Healthy MalesPhase 4NCT01848665
The Influence of Cerebral Blood Flow and PETCO2 on Neuromuscular Function During Passive Heat Stress
A Phase 4 study testing Indomethacin in people with Healthy Males and Neuromuscular Function, run by Brock University at 1 site in Canada.
Trial summary
Increased core temperature (hyperthermia) has been associated with impaired neuromuscular performance; however, the mechanisms associated with these performance decrements and their potential synergies remain unclear. Read more about this study
- Who is it for?
- Ages 18 to 45 years, men onlyHealthy volunteers can take part
- Conditions the study is for
- Healthy Males, Neuromuscular Function
- What is being tested?
- Indomethacin
- Type of treatment
- Pill or oral medicine
- Could I receive a placebo?
- Yes, some participants may receive a placebo
- How many people
- 8 participants
- Where
- 1 siteCanada
- Study dates
- May 2013to Dec 2016
- Phase
- Phase 4
- Are there results?
- None posted in the registry
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 to 45 years
- Men only
- Healthy volunteers accepted
- Adult
Who may be able to join
- 18 to 45 yrs old; healthy males
Who cannot join
- diagnosed medical condition; NSAID allergy; smoker; high altitude exposure; implants
Trial locations and contacts
1 site in 1 country.
About this study
Increased core temperature (hyperthermia) has been associated with impaired neuromuscular performance; however, the mechanisms associated with these performance decrements and their potential synergies remain unclear. While the majority of research suggests that the observed fatigue is related to the central nervous system, the influence of changes in cerebral blood flow (CBF) and associated changes in cerebral alkalosis (estimated by end-tidal partial pressure of carbon dioxide; PETCO2) remains unexamined. In response to hyperthermia, humans hyperventilate as means of heat dissipation, resulting in a hypocapnia (reduced PETCO2) mediated decrease in CBF and consequently, cerebral alkalosis (increased cerebral pH). Previous research suggests that hyperventilation induces changes in neural excitability and synaptic transmission; however, it remains unclear if these changes are related to hypocapnia mediated decrease in CBF or decreased PETCO2 or both.
The purpose of the proposed research program is to examine the influence of changes in CBF and cerebral alkalosis on neuromuscular function during passive heat stress. The research project will consist of 3 separate experimental trials: (a) poikilocapnic hyperthermia (increased core temperature; decrease CBF; decrease PETCO2), (b) isocapnic hyperthermia (increased core temperature; no change CBF; no change PETCO2) and (c) isocapnic hyperthermia + indomethacin (increased core temperature; decrease CBF; no change PETCO2). During each manipulation, neuromuscular function will be evaluated and compared to baseline (normothermic) conditions using a repeated measures design.
It is hypothesized that changes in PETCO2 and therefore, changes in cerebral alkalosis will contribute to neuromuscular fatigue independent of changes in CBF or increases in core temperature.
- Conditions
- Healthy Males, Neuromuscular Function
- Being tested
- Indomethacin, Placebo
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
IndomethacinDrug
PlaceboDrug
| Study group | Role | What they receive |
|---|---|---|
| Drug | Experimental | Indomethacin, 1.2 mg kg 1 dose Receives: Drug: Indomethacin |
| Placebo | Placebo comparator | generic flour placebo capsule Receives: Drug: Placebo |
What is being measured
The primary outcome is the main question the study is designed to answer.
Resting motor threshold
Motor evoked potentials are recorded from muscles following transcranial magnetic stimulation of motor cortex. The resting motor threshold is defined as the minimum stimulation intensity required to elicit a motor evoked potential. Resting motor threshold will be quantified in millivolts.
Measured: Change from baseline 90-minutes
H-Reflex Amplitude
The H-Reflex is an indirect measure of motor neuron excitability. Initially, a maximal M-wave (M-max) will be elicited by stimulating (1 ms in duration; 15 s between stimuli) the median nerve incrementally (2 V increments) until the largest waveform is observed. The peak-to-peak amplitude of this waveform is considered M-max. Using similar procedures as above, a sub-maximal M-wave of 5% M-max will be elicited and the amplitude of the resultant H-reflex (a small waveform observed following the submaximal M-wave) will be calculated. The amplitude of the H-reflex will be quantified in millivolts.
Measured: Change from baseline 90-minutes
Maximal Voluntary Contraction
During maximal voluntary contraction (MVC) testing, the participants' right arm will be secured in a custom made device used to isolate forearm flexion and to measure force production by the flexor carpi radialis muscle. Participants will be asked to produce a 5-second MVC and will be verbally encouraged to maintain maximal force production throughout the duration of the contraction. MVC will be quantified as the maximum force production in newton meters.
