Carbon Dioxide Breathing for Orthostatic Hypotension
Recruiting in Palo Alto (17 mi)
Overseen bySatish R Raj, MD
Age: 18+
Sex: Any
Travel: May Be Covered
Time Reimbursement: Varies
Trial Phase: Academic
Recruiting
Sponsor: University of Calgary
Must not be taking: Autonomic drugs
Disqualifiers: Somatization, Severe anxiety, Pregnancy, others
No Placebo Group
Trial Summary
What is the purpose of this trial?The Autonomic (or "automatic") Nervous System (ANS) regulates internal processes, including control of heart rate and blood pressure (BP). When someone stands, and gravity tries to pull blood away from the brain, the ANS works to maintain BP and brain blood flow. Neurogenic Orthostatic Hypotension (NOH) occurs when our "fight-or-flight" part ("sympathetic") of the ANS fails. BP can drop a lot when upright, reducing blood flow and oxygen delivery to the brain, and this can cause symptoms of light-headedness, nausea, and fainting.
One solution to help counter the effects of NOH may be to increase sympathetic activity by breathing higher levels of carbon dioxide. In healthy volunteers, small increases in the amount of inhaled carbon dioxide has been shown to increase BP in the upright position, and this improves symptoms!
The objectives of the current study are to apply carbon dioxide in patients with NOH and healthy controls to: (a) evaluate the effects of breathing carbon dioxide on BP and brain blood flow, and (b) determine if a device that increases carbon dioxide while standing will work as a new therapy
Will I have to stop taking my current medications?
The trial excludes participants taking medications that could interfere with autonomic function testing, so you may need to stop certain medications. It's best to discuss your specific medications with the trial team to see if they are allowed.
Is carbon dioxide therapy safe for humans?
The research does not provide specific safety data on carbon dioxide therapy, but it highlights that excessive oxygen therapy can be harmful, especially for patients with conditions like COPD, which may involve carbon dioxide retention.
12345How does the treatment Sequential Gas Delivery for orthostatic hypotension differ from other treatments?
Sequential Gas Delivery, also known as Carbon Dioxide Therapy, is unique because it involves controlled breathing of carbon dioxide to manage orthostatic hypotension, which is different from traditional treatments that may not focus on gas delivery. This approach is novel as it uses the therapeutic effects of carbon dioxide, which is not a standard treatment for this condition.
36789Eligibility Criteria
This trial is for adults over 18 who can consent, travel to the University of Calgary, and are non-smokers. It's not for those with dementia, substance abuse issues, severe organ diseases, pregnant or breastfeeding women, people on certain medications affecting autonomic function or unable to wear a mask.Inclusion Criteria
Able and willing to provide informed consent
I am 18 years old or older.
I am either male or female.
+2 more
Exclusion Criteria
You have severe anxiety or somatization symptoms.
Other factors which in the investigator's opinion would prevent the participant from completing the protocol, including poor compliance during previous studies
I need portable oxygen for breathing, either at rest or during physical activity.
+5 more
Trial Timeline
Screening
Participants are screened for eligibility to participate in the trial
2-4 weeks
Treatment
Participants undergo Active Stand Tests with varying levels of CO2 and O2 to evaluate the effects on blood pressure and orthostatic tolerance
5 sessions
5 visits (in-person)
Follow-up
Participants are monitored for safety and effectiveness after treatment
4 weeks
Participant Groups
The study tests if breathing in higher levels of carbon dioxide (Sequential Gas Delivery) can help manage low blood pressure when standing in patients with Neurogenic Orthostatic Hypotension by increasing blood pressure and brain blood flow.
5Treatment groups
Experimental Treatment
Active Control
Group I: +5mmHg CO2Experimental Treatment1 Intervention
All participants will complete an active stand breathing +5mmHg of CO2 relative to baseline
Group II: +10mmHg CO2 + 50mmHg O2Experimental Treatment1 Intervention
All participants will complete an active stand breathing +10mmHg of CO2 relative to baseline and 50mmHg of O2
Group III: +10mmHgExperimental Treatment1 Intervention
All participants will complete an active stand breathing +10mmHg of CO2 relative to baseline
Group IV: +0mmHg CO2 Clamped at baselineExperimental Treatment1 Intervention
All participants will complete an active stand with their CO2 held constant at baseline
Group V: Room AirActive Control1 Intervention
All participants will complete an active stand breathing room air with CO2 free to fluctuate
Find a Clinic Near You
Research Locations NearbySelect from list below to view details:
University of CalgaryCalgary, Canada
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Who Is Running the Clinical Trial?
