Active clinical trials for "Hypercapnia"

This study will evaluate magnetic resonance imaging (MRI ) methods for measuring changes in the brain's blood flow during hypercapnia (a condition of excess carbon dioxide in the blood). MRI is a diagnostic tool that uses a large magnet and radio waves to produce images of the body without X-rays. Healthy normal volunteers in this study may have as many as six MRI scans over a 2-year period. For this procedure, the person lies on a stretcher placed in a strong magnetic field produced by the MRI machine. During the scan, the person's blood carbon dioxide (CO2 ) levels will be increased either by: 1) breathing air mixtures containing up to 5% CO2; or 2) receiving an intravenous (I.V.) injection of a drug called acetazolamide. Persons who breathe CO2 will have their heart rate, blood pressure and oxygen levels monitored throughout the procedure. Those receiving acetazolamide will have the drug injected intravenously (I.V.) into an arm vein. If the volunteer experiences any unpleasant side effects from the CO2 or acetazolamide, the study will be stopped. The information gained from this study will be used to develop better ways to study brain function, possibly leading to better diagnostic and treatment methods.

Assessment of Spry Health's Loop oximetry accuracy in profound hypoxia Assessment of Spry Health's Respiratory rate accuracy in normal conditions and profound hypoxia

Baseline cerebral blood flow through the middle cerebral artery (MCA) and cerebral vasodilator response of the MCA to inhaled carbon dioxide (CO2) will be measured in young women, young men, older women, and older men using Magnetic Resonance (MR) imaging and transcranial Doppler ultrasound (TCD). Data collection techniques will be compared.

The proposed study will measure the time from the end of surgery until the time patients meet the discharge criteria from the postoperative anesthesia care unit and the time from the end of surgery until the patients regained cognitive function after anesthesia.

High flow nasal therapy (HFNT) has not been well evaluated for treating hypercapnia The purpose of this study is to determine whether high flow nasal therapy (HFNT) can decrease hypercapnia and improve respiratory distress parameters in Emergency Department patients with acute hypercapnic respiratory failure related to cardiogenic pulmonary edema and to compare its efficacy to that of non invasive ventilation.

Noninvasive ventilation (NIV) is essential to treat acute hypercapnic respiratory failure. However, facial pressure ulcers appearing during facemask-delivered noninvasive ventilation are a source of NIV failure by interface intolerance. A Philips facemask (model : AF541 SE Oro-Nasal mask) has the particularity to display two options for its positioning : a usually used "over-the-nose" positioning or an "under-the-nose" positioning that is supposed to reduce the incidence of facial pressure ulcers while keeping in the same time the qualities of a standard facemask. The goal of this controlled randomized trial is to test the hypothesis that the "under-the-nose" positioning actually reduces the incidence of facial pressure ulcers, compared to the usually used "over-the-nose" positioning. Results of this trial should lead to the proposition of a new interface strategy to prevent facial pressure ulcers and therefore to improve the tolerance of NIV via the use of facemasks displaying an "under-the-nose" positioning.

Hypercapnia is a frequent clinical situation defined as an elevation of the partial pressure of carbon dioxide (PaCO2) above 45 mmHg. Several physiopathological parameters such as respiratory minute volume, dead space volume or CO2 production influence the PaCO2. Therefore, hypercapnia can affect the time of various diseases. Available epidemiological data regarding hypercapnia are from studies investigating the efficacy of non-invasive ventilation (NIV), with different population cohorts. However, their interpretation must be cautious given the heterogeneity in patient case-mix and results. Then, whether hypercapnia is a common reason for intensive care unit (ICU) admission, epidemiological data is scarce and heterogeneous. The aim of this study is to investigate the epidemiological, clinical determinants and outcomes of patients admitted to ICU with hypercapnic respiratory failure.

Patients with Motor Neurone Disease (MND) admitted to Lane Fox Unit /Royal Brompton Hospital and/or reviewed in Lane Fox Unit /Royal Brompton Hospital clinics and/or outreach review will be approached for participation in the study Physiological assessment and measurement of arterial stiffness will be performed in all patients at baseline and after the use of non invasive ventilation for 6 weeks. MND patients not requiring mechanical ventilation will serve as controls since non invasive ventilation cannot be withheld from MND patients in type II respiratory failure. Data will be analysed to look for differences between groups, relationships in baseline or change from baseline in respiratory physiological measures, inflammatory indices, breathlessness, and arterial stiffness. Age, Height, Weight History and Physical Examination Evaluation of dysponea: mMRC, Borg Scale (Seated-Supine) Amyotrophic lateral sclerosis functional rating scale (ALSFRS-R) Sleep Disordered Breathing in Neuromuscular Disease Questionnaire (SiNQ-5) 24 hour blood pressure monitor Carotid-femoral pulse wave velocity Respiratory Muscle Strength - Maximal Inspiratory Pressure, Maximal Expiratory Pressure, and Sniff Nasal Inspiratory Pressure Spirometry - FEV1 and FVC Arterial Blood Gas CRP and fibrinogen (clinically) Breathe CO exhale

