Clinical Research Directory

Hypoxia and Hemodilution Testing in Healthy Adult Volunteers

This study will collect physiological measurements in healthy adult volunteers under controlled hypoxia and hemodilution conditions.

Adaptation of Lung Transplant Recipients at Extreme Altitude

This prospective observational study investigates the effects of intermittent hypoxic conditioning and real high-altitude exposure in lung transplant recipients compared with healthy controls. The study includes an eight-week home-based preparatory phase during which participants use a normobaric hypoxic tent with reduced oxygen concentration. Prior to this phase, all participants receive standardized training on the safe use of the equipment. During the preparatory period, daily vital parameters, including heart rate, oxygen saturation, and heart rate variability, are recorded using a sports watch and a pulse oximeter. Symptoms, adverse events, and subjective well-being are documented daily in an electronic diary. All data are transmitted to the study team via encrypted electronic systems, allowing continuous remote monitoring. At the end of the preparatory phase, participants undergo a clinical evaluation to confirm fitness for the expedition phase. The expedition phase consists of a monitored ascent of Aconcagua (6,971 meters). Before departure, all participants are required to attend a comprehensive safety, protection, and first aid training conducted jointly by the study team and professional expedition providers. The expedition is planned and led by an experienced international expedition company in cooperation with a local provider specializing in high-altitude mountaineering. The expedition includes arrival in Mendoza, preparatory procedures such as equipment checks and permits, followed by a staged ascent to base camp. Subsequent days involve rest periods and acclimatization hikes with the establishment of progressively higher camps. A summit attempt is planned after sufficient acclimatization, followed by descent to high camp. A weather-dependent buffer period is included before the final descent to the valley and return to Mendoza, where the expedition concludes. Total study participation is expected to last approximately 15 weeks, including about eight weeks of home-based preparation and approximately three weeks at altitude. A final follow-up examination is conducted 2 to 4 weeks after completion of the expedition, marking the end of study participation.

Effect of Acute Hypoxia on RIght VEntRicular Function in Healthy Adults.

More and more people are engaging in sports in the mountains, including individuals with heart or lung diseases. At the same time, such diseases are becoming more common in Switzerland. At high altitude, less oxygen is available, which places stress on the body-particularly on the heart, which has to pump blood through the lungs. How the healthy heart, especially the right ventricle, responds to this stress is still not well understood. Therefore, this study investigates how the heart responds to simulated altitudes of 2,500 m and 4,000 m, both at rest and during light physical activity. The present investigation focuses on healthy individuals in order to establish a reference for future comparisons with patients suffering from cardiopulmonary diseases. The primary objective is to assess how right ventricular function changes under conditions of reduced oxygen availability. In addition, vital signs, changes in blood gases, oxygen levels in blood and tissue and shortness of breath are assessed. The "altitude" is simulated using a special gas mixture that participants inhale. Healthy participants undergo three altitude conditions (490, 2,500, and 4,000 m above sea level). The order of the altitude conditions is assigned at random. The aim is to better understand how the right ventricle and other parameters respond to low-oxygen conditions and how affected patients can be better supported in the future.

Structural Modification In Supraglottic Airway Device

The proposed A/Z modification of a supraglottic airway (SGA) incorporates an opening in the SGA body that enables access to the endotracheal tube (ETT) through the body of the SGA without the need of using an exchange catheter, thus enabling an ETT to move in the body of the SGA and convert a supraglottic to endotracheal ventilation. In its original form an adaptor made from same material currently used in the endotracheal tubes can make ventilation through the proposed airway device possible in exactly the same manner of a conventional SGA currently used. This adapter also known as the R-piece can be replaced with an ETT. The modification also allows placement of SGA over an existing ETT to convert and endotracheal (ET) to supraglottic (SG) mode of ventilation without the need to use an exchange catheter.

High-Flow Nasal Cannula for Preventing Hypoxia During Sedated Endoscopy in High-Risk Obstructive Sleep Apnea Patients

Hypoxia represents the most frequent adverse event during propofol-sedated gastrointestinal endoscopy. The STOP-BANG questionnaire serves as a widely adopted, straightforward tool for screening obstructive sleep apnea (OSA) risk, with a score ≥5 identifying high-risk OSA patients who are particularly susceptible to hypoxia under sedation. Although preliminary research from our team suggests that High-Flow Nasal Cannula (HFNC) may lower the incidence of hypoxemia, evidence remains limited and inconsistent in studies specifically targeting high-risk OSA populations. Therefore, this multicenter randomized controlled trial aims to evaluate whether HFNC can effectively reduce the occurrence of hypoxia during sedated gastrointestinal endoscopy in patients identified as high-risk for OSA.

Effect of Acute Hypoxia on RIght VEntRicular Function in Asthma.