University of CalgaryLead Sponsor
References
Oxygen Use in Critical Illness. [2020]Oxygen is the most commonly used drug in critical care. However, because it is a gas, most clinicians and most patients do not regard it as a drug. For this reason, the use of medical oxygen over the past century has been driven by custom, practice, and "precautionary principles" rather than by scientific principles. Oxygen is a life-saving drug for patients with severe hypoxemia, but, as with all other drugs, too much can be harmful. It has been known for many decades that the administration of supplemental oxygen is hazardous for some patients with COPD and other patients who are vulnerable to retention of carbon dioxide (ie, hypercapnia). It has been recognized more recently that excessive oxygen therapy is associated with significantly increased mortality in critically ill patients, even in the absence of risk factors for hypercapnia. This paper provides a critical overview of past and present oxygen use for critically ill patients and will provide guidance for safer oxygen use in the future.
Administration of oxygen therapy. [2008]This article aims to increase nurses' knowledge of the safe administration of oxygen therapy in acute care. The administration and potential complications associated with delivery of oxygen to patients with chronic obstructive pulmonary disease (COPD) and type II respiratory failure are discussed.
Intermittent short-term negative pressure ventilation and increased oxygenation in COPD patients with severe hypercapnic respiratory failure. [2019]With the aim of testing a method that allows increasing concentrations of oxygen to be administered to patients with severe hypoxemia and hypercapnia while avoiding the risk of increasing respiratory acidosis, we studied 17 male patients with advanced chronic obstructive pulmonary disease (COPD) and severe hypercapnic respiratory failure. During 6 h and on one day only, all patients were given intermittent negative pressure ventilation (INPV) together with oxygenation starting at a concentration of 24 percent and increasing to 30 percent. Using this procedure, it was possible to raise arterial PaO2 to safe levels (from 47.2 +/- 3 mm Hg to 61.5 +/- 6 mm Hg, p less than 0.001) without increasing hypercapnia, and a significant drop in PaCO2 levels (from 74.4 +/- 9 mm Hg to 65.6 +/- 12 mm Hg, p less than 0.005) was even observed. One hour after INPV ended, the mean values of PaO2, PaCO2, oxygen saturation, and pH were also significantly better than prestudy values. We conclude that INPV and oxygen therapy with increasing oxygen flow could constitute an alternative option to intubation and mechanical ventilation in cases of severe hypercapnic respiratory failure due to advanced COPD.
Implementing target range oxygen in critical care: A quality improvement pilot study. [2022]Iatrogenic hyperoxaemia is common on critical care units and has been associated with increased mortality. We commenced a quality improvement pilot study to analyse the views and practice of critical care staff regarding oxygen therapy and to change practice to ensure that all patients have a prescribed target oxygen saturation range.
Oxygen therapy and oxygen toxicity. [2022]When oxygen therapy is warranted, the minimum effective dose generally should be given. Hypoxemic patients who have normal baseline ABG may be treated initially with an intermediate to high FiO2 in the range of 35% to 100%, depending on the severity of the respiratory distress. The majority of patients with exacerbations of COPD who are not in extremis may be given an initial FiO2 of 28%, especially if their previous response to oxygen is known. When treating patients who have chronic severe hypercapnia (eg, those requiring chronic home oxygen), the initial FiO2 should be 24% even though renal compensation of the respiratory acidosis has occurred. Further mild elevation of the PaCO2, due mainly to the V/Q mismatch that oxygen therapy induces, may be sufficient to precipitate unacceptable hypercapnia. Patients with exacerbations of COPD who are obviously in extremis, with severe hypoxemia and acidosis, should start with an FiO2 of 24% unless they are being mechanically ventilated. The severity of the hypoxemia and acidosis is more predictive for the development of CO2 narcosis and respiratory failure than is the degree of hypercapnia in these patients. The FiO2 can be increased to 28% and incrementally higher if low FiO2 is tolerated. The use of a high FiO2 is subject to the following guidelines for prevention of clinically significant oxygen toxicity: 100% oxygen at atmospheric pressure is safe if given for less than six hours; 70% oxygen is probably safe for 24 hours; and after this time, 45% should be the approximate upper limit to the FiO2.(ABSTRACT TRUNCATED AT 250 WORDS)
[Ambulatory long-term oxygen therapy]. [2016]Administration of oxygen is an accepted component of the treatment of acute diseases leading to temporary arterial hypoxemia. In addition, long-term oxygen therapy of patients with chronic hypoxemia secondary to chronic obstructive lung disease (COPD) has become increasingly common, after beneficial effects on quality of life and survival have been reported. This form of treatment, however, is costly, rather complex and demanding. Therefore, strict criteria have to be considered in the selection of hypoxemic patients with COPD. This article reviews the tests and criteria required for the prescription of long-term oxygen therapy as well as newer technical aspects in its application with special emphasis on transtracheal catheters.