Measured: Change from baseline 90-minutes
H-Reflex latency
The H-Reflex is an indirect measure of motor neuron excitability. Initially, a maximal M-wave (M-max) will be elicited by stimulating (1 ms in duration; 15 s between stimuli) the median nerve incrementally (2 V increments) until the largest waveform is observed. The peak-to-peak amplitude of this waveform is considered M-max. Using similar procedures as above, a sub-maximal M-wave of 5% M-max will be elicited and the amplitude of the resultant H-reflex (a small waveform observed following the submaximal M-wave) will be calculated. The onset latency of the H-reflex will be quantified in milliseconds.
Measured: Change from baseline 90-minutes
Voluntary Activation
The level of neural drive to muscle during contraction is termed voluntary activation and will be estimated by interpolation of a single supramaximal motor evoked potential during the 5-second MVC contraction. If extra force is evoked by the 'superimposed' stimulus then either the stimulated axons were not all recruited voluntarily or they were discharging at sub-tetanic rates. Therefore, voluntary activation will be quantified as the amplitude of maximal voluntary force production, relative to the amplitude of the supramaximal MEP.
Measured: change from baseline 90-minutes
Secondary outcomes (6)
Middle Cerebral Artery Blood Flow Velocity
Middle cerebral artery (MCA) blood flow velocity will be measured non-invasively by a 2-MHz transcranial Doppler (TCD) ultrasound probe, attached bilaterally to a comfortable headband and secured anterior to the zygomatic arch, rostral of the pinna. Doppler probes will be paced over the temporal windows (near the ear) and will remain in place throughout the duration of the experimental protocol. MCA velocity will be quantified in cm/s.
Measured: Change from baseline 90-minutes
Blood Pressure
Beat by beat blood pressure will be calculated from the blood pressure waveform using finger photoplethysmography (Nexfin, bmeye), with a finger cuff placed directly over the middle finger on the left hand. Blood pressure will be quantified in mmHg.
Measured: Change from baseline 90-minutes
Heart rate
Heart rate will be measured by electrocardiogram. Heart rate will be quantified in beats per minute.
Measured: Change from baseline 90-minutes
End-tidal Gas concentrations
The end-tidal concentrations of oxygen and carbon dioxide will be measured and reported in mmHg.
Measured: change from baseline 90-minutes
Rectal Temperature
Rectal temperature will be measured in degrees Celsius
Measured: change from baseline 90-minutes
Skin Temperature
skin temperature will be measured in degrees Celsius
Measured: change from baseline 90-minutes
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted7 May 2013 (estimated)
- Study startMay 2013
- Primary completionJun 2015
- Study completionDec 2016
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Healthy MalesStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase 4
- Primary purpose
- Basic science
- Allocation
- Randomised
- Intervention model
- Single group
- Masking
- Single blind
- Who is masked
- Participant
- Enrolment
- 8 participants (actual)
Sponsor and investigators
- Lead sponsor
- Brock University
- Sponsor type
- University, hospital or other
- Responsible party
- Principal investigator, Stephen Cheung, Brock University
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT01848665
- Sponsor's protocol ID
- EEL 073.3
- Status last verified
- Jan 2018
- First submitted
- 3 May 2013
- Last updated
- 29 Jan 2018
- Results posted
- No
Study at a glance
From the registry record, last updated by the sponsor on 29 Jan 2018. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- The Influence of Cerebral Blood Flow and PETCO2 on Neuromuscular Function During Passive Heat Stress
- ClinicalTrials.gov ID
- NCT01848665
- Acronym / sponsor ID
- EEL 073.3
- Conditions
- Healthy Males, Neuromuscular Function
- Phase
- Phase 4
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 8 participants (actual)
- Lead sponsor
- Brock UniversityUniversity, hospital or other
- Study start
- May 2013
- Primary completion
- Jun 2015 (actual)
- Study completion
- Dec 2016 (actual)
- First posted
- 7 May 2013 (estimated)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
Increased core temperature (hyperthermia) has been associated with impaired neuromuscular performance; however, the mechanisms associated with these performance decrements and their potential synergies remain unclear. While the majority of research suggests that the observed fatigue is related to the central nervous system, the influence of changes in cerebral blood flow (CBF) and associated changes in cerebral alkalosis (estimated by end-tidal partial pressure of carbon dioxide; PETCO2) remains unexamined. In response to hyperthermia, humans hyperventilate as means of heat dissipation, resulting in a hypocapnia (reduced PETCO2) mediated decrease in CBF and consequently, cerebral alkalosis (increased cerebral pH). Previous research suggests that hyperventilation induces changes in neural excitability and synaptic transmission; however, it remains unclear if these changes are related to hypocapnia mediated decrease in CBF or decreased PETCO2 or both.
The purpose of the proposed research program is to examine the influence of changes in CBF and cerebral alkalosis on neuromuscular function during passive heat stress. The research project will consist of 3 separate experimental trials: (a) poikilocapnic hyperthermia (increased core temperature; decrease CBF; decrease PETCO2), (b) isocapnic hyperthermia (increased core temperature; no change CBF; no change PETCO2) and (c) isocapnic hyperthermia + indomethacin (increased core temperature; decrease CBF; no change PETCO2). During each manipulation, neuromuscular function will be evaluated and compared to baseline (normothermic) conditions using a repeated measures design.