More and more people are engaging in sports in the mountains, including individuals with heart or lung diseases. At the same time, such diseases are becoming more common in Switzerland. At high altitude, less oxygen is available, which places stress on the body-particularly on the heart, which has to pump blood through the lungs. How the heart, especially the right ventricle, in people with asthma responds to this stress is still not well understood. Therefore, this study investigates how the heart responds to simulated altitudes of 2,500 m and 4,000 m, both at rest and during light physical activity in patients with asthma. The primary objective is to assess how right ventricular function changes under conditions of reduced oxygen availability. In addition, vital signs, changes in blood gases, oxygen levels in blood and tissue and shortness of breath are assessed. The "altitude" is simulated using a special gas mixture that participants inhale. Participants undergo three altitude conditions (490, 2,500, and 4,000 m above sea level). The order of the altitude conditions is assigned at random. The aim is to better understand how the right ventricle and other parameters respond to low-oxygen conditions and how affected patients can be better supported in the future.

Effect of Acute Hypoxia on RIght VEntRicular Function in HAPE.

More and more people are engaging in sports in the mountains, including individuals with heart or lung diseases. At the same time, such diseases are becoming more common in Switzerland. At high altitude, less oxygen is available, which places stress on the body-particularly on the heart, which has to pump blood through the lungs. How the heart, especially the right ventricle, in people with past HAPE responds to this stress is still not well understood. Therefore, this study investigates how the heart responds to simulated altitudes of 2,500 m and 4,000 m, both at rest and during light physical activity in patients with past HAPE. The primary objective is to assess how right ventricular function changes under conditions of reduced oxygen availability. In addition, vital signs, changes in blood gases, oxygen levels in blood and tissue and shortness of breath are assessed. The "altitude" is simulated using a special gas mixture that participants inhale. Participants undergo three altitude conditions (490, 2,500, and 4,000 m above sea level). The order of the altitude conditions is assigned at random. The aim is to better understand how the right ventricle and other parameters respond to low-oxygen conditions and how affected patients can be better supported in the future.

Pulse Oximeter Accuracy During Stable Hypoxia Plateaus

The aim of this study is to determine the accuracy of devices called pulse oximeters, which measure blood oxygen by shining light through fingers, ears or other skin, without requiring blood sampling. Study will be used with healthy volunteers at rest.

Pharmacologic Induction of Tolerance for Hypoxia & Hypothermia

Warfighter Performance Optimization in Extreme Environments remains an area of important and intense investigation, with the following goals: (1) Optimize, sustain and augment medical readiness and physiological/ psychological performance in extreme and hazardous military operational environments and (2) develop joint DoD countermeasures and guidance to sustain performance, assess physiological status, and reduce injury risk in extreme and hazardous operational environments. Successful and safe outcomes in extreme and hazardous operational environments require that warfighters maintain optimum cognitive and exercise performance during physiologic stress. Extreme environmental conditions encountered in such environments include warfighter exposure to hypoxia and hypothermia, alone or in combination. Both hypoxia and hypothermia undermine O2 delivery system homeostasis, imposing dangerous constraints upon warfighter cognitive and exercise capacity. While red blood cells (RBCs) are commonly recognized as O2 transport agents, their function as a key signaling and control node in O2 system delivery homeostasis is newly appreciated. Through O2 content-responsive modulation of RBC energetics, biomechanics, O2 affinity and control of vasoactive effectors in plasma - RBCs coordinate stabilizing responses of the lung, heart, vascular tree and autonomic nervous system - in a fashion that maintains O2 delivery system homeostasis in the setting of either reduced O2 availability (hypobaric hypoxia) or increased O2 demand (hypothermia). Human RBCs demonstrate adaptive responses to exercise, hypoxia and hypothermia - these changes are commonly appreciated as a key element enabling high altitude adaptation. However, under conditions of hypoxia and hypothermia, without prior adaptation, RBC performance is adversely impacted and limits the dynamic range of stress adaptation for O2 delivery homeostasis - therefore limiting warfighter exercise capacity and cognitive performance in extreme environments, such as during acute mountain sickness.

The Efficacy and Safety of the Supraglottic Oxygenation Via Nasotracheal Intubation for Deep Sedation Fiberoptic Bronchoscopy

Bronchoscopy is now widely used for the diagnosis and treatment of various respiratory diseases. However, the procedure is highly stimulating and provokes a strong stress response; because the airway is shared, patients are prone to hypoxia. With the growing emphasis on comfortable care, demand for anesthesia during bronchoscopy has increased. Deep sedation is the most common approach, but when administered in the supine position it often causes the tongue base to fall back. Both nasopharyngeal and oropharyngeal airways can relieve this obstruction, yet neither connects seamlessly to an oxygen supply line, resulting in insufficient oxygen delivery.We therefore replaced the nasopharyngeal airway with a wired endotracheal tube (size 4.0 or 4.5) inserted via the nose. This thinner tube couples easily to an oxygen line or ventilator circuit, partially relieves airway obstruction, and allows ample supraglottic oxygenation. The present study was designed to evaluate the feasibility and safety of this modified oxygen-delivery method in patients undergoing deep sedation for bronchoscopy.