Effect of oxygen administration during sleep on skin surface oxygen and carbon dioxide tensions in patients with chronic lung disease. [2013]Hypoxemia, hypercarbia, and cor pulmonale ultimately occur in most patients with chronic lung disease. Although oxygen therapy may reduce or delay the development of pulmonary hypertension and myocardial failure in these patients, its use is thought to lead to CO2 narcosis and apnea. The effect of O2 administration during sleep has been examined in 12 patients (seven with cystic fibrosis, three with bronchopulmonary dysplasia, one with bronchiolitis obliterans, and one with severe hypersensitivity pneumonitis) using skin surface O2 (Roche) and CO2 (Radiometer) electrodes. Both electrodes were calibrated over wet gas and applied at 44 C. Ten patients had chronic hypercarbia (PaCO2 62 +/- 19 torr; range 46 to 103 torr) when awake. Humidified oxygen was administered by nasal cannula, Venturi mask, or head hood. Oxygen flow was increased every 20 minutes from 80 minutes or until the patient awoke. In eight of ten patients with hypercarbia and in the two normocarbic patients, skin surface carbon dioxide tension (PsCO2) increased by 10% or less as the skin surface oxygen tension (PsO2) was increased. In the remaining two patients with hypercarbia (both had cystic fibrosis) PsCO2 increased 18% and 24% as PsO2 was increased. These last two patients with depressed responsiveness to CO2 could not be separated from the other patients by clinical or laboratory criteria. It is concluded that the skin surface blood gas tensions are a simple and reproducible method for adjusting oxygen therapy in patients with chronic lung disease, and although the response to oxygen varies from patient to patient, most patients with chronic hypercarbia retain their central responsiveness to CO2 during sleep and for them O2 therapy is probably safe.
Altitude mountain sickness among tourist populations: a review and pathophysiology supporting management with hyperbaric oxygen. [2011]In the mountain climbing community, conventional prevention of altitude mountain sickness (AMS) relies primarily on a formal acclimatization period. AMS symptoms during mountaineering climbs are managed with medication, oxygen and minor recompression (1524-2438 m altitude) using a portable chamber, such as the Gamow Bag. This is not always an acceptable therapy alternative in a predominantly elderly tourist population. The primary problem with reduced pressure at high altitude is hypoxaemia, which causes increased sympathetic activity, induces pulmonary venous constriction, while increasing pulmonary blood flow and regional perfusion. Rapid assents to altitude contribute to an increased incidence of decompression sickness (DCS). The treatment of choice for DCS is hyperbaric oxygenation, thus, treatment of high-altitude induced hypoxaemia using hyperbaric oxygenation (HBO(2)) is logical. Life Support Technologies group and the Center for Investigation of Altitude Medicine (CIMA, in Cusco, Peru) propose a comprehensive and multidisciplinary approach to AMS management. This approach encompasses traditional and advanced medical interventions including the use of a clinical HBO(2) chamber capable of recompression to three times greater than sea level pressure (3 atmosphere absolute (ATA)). The system uses a series of AMS hyperbaric treatment profiles that LST has previously developed to the US military and NASA, and that take greater advantage of vasoconstrictive effects of oxygen under true hyperbaric conditions of 1.25 ATA. These profiles virtually eliminate AMS rebound after the initial treatment often seen in conventional AMS treatment, where the patient is either treated at altitude, or does not recompress back to sea level or greater pressure (1.25 ATA), but returns directly to the same altitude where AMS symptoms first manifested.
Controlled oxygen therapy and carbon dioxide retention during exacerbations of chronic obstructive pulmonary disease. [2015]Hypoxaemic patients with exacerbations of chronic obstructive pulmonary disease (COPD) are at some risk of carbon dioxide (CO2) retention during oxygen therapy. We quantified the risk of CO2 retention with oxygen therapy in COPD in 24 consecutive patients presenting to the accident and emergency department with acute exacerbations associated with hypercapnic respiratory failure (partial arterial pressure of oxygen [PaO2] or = 6.5 kPa). Only three patients developed clinically important CO2 retention (defined as a rise in PaCO2 > 1 kPa) with controlled oxygen therapy (24-40% by Venturi mask to maintain the oxygen saturation at 91-92%). These patients presented with more severe hypercapnia, but all three required only low-flow oxygen (24-28%). These findings suggest only a small risk of aggravating hypercapnia with controlled oxygen supplementation.