It is hypothesized that changes in PETCO2 and therefore, changes in cerebral alkalosis will contribute to neuromuscular fatigue independent of changes in CBF or increases in core temperature.
Study design
- Primary purpose
- Basic science
- Allocation
- Randomised
- Intervention model
- Single group
- Masking
- Single blind (participant)
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| Drug | Experimental | Drug: IndomethacinIndomethacin, 1.2 mg kg 1 dose |
| Placebo | Placebo comparator | Drug: Placebogeneric flour placebo capsule |
Who may qualify
- Ages
- 18 to 45 years
- Sex
- Male only
- Healthy volunteers
- Accepted
- Age groups
- Adult
Key inclusion criteria (1 listed)
- 18 to 45 yrs old; healthy males
Key exclusion criteria (1 listed)
- diagnosed medical condition; NSAID allergy; smoker; high altitude exposure; implants
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Indomethacin | Drug | Drug |
| Placebo | Drug | Placebo |
Primary outcome
Resting motor threshold
Time frame: Change from baseline 90-minutes
Motor evoked potentials are recorded from muscles following transcranial magnetic stimulation of motor cortex. The resting motor threshold is defined as the minimum stimulation intensity required to elicit a motor evoked potential. Resting motor threshold will be quantified in millivolts.
H-Reflex Amplitude
Time frame: Change from baseline 90-minutes
The H-Reflex is an indirect measure of motor neuron excitability. Initially, a maximal M-wave (M-max) will be elicited by stimulating (1 ms in duration; 15 s between stimuli) the median nerve incrementally (2 V increments) until the largest waveform is observed. The peak-to-peak amplitude of this waveform is considered M-max. Using similar procedures as above, a sub-maximal M-wave of 5% M-max will be elicited and the amplitude of the resultant H-reflex (a small waveform observed following the submaximal M-wave) will be calculated. The amplitude of the H-reflex will be quantified in millivolts.
Maximal Voluntary Contraction
Time frame: Change from baseline 90-minutes
During maximal voluntary contraction (MVC) testing, the participants' right arm will be secured in a custom made device used to isolate forearm flexion and to measure force production by the flexor carpi radialis muscle. Participants will be asked to produce a 5-second MVC and will be verbally encouraged to maintain maximal force production throughout the duration of the contraction. MVC will be quantified as the maximum force production in newton meters.
H-Reflex latency
Time frame: Change from baseline 90-minutes
The H-Reflex is an indirect measure of motor neuron excitability. Initially, a maximal M-wave (M-max) will be elicited by stimulating (1 ms in duration; 15 s between stimuli) the median nerve incrementally (2 V increments) until the largest waveform is observed. The peak-to-peak amplitude of this waveform is considered M-max. Using similar procedures as above, a sub-maximal M-wave of 5% M-max will be elicited and the amplitude of the resultant H-reflex (a small waveform observed following the submaximal M-wave) will be calculated. The onset latency of the H-reflex will be quantified in milliseconds.
Voluntary Activation
Time frame: change from baseline 90-minutes
The level of neural drive to muscle during contraction is termed voluntary activation and will be estimated by interpolation of a single supramaximal motor evoked potential during the 5-second MVC contraction. If extra force is evoked by the 'superimposed' stimulus then either the stimulated axons were not all recruited voluntarily or they were discharging at sub-tetanic rates. Therefore, voluntary activation will be quantified as the amplitude of maximal voluntary force production, relative to the amplitude of the supramaximal MEP.
6 secondary outcomes
Middle Cerebral Artery Blood Flow Velocity
Time frame: Change from baseline 90-minutes
Blood Pressure
Time frame: Change from baseline 90-minutes
Heart rate
Time frame: Change from baseline 90-minutes
End-tidal Gas concentrations
Time frame: change from baseline 90-minutes
Rectal Temperature
Time frame: change from baseline 90-minutes
Skin Temperature
Time frame: change from baseline 90-minutes
Results and safety
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 29 Jan 2018.
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
The record lists no contact. Use the official record to reach the sponsor.
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A Phase 4 study testing Indomethacin in people with Healthy Males and Neuromuscular Function, run by Brock University at 1 site in Canada.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 1 inclusion and 1 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: finished, as of the sponsor's last update on 29 Jan 2018. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in Canada. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. Some participants in this study may receive a placebo. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
What does this phase mean?
Phase 4 studies take place after a treatment is approved, to learn more about its long-term benefits and risks in everyday use.
Not every study follows the same path, and some studies (observational studies, device studies) have no phase.
Are results available for this study?
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Resting motor threshold (time frame: Change from baseline 90-minutes). The study lists 5 primary outcomes in all. It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 29 Jan 2018.