Hypoxia and Heart Rate Variability

The purpose of this study is to evaluate how variations in oxygen demands may change heart electrical activity in individuals with and without oxygen dependence.

Graded Exercise Hypoxia Testing

The purpose of this study is to develop a single, standardized test to determine how individuals tolerate acute hypoxia in a stepwise fashion. We aim to evaluate the association between multiple factors, such as ventilatory compensation, heart rate response, acid-base changes, sex, pulmonary function, etc, which may explain why some individuals tolerate exercise in hypoxia better than others. Identifying these factors of association will inform future pharmacological and non-pharmacological attempts to combat acute hypoxic exercise.

The Efficacy of Remimazolam on Incidence of Hypoxia During Sedated Transvaginal Oocyte Retrieval: A Multicenter Randomized Controlled Trial.

Hypoxia is the most common adverse reaction during sedation outside the operating room.Exploring novel drug combinations to reduce the incidence of hypoxia during sedation in patients undergoing transvaginal oocyte retrieval procedures enhances patient safety and lowers perioperative adverse event rates. This multicenter, prospective, randomized, controlled clinical study will compare the hypoxia incidence rate of the remimazolam-alfentanil combination against the commonly used propofol-alfentanil combination.

Endotracheal Tube Suctioning Versus No Suctioning During Emergence From General Anesthesia

The goal of this study is to determine whether omitting tracheal suctioning immediately prior to extubation is non-inferior to routine tracheal suctioning with respect to early postoperative oxygenation among adult surgical patients (aged 18-90 years, American Society of Anesthesiologists \[ASA\] physical status I-III) undergoing elective surgery under general anesthesia with endotracheal intubation. The study addresses the following questions: * Primary outcome (non-inferiority): * Is the risk of postoperative desaturation (oxygen saturation \[SpO₂\] \<92% within 60 minutes after extubation) in the no-suction group not worse than in the routine-suction group by more than 10 percentage points? * Secondary outcomes (superiority): * Does omitting tracheal suctioning reduce postoperative cough severity and sore throat? * Does omitting tracheal suctioning avoid increasing extubation-related adverse events? Participants will be randomly assigned (1:1) to one of two groups: * Routine suctioning (SUC): Endotracheal suctioning plus oropharyngeal suctioning immediately before extubation * No suctioning (NON-SUC): Oropharyngeal suctioning only, without endotracheal suctioning All participants will receive standard anesthetic care and postoperative monitoring in the post-anesthesia care unit (PACU) for 60 minutes. Follow-up for airway symptoms and patient satisfaction will be conducted at 24 hours after surgery.

Optimizing Care in Critically Ill at UCHealth by Liberalizing the Target O2 in Mechanically-ventilated ICU Patients

A multimodal educational intervention to target an oxygen saturation target range (SpO2 90-96%) will reduce ventilator length of stay and reduce occult hypoxemia by increased awareness and adherence to a designated oxygen saturation target range.

Going to Altitude With Anxious-depressive Symptoms

Introduction: Currently, there is a lack of international guidelines or clinical recommendations for individuals with mental illnesses (i.e., bipolar disorder, posttraumatic stress disorder) going on high altitude sojourns. However, these guidelines would be important considering that mental illnesses are among the most common disorders worldwide and millions of people are hiking at high altitudes in the Alps, being granted easy access up to 3800m by cable cars. Before conceptualizing these guidelines, it seems necessary to study the physiological and psychological effects of ambient pressure changes leading to oxygen deficiency (hypoxia) in individuals with mental illnesses when being exposed to hypoxic conditions. The investigators hypothesize a shift towards negative affective responses and state anxiety as well as increased levels of neurotransmitter precursor amino acids (PHE/TYR and KYN/TRP) in individuals with mental illnesses when being exposed to hypoxic conditions. Methods and Analysis: The investigators plan to perform a double-blind randomized controlled trial in a safe laboratory environment by using a normobaric hypoxic chamber. Participants suffering from depression and anxiety symptoms will be included as well as age and sex-matched healthy controls. They will attend a six-hour exposure equivalent to 3800m of altitude as well as a six-hour exposure to sham hypoxic conditions. Recruited participants will be screened by the Beck Anxiety and Depression Inventory, the Symptom Checklist (SCL-90) as well as an interview assessment. Affective responses in state anxiety will be assessed before, and during each hour of exposure by using the Feeling Scale (FS), Felt Arousal Scale (FAS), Positive and Negative Affect Schedule (PANAS), State-Anxiety Inventory (STAI) and subjective mental stress levels (Visual Analogue Scale; VAS). Physiological parameters will be assessed by venous blood sampling, pulse oximetry and oxidative stress level measurement before entering the chamber, after three and six hours of exposure. Additionally, symptoms of acute mountain sickness will be assessed by the Lake Louise Score before, after three and six hours of exposure. Follow-up measurements are planned one and seven days after the chamber visit, consisting of venous blood sampling, the Beck Anxiety and Depression Inventory. A series of univariate analyses of covariance (ANCOVA) for repeated measures will be used to test the three-way (i.e. "group × condition × time") and two-way ("group × condition" and "group × time") interactions. Analyses will be adjusted for possible confounding, by adding age, sex, smoking, prior AMS, and medication status in the models as covariates. Ethics and dissemination: Ethical approval has been obtained from the ethics committee of the Medical University of Innsbruck (1250/2021).

