Airway Complication of AnaesthesiaPhase 4NCT01557920
The Effects of General Anesthetics on Upper Airway Collapsibility in Healthy Subjects
A Phase 4 study testing Propofol and Sevoflurane in people with Airway Complication of Anaesthesia and Healthy, run by Massachusetts General Hospital at 1 site in United States.
Trial summary
The investigators hypothesize that propofol, when compared to sevoflurane, causes the upper airway to collapse more easily and causes less activity in the tongue muscle. Additionally, the investigators hypothesize that, under increased carbon dioxide concentrations of the air inhaled, the upper airway will be less… Read more about this study
- Who is it for?
- Ages 18 to 45 yearsHealthy volunteers can take part
- Conditions the study is for
- Airway Complication of Anaesthesia, Healthy
- What is being tested?
- Propofol and Sevoflurane
- Type of treatment
- Injection or infusion
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 18 participants
- Where
- 1 siteUnited States
- Study dates
- Jan 2013to Mar 2014
- Phase
- Phase 4
- Are there results?
- Yes, posted in the registrySummary in the doctors' view
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
- All sexes
- Healthy volunteers accepted
- Adult
Who may be able to join
- American Society of Anesthesiologists (ASA) class I
- Age between 18 and 45
- BMI 18-28 kg/m^2
Who cannot join
- Concurrent significant medical illness (heart disease including untreated hypertension, Clinically significant kidney disease, liver disease, or lung disease, History of myasthenia gravis or other muscle and nerve disease)
- Anxiety disorder requiring treatment
- Concurrent medications known to affect anesthesia, upper airway muscles or respiratory function (e.g., gabaergic anxiolytics, antipsychotics)
- Individuals with a history of allergy or adverse reaction to lidocaine, propofol, or sevoflurane
- For women: pregnancy
- Suggestion of obstructive sleep apnea (OSA) or any other sleep disorder (e.g. witnessed apneas, gasping or choking during sleep, unexplained excessive daytime sleepiness)
- History of drug or alcohol abuse
- Acute intermittent porphyria
Trial locations and contacts
1 site in 1 country.
United States1 site
Massachusetts General Hospital
Boston, Massachusetts, 02114
About this study
Official title: The Effects of Sevoflurane, Propofol, and Carbon Dioxide 'Reversal' on Upper Airway Collapsibility in Healthy, Adult Subjects
The investigators hypothesize that propofol, when compared to sevoflurane, causes the upper airway to collapse more easily and causes less activity in the tongue muscle. Additionally, the investigators hypothesize that, under increased carbon dioxide concentrations of the air inhaled, the upper airway will be less likely to collapse under anesthesia and there will be increased activity in the tongue muscle under both propofol and sevoflurane, when compared to breathing normal concentrations of carbon dioxide, as in room air. Furthermore the investigators hypothesize that anesthesia disrupt the breathing swallow coordination, an effect additionally altered by increased carbon dioxide through increased respiratory drive.
Read the detailed description
Upper airway patency depends on an appropriate balance between the dilating force of pharyngeal muscles and the collapsing force of negative intraluminal pressure, which is generated by respiratory "pump" muscles. The genioglossus (GG) protects pharyngeal patency in humans. This muscle receives various types of neural drive, distributed differentially across the hypoglossal motoneuron pool, including phasic (inspiratory) and tonic (non-respiratory) drives. In addition, reflex GG activation in response to negative pharyngeal pressure stabilizes upper airway patency both in humans and in rats. General anesthetic agents, including propofol and sevoflurane, predispose the upper airway to collapse, at least in part by decreasing upper airway muscle activity.
Theoretically anesthetics could affect upper airway dilator activity by several mechanisms, including an anesthetic-induced, dose-dependent decrease in hypercapnic and hypoxic ventilatory drive, hypoglossal motoneuron depression, decreased skeletal muscle contractility, an increase in phasic GG activity as a result of decreased arterial blood pressure, and an increase in phasic hypoglossal nerve discharge.
Previous studies have shown that certain anesthetics, including pentobarbital and isoflurane, can increase genioglossus phasic activity in rats and in humans. The effects of propofol on airway collapsibility have been studied in humans however, to our knowledge, they have not been measured under conditions of hypercapnia. Studies of airway collapsibility under sevoflurane anesthesia have been performed in children, but no data exists for airway collapsibility in sevoflurane-anesthetized adults. Similarly no data exists on the effects of sevoflurane on GG activity
In a previous trial of pentobarbital-anesthetized volunteers, the investigators observed that mild hypercapnia (5 - 10 mmHg above baseline) produced a significant increase in flow rate and GG phasic activity, as well as a smaller increase in GG tonic activity. If our proposed study shows a beneficial effect, then the investigators plan a follow-up study addressing the possibility that hypercapnia may be used therapeutically for airway protection. A similar concept has already been considered for critically ill ICU patients.
However, previous studies have shown that a hypercapnia-induced increase in ventilatory drive can inhibit airway protective reflexes by disrupting the breathing swallowing coordination. In order to assess the safety of induced mild hypercapnia as an intervention for airway protection, we evaluated whether variable levels of hypercapnia occurring during anesthesia with sevoflurane and propofol impair the coordination of breathing and swallowing compared with the effects of anesthesia alone.
