude. Since oxidative stress can be counteracted by CF, we also aim to investigate how markers of oxidative stress can be affected by CF intake by exercise in hypoxia. Therefore, the second aim of this study was to investigate possible beneficial effects of CF intake on changes in cerebral and muscle vasoreactivity and oxidative stress during exercise in hypoxia and its implications on exercise performance.
Objectives: Resveratrol, a non-flavonoid polyphenol, has been found to consistently modulate cerebral blood flow (CBF) following oral supplementation. Although, this has not resulted in subsequent predicted benefits to cognitive performance in young healthy populations. However, it is argued that those who suffer a reduction in CBF and cognition, such as aging populations, may benefit more from resveratrol administration. Hypothesis: The current investigation aimed to employ a mild hypoxia as an experimental model of aging in a young healthy population, to assess if resveratrol can attenuate the deficits elicited by the reduction in oxygen supply. It was hypothesized resveratrol would module CBF, to provide a more efficient supply of oxygen to overcome any associated decreases to performance caused by the hypoxic model. Design: This repeated measures, double blind, placebo controlled, balanced design assessed the cognitive and CBF effects of resveratrol in hypoxia (equivalent to ~2000m above sea level) and normoxia (sea level). Methods: 24 participants arrived fully fasted (except water) for 12 hrs before completing a baseline measure of a cognitive task battery, and taking the treatment for the day. Following a 45 min absorption period, participants completed 3 full repetitions of the cognitive test battery and, if appropriate, the oxygen level was altered. Changes in CBF were measured by near-infrared spectroscopy throughout the full testing session.
The purpose is to investigate how the adenosine affects the diameter regulation of retinal arterioles during changes in oxygen tension. A deeper understanding of the mechanisms involved in diameter regulation of retinal arterioles during changes in oxygen tension can be used to obtain a more detailed understanding of diseases where changes in the diameter regulation of retinal vessels are involved in the disease pathogenesis and possibly point to new therapeutic options for patients with retinal vascular disease, such as diabetic retinopathy and retinal vein thrombosis. Preliminary, a routine ophthalmological evaluation, measurement of blood pressure, and electrocardiogram will be preformed to insure that only healthy test persons are included in the study. The test persons will be randomly allocated to two groups, one group in which protocol 1 is followed by protocol 2, and the other group with the two protocols performed in the reverse order. Protocol 1: Using the DVA, a video recording will capture the diameter of retinal vessels and the changes occurring during stimulation with flickering light. The recording lasts 4.5 minutes and is preformed before and after intravenous injection of adenosine. Protocol 2: The procedures are similar to those of protocol 1 but are performed during breathing of a gas mixture with a reduced oxygen tension to 12,5 %, which results in a reduced oxygen saturation in the blood to 85-90 %.
This study is intended to evaluate performance of the new design sufficiently to support performance claims for an FDA 510K submission or ISO technical file. Specifically: - SpO2 value range 70% to 100% - 10 or more subjects, at least 3 of dark pigmentation - At least 200 data points - Meeting the following test required by the 2013 FDA Guidance on Pulse Oximeters - Premarket Notification Submissions and by ISO 80601-2-61 on Pulse Oximeters: - 2013 FDA Guidance on Pulse Oximeters - Premarket Notification Submissions: - 4.1. ACCURACY OF PULSE OXIMETERS - 4.1.1 IN VIVO TESTING FOR SPO2 ACCURACY UNDER LABORATORY CONDITIONS - ISO 80601-2-61:2011 Annex EE.2 and clause 201.12.1.101.2 - 201.12.1.101 SpO2 accuracy of pulse oximeter equipment - 201.12.1.101.2 Determination of SpO2 accuracy
Smoking and perhaps secondary smoking is associated with many perioperative and postoperative complications, especially respiratory events. Hypoxemia and airway damage can be associated with secondary smoking. The aim of study is to predict the incidence of hypoxemia and airway damage during one lung ventilation for lobectomy.
The clinical diagnosis of sleep apnea is difficult among ESRD patients since the characteristic clinical features of sleep apnea may be absent and since sleep-related symptoms, such as fatigue and sleepiness, may be attributed to kidney failure. However, the evaluation of patients with possible sleep apnea is the same among ESRD patients as in the general population.
High-flow nasal cannula (HFNC) that uses heated and humidified oxygen was recently introduced for bedside care. It has been shown to be associated with reduced risks of tracheal intubation rates and mortality in adult hypoxic patients. The mechanisms of the effects of HFNC are thought to be related to the favorable effects of the heated and humidified gas, the high-flow rate used to minimize the entrainment of room air, and an increase in the ventilation efficiency, including the elimination of nasopharyngeal dead space, positive end-expiratory pressure (PEEP) effects, and improvements in paradoxical abdominal movement. Regarding the effects on lung volume, global ventilation in the lungs increases during HFNC, which is thought to attribute to PEEP effects. However, how regional ventilation is affected during HFNC in comparison with conventional NC remains unknown. Because PEEP in mechanically ventilated patients improves the regional homogeneity of ventilation, investigators postulated that HFNC via PEEP effects would result in more homogeneous regional distributions in the ventilation changes. Investigators therefore assessed global and regional ventilation in patients with hypoxia receiving care via HFNC using electric impedance tomography and compared these results with conventional nasal cannula.