Outpatient Pediatric Pulse Oximeters in Africa

The primary objective of this clinical trial is to evaluate the performance of three pulse oximeters during outpatient care within Cape Town, South Africa. This objective will be achieved through generating evidence on how, why, for whom, to what extent and at what cost can paediatric pulse oximetry devices improve the management of hypoxemic children. This will be done with two inter-linked studies: * Aim 1: Determine the impact of two novel paediatric pulse oximeter devices on the correct management of hypoxaemia. * Aim 2: Describe the burden of hypoxaemia and risks for mortality amongst children presenting with acute respiratory infections in a low-resource setting in Cape Town.

Determination of SpO2 and PR Accuracy Specifications at Rest (71Ag_Vital-0031)

The aim of this study is to determine the accuracy of devices called pulse oximeters, which measure blood oxygen by shining light through fingers, ears or other skin, without requiring blood sampling. Study will be used with patients at rest

Effect of Different Positions During Extubation on Incidence of Hypoxemia in the Peri Extubation Period

Pediatric Obstructive Sleep Apnea Syndrome (OSAS) is common, often due to enlarged tonsils/adenoids. Tonsillectomy/adenoidectomy frequently performed under GA with tracheal intubation due to the age of children. Risk of hypoxemia and respiratory complications during the peri-extubation period is high.

Effects of Breathing Training and Nitrate on Exercise at Simulated Altitude

This study investigates whether respiratory muscle training (RMT) and dietary nitrate supplementation can improve exercise tolerance under simulated moderate altitude conditions. Exposure to reduced oxygen availability at altitude places additional strain on the cardiovascular and respiratory systems, which may limit endurance performance. By combining RMT-designed to strengthen the muscles involved in breathing-with nitrate therapy, which enhances nitric oxide availability and vascular function, this study aims to determine whether these interventions independently or synergistically improve oxygen delivery, reduce physiological strain, and enhance exercise performance. The findings will help identify non-pharmacological strategies to improve physical performance and tolerance to hypoxia in both clinical and operational environments.

COMBO Endoscopy Oropharyngeal Airway Reduces Hypoxia During Sedated Gastrointestinal Endoscopy in Obese Patients: A Multicenter, Randomized, Controlled Clinical Trial

Hypoxia represents the prevailing adverse occurrence during the sedation of patients undergoing gastrointestinal endoscopy with propofol. This is particularly true for obese patients, who have a higher incidence of hypoxia. A recent innovation in this domain is the COMBO Endoscopy Oropharyngeal Airway-a multifaceted device that encompasses capnography monitoring, bite block , oxygenation support, and oropharyngeal airway management. This device has been purposefully designed to cater to the unique requirements of endoscopic procedures. The principal objective of this study is to assess the efficacy and safety of the COMBO Endoscopy Oropharyngeal Airway in reducing the incidence of hypoxia in obese patients undergoing gastrointestinal endoscopy under sedation.

Impact of Early Aging and Menopause on the Vascular Responses to Hypoxia

The purpose of this study is to examine hypoxic vasodilation and the role of beta-adrenergic receptors in younger premenopausal, perimenopausal, and older postmenopausal women.

HFNC Compared With Facial Mask in Patients With Chest Trauma Patients

Guidelines for noninvasive ventilation (NIV) recommend continuous positive airway pressure in patients with thoracic trauma who remain hypoxic . However, no any suggestion was applied for high flow nasal cannula (HFNC). Therefore, Our aim was to determine whether HFNC reduces intubation in severe trauma-related hypoxemia.

Pulse Oximeter Accuracy in Healthy Humans During Hypoxia

The aim of this project is to test the accuracy of pulse oximeters during mild, moderate and severe hypoxia. This is done by comparing the reading of the pulse oximeter during brief, steady state hypoxia with a gold-standard measurement of blood oxygen. This study will be done on healthy male or females between the age group of 18-50.