Hypercapnia in Orthostatic Hypotension
Trial statusRecruiting
Trial phaseNot applicable
Trial typeInterventional
Biological sexAll
Age18-100
SponsorUniversity of Calgary
About 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
Eligibility criteria
This trial accepts healthy volunteersQualifiers
Age ≥18 years
Male and Female
Non - smokers.
Able and willing to provide informed consent.
Disqualifiers
Medical therapies or medications which could interfere with testing of autonomic function
Participants with somatization or severe anxiety symptoms will be excluded
Pregnant or breast-feeding females
Inability to tolerate mask for the duration of the study
Trial design
Design model
Crossover
Treatments tested in this trial
Sequential Gas Delivery
DrugSequential Gas Delivery will be controlled using the RespirAct™ system (Thornhill Research Inc., Toronto, Canada)
Treatment groups
80 Participants
are divided into 5 treatment groupsGroup A: Room AirNo intervention 0 interventions
Group B: +0mmHg CO2 Clamped at baselineExperimental treatment 1 intervention
Group C: +5mmHg CO2Experimental treatment 1 intervention
Group D: +10mmHgExperimental treatment 1 intervention
Group E: +10mmHg CO2 + 50mmHg O2Experimental treatment 1 intervention
Trial outcomes
Primary outcomes
1
Δ Blood Pressure (BP)
Magnitude of ΔBP (Stand-Sit) breathing room air vs +10mmHg of CO2
Time frame
The ΔBP (stand-sit) calculated as the average BP in the final minute of sitting and the average BP between minute 3 and 5 of stand will be compared between room air and +10mmHg of CO2Secondary outcomes
1
Δ Blood Pressure (BP)
Magnitude of ΔBP (Stand-Sit) breathing room air vs 0 mmHg of CO2
Time frame
The ΔBP (stand-sit) calculated as the average BP in the final minute of sitting and the average BP between minute 3 and 5 of stand will be compared between room air and 0 mmHg of CO22
Δ Blood Pressure (BP)
Magnitude of ΔBP (Stand-Sit) breathing room air vs +5mmHg of CO2
Time frame
The ΔBP (stand-sit) calculated as the average BP in the final minute of sitting and the average BP between minute 3 and 5 of stand will be compared between room air and +5mmHg of CO23
Δ Blood Pressure (BP)
Magnitude of ΔBP (Stand-Sit) breathing room air vs +10mmHgCO2/50mmHg O2
Time frame
The ΔBP (stand-sit) calculated as the average BP in the final minute of sitting and the average BP between minute 3 and 5 of stand will be compared between room air and +10mmHgCO2/50mmHg O24
Δ Vanderbilt Orthostatic Symptom Score [Range: 0 (absent) to 10 (worst)]
Magnitude of Δ Vanderbilt Orthostatic Symptom Score (Stand-Sit) breathing room air vs +10mmHg of CO2
Time frame
The Δ Vanderbilt Orthostatic Symptom Score (symptoms at the 5th minute of stand - symptoms at the 5th minute of sit) will be compared between room air and +10mmHg of CO2Sponsors and contacts
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Source ClinicalTrials.gov