Clinical Research Directory

Effect of Hydrogen Gas on Hyperbaric Oxygen Toxicity

The goal of this trial is to investigate whether adding a small fraction of hydrogen gas to an oxygen-enriched breathing mixture can reduce pulmonary oxygen toxicity (POT) in healthy and active divers from the Swedish Armed Forces. The main questions it aims to answer are: * Does hydrogen gas reduce oxidative stress and changes in pulmonary function associated with prolonged hyperbaric oxygen exposure? * What are the underlying pathophysiological mechanisms of pulmonary oxygen toxicity? Researchers will compare oxygen-enriched breathing gas with 1-2% hydrogen to oxygen-enriched gas with 1-2% nitrogen (control) to see if hydrogen provides protective effects against POT during hyperbaric exposure. Participants will: * Complete two hyperbaric exposure sessions (hydrogen vs. nitrogen), each lasting 240 minutes at 1.75 ATA * Undergo pulmonary function tests and sampling of blod and urin before and after each session * Serve as their own controls in a double-blind, randomized, crossover study design

Oxygen Toxicity: Mechanisms in Humans

The goal of this clinical trial is to learn about the mechanisms of oxygen toxicity in scuba divers. The main questions it aims to answer are: * How does the training of respiratory muscles affect oxygen toxicity? * How do environmental factors, such as sleep deprivation, the ingestion of commonly utilized medications, and chronic exposure to carbon dioxide, impact the risk of oxygen toxicity? * How does immersion in water affect the development of oxygen toxicity? Participants will be asked to do the following: * Undergo a basic screening exam composed of health history, vital signs, and some respiratory function tests * Train their respiratory muscles at regular intervals * Exercise on a cycle ergometer both in dry conditions and underwater/under pressure in the context of medication, sleep deprivation, or carbon dioxide exposure Researchers will compare the performance of each subject before and after the possible interventions described above to see if there are changes in exercise performance, respiratory function, cerebral blood flow, and levels of gene expression.

Influence of FreeO2 on Percentage of Time Within Oxygen Saturation Target Using Noninvasive Ventilation (NIV) and Continuous Positive Airway Pressure (CPAP) for Patients Admitted for AECOPD or Bariatric Surgery

The main objective is to evaluate the FreeO2 device combined with noninvasive respiratory support technique for COPD patients and postoperative bariatric surgery patients. The main hypothesis is that FreeO2 device for oxygen therapy associated with NIV or nasal high flow oxygen therapy (NHFOT) allows to reach better oxygenation and avoid hypoxemia and hyperoxia.

Comparison of Two Oxygenation Targets With Two Different Oximeters - Impact on Oxygen Flow Rates and Oxygenation

The investigators recently evaluated 4 different oximeters among the most commonly used with arterial catheter in place and compared SpO2 with SaO2 obtained on arterial gas. Correlations between SaO2 and SpO2 were poor for all oximeters, as previously known, and SpO2-SaO2 bias were different between oximeters. Some oximeters (Masimo, Nellcor) had lower biases but they detected less well hypoxemia. Some oximeters underestimated SaO2 (Nonin) but detected very well hypoxemia, and some overestimated SaO2 (Philips). The investigators concluded that oximeters provide different informations to clinicians, and oxygenation targets should take into account for these differences. The assumption is that the SpO2 target AND oximeter used will both have an impact on oxygen flows and that these effects will add up. With a high SpO2 target, oxygen flows will be significantly greater and with the Nonin oximeter, the required flows will be greater than with the Philips oximeter. NB: the results obtained were in a population with light skin pigmentation (96% of the patients were Fitzpatrick 1-2, reflecting the local hospitalized population).

Comparison of Several Oxygenation Targets With Different Oxygen Interfaces - Impact on Oxygen Flow Rates

Oxygen therapy is at the heart of the healthcare system. Oxygen flow rates depend on a number of confounding factors confounding factors (target used, skin pigmentation, pulse oximeter used, etc.) The investigators have recently have recently demonstrated that the combination of these factors (different peripheral oxygen saturation (SpO2) targets and different oximeters) can have a significant impact on oxygen flows rates. The effect on oxygen flow was not simply additive . The aim of this study is to evaluate the impact of the interface used on oxygen flow rates in different patient populations (main objective). The investigatoers also evaluate the impact of the interface on carbon dioxide (PaCO2), in particular with closed oxygen masks, with which rebreathing is theoretically possible (secondary objective). secondary objective).

Epidemiological Assessment of Technical Diving Accidents in Mainland France and Factors Predictive of Severity (TEKCare)

This retrospective study aims at an epidemiological description of the clinical presentation of medical problems in technical diving. It assess anthropometric data, diving experience and dive planification, clinical presentation, treatment received and pronostic to understand specificity of this community.

Lung Ultrasound Guided Choice of Best Positive End-Expiratory Pressure in Neonatal Anesthesia

The goal of this RCT is to demonstrate that, in neonatal anesthesia, the use of Lung Ultrasound (LUS) to guide choice of best Positive End-Expiratory Pressure (Peep) - the one that efficiently avoids lung atelectasis - leads to better gas exchange in the lung thus can lead to reduction of FiO2 applied to ventilatory setting in order to achieve same peripheral saturations of oxygen (SpO2). Specific aims of the study are: 1. to determine if LUS-guided PEEP choice in neonatal anesthesia, compared to standard PEEP choice, can lead to reduction of FiO2 applied to the ventilatory setting in order to maintain same SpO2s. 2. to determine if patients treated with LUS-guided PEEP will develop less postoperative pulmonary complications in the first 24 hours. 3. to compare static respiratory system compliance between groups. 4. to determine if there is a significant difference in hemodynamic parameters and amount of fluids infused or need for vasopressors between the two groups.