Opioids are an effective instrument for patients with acute and chronic pain. Their route of administration ranges from transdermal to subcutaneous application through to Intravenous Patient-Controlled Analgesia (IV-PCA). The use of IV-PCA-pumps has considerable advantages including decreased delay in the administration of opioids from the time requested, individual dose intervals, self -control of their therapy, rapidity and ease of dose titration . These potential benefits, however are balanced by the need for careful assessment of adverse effects, including decreased quality of life because of the patient's sedation, constipation and possible episodes of bradypnoea and desaturation, eventually leading to respiratory depression (RD) requiring treatment. Often described safety features that help prevent overdosing are PCA bolus dose, delay, and lockout interval. Even though the risk of serious, potentially life threatening complications by using IV-PCA without a background infusion was described to be very low (0.24%) compared to other methods of opioid delivery , adverse effects like worrying degrees of hypoxemia and bradypnoea do occur and often remain undetected due to the lack of continuous monitoring. One of the possible causes of patient harm are medication errors associated with PCA administration, a common form of PCA errors, which is a significant source of preventable patient morbidity and hospital resource utilization. The individual patient response to a particular dose of opioids depends on diagnosed or unrecognized comorbidities. Clinical experience has shown that it is not possible to prospectively identify all patients who may be at increased risk. Conventional opioid monitoring protocol may fail to detect frequent episodes of bradypnoea and desaturation measured by the respiratory rate (RR) and Saturation of Peripheral Oxygen (SpO2) because even at a low respiratory rate SpO2 is usually maintained, so that pulse oxymetry might fail to detect respiratory deterioration, particularly if a patient is receiving supplemental oxygen. Therefore, continuous monitoring could be considered more sensitive, especially if it contains the measurement of Partial Pressure of Carbon dioxide (PCO2), which is a good parameter for monitoring ventilatory function. The 'gold standard' method to measure the arterial partial pressure of carbon dioxide (PaCO2) is still the arterial blood gas analysis. But arterial sampling including catheterization or intermittent arterial puncture is invasive and expensive and associated with pain and discomfort for the patient. Therefore cutaneous carbon dioxide tension (PcCO2) measurement was suggested to be used as a non-invasive surrogate measure of PaCO2. SpO2, and tcPCO2, are important clinical parameters that should be used in conjunction with each other. SpO2 reflects oxygenation, while tcPCO2 reflects ventilation; the first can still be normal while the second may herald early changes in respiratory status. Capnography may provide the earliest indication of opioid-induced respiratory depression. It is important to monitor changes from a baseline tcPCO2 level. As the tcPCO2 level starts to increase, early intervention and changes in medication can be made. The present study aims to examine combined oxymetry and transcutaneous capnography using a single earlobe sensor (V-Sign™, Sentec AG, Therwil, Switzerland) in chronic pain patients treated with opioids where non-invasive monitoring of ventilation is needed because ventilatory disturbances are suspected. This may, potentially, improve patient's quality of life.

This study will use magnetic resonance imaging (MRI) to examine the role of prostaglandins-a type of fatty acid with hormone-like actions-in the regulation of brain blood flow. The results will provide information on how to better use this technique to study brain function, which, in turn, may lead to a better understanding of certain illnesses and more effective treatments. Healthy normal volunteers 18 years of age and older may be eligible for this study. Participants will fill out a health questionnaire and undergo a history, physical examination and MRI studies. MRI is a diagnostic tool that uses a strong magnetic field and radio waves instead of X-rays to show structural and chemical changes in tissues. During the scanning, the subject lies on a table in a narrow cylinder containing a magnetic field. An intercom system allows the subject to speak with the staff member performing the study at all times during the procedure. Four separate studies will be done-two carbon dioxide inhalation studies and two functional activation studies-as follows: Carbon dioxide inhalation (indomethacin): This study is done in two parts. In both parts, an MRI brain scan is done. During the scan, the subject inhales an air mixture containing 6% carbon dioxide through a facemask or mouthpiece. Blood pressure and heart rate are monitored during inhalation of the mixture. For the second part of the study, indomethacin-a non-steroidal anti-inflammatory drug-is injected through a catheter (thin flexible tube) in an arm vein. Indomethacin inhibits prostaglandin production. Total scan time averages between 45 and 90 minutes, with a maximum of 2 hours. Carbon dioxide inhalation (rofecoxib and celecoxib): This study is identical to the one above, except either rofecoxib or celecoxib is given instead of indomethacin. Both of these drugs are also non-steroidal anti-inflammatory drugs that inhibit prostaglandin production. Unlike indomethacin, rofecoxib and celecoxib are given orally instead of through a vein, so, to allow time for the drug to be absorbed, the second scan is delayed for 2 hours. Functional activation (indomethacin): This study is done in two parts. In both parts, a MRI brain scan is done. During the study, the subject performs a simple motor task, such as finger tapping. For the second part of the study, indomethacin is injected through a catheter in an arm vein. Functional activation (rofecoxib and celecoxib): This study is identical to the indomethacin functional activation study, except either rofecoxib or celecoxib is given instead of indomethacin. Because they are given orally instead of through a vein, the second scan is delayed 2 hours to allow time for the drug to be absorbed.