With this pharmaco-physiological interaction study on healthy adults we aim to:
- Compare the effects of sevoflurane and propofol on upper airway closing pressure, upper airway muscle control and breathing.
- Assess the effects of evoked hypercapnia (carbon dioxide reversal) on propofol-induced upper airway collapsibility
- Evaluate the effects of sevoflurane, propofol, and induced hypercapnia on coordination of breathing and swallowing.
Comparative drug studies on airway effects of anesthetics in humans are important for defining an optimal anesthetic regimen for patients at risk of airway collapse, such as patients with obstructive sleep apnea. Our studies are also particularly relevant for patients undergoing procedural sedation, which is typically being conducted under spontaneous ventilation with the upper airway being unprotected. In addition, our results may increase our understanding of postoperative airway obstruction, a common complication in the post-anesthesia recovery room.
- Conditions
- Airway Complication of Anaesthesia, Healthy
- Being tested
- Propofol, Sevoflurane
- Keywords
- apnea, airway collapsibility, healthy, hypercapnia, general anesthesia, breathing-swallow coordination, aspiration
- Medical subject headings
- Apnea, Hypercapnia
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
PropofolDrug
Propofol administration for induction of general anesthesia. Administration will be performed IV, using a Target Controlled Induction Pump.
SevofluraneDrug
Sevoflurane will be administered via mask inhalation to achieve anesthesia.
| Study group | Role | What they receive |
|---|---|---|
| Propofol | Active comparator | The healthy subject will be anesthetized with Propofol. Respiratory measurements will be taken while the subject is anesthetized to calculate the airway closing pressure. After recovery from anesthesia, airway diameter and duty cycle will also be measured. In addition to breathing air mixture, subject will be given carbon dioxide to achieve end tidal CO2 levels of 4 mm and 8 mm above baseline. All respiratory measurements will be repeated at each level above baseline. Assessment of swallow patterns during anesthesia and wakefulness, as well as under differential CO2 levels will be assessed offline after recovery from anesthesia. Receives: Drug: Propofol |
| Sevoflurane | Active comparator | The healthy subject will be anesthetized with Sevoflurane. Respiratory measurements will be taken while the subject is anesthetized to calculate the airway closing pressure. After recovery from anesthesia, airway diameter and duty cycle will also be measured. In addition to breathing air mixture, subject will be given carbon dioxide to achieve end tidal CO2 levels of 4 mm and 8 mm above baseline. All respiratory measurements will be repeated at each level above baseline. Assessment of swallow patterns during anesthesia and wakefulness, as well as under differential CO2 levels will be assessed offline after recovery from anesthesia. Receives: Drug: Sevoflurane |
What is being measured
The primary outcome is the main question the study is designed to answer.
Upper Airway Closing Pressure
Upper airway closing pressure will be measured during steady state anesthesia as well as during carbon dioxide reversal.
Measured: participants will be followed for the duration of anesthesia, an expected average of 6 hours
Proportion of Pathological Swallows
A pathological swallow was defined as a swallow that was followed by inspiratory flow. A physiological swallow was defined as a swallow that was followed by expiratory flow. The number of pathological and physiological swallows were measured during wakefulness and anesthesia. The pathological swallows are presented as percentage of path. swallows calculated as path.sw/[path.sw+phys.sw]*100 (%).
Measured: swallows were measured during steady state conditions (mean±SEM, 2.6±0.6h)
Secondary outcomes (4)
Airway Diameter
Using acoustic pharyngometry, we intend to measure the cross-sectional area of the airway at several points during recovery from anesthesia.
Measured: participants will be followed for the duration of anesthesia until full recovery, an expected average of 9 hours
Genioglossus Muscle Electromyogram
will be measured during steady state anesthesia as well as during carbon dioxide reversal, and during recovery from anesthesia.
Measured: participants will be followed for the duration of anesthesia until full recovery, an expected average of 9 hours
Minute Ventilation (Tidal Volume and Respiratory Rate)
Measured by spirometry. Subjects wear a full-face mask. Reported in L/min
Measured: Will be measured before and during anesthesia until emergence from anesthesia, an expected average of 6 hours
Duty Cycle
(T(ins)/T(total))*100
Measured: Will be measured before and during anesthesia until emergence from anesthesia, an expected average of 6 hours
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted20 Mar 2012 (estimated)
- Study startJan 2013
- Primary completionNov 2013
- Study completionMar 2014
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Posted resultsParticipant flow, outcome measures and adverse events reported by the sponsor.
- Publications (3)Papers the sponsor has linked to this study.
- Other trials for Airway Complication of AnaesthesiaStudies of the same condition, open and under way.
- More trials run by Massachusetts General HospitalThe sponsor's other registered studies.
- 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
- Prevention
- Allocation
- Randomised
- Intervention model
- Crossover
- Masking
- Single blind
- Who is masked
- Participant
- Enrolment
- 18 participants (actual)
Sponsor and investigators
- Lead sponsor
- Massachusetts General Hospital
- Sponsor type
- University, hospital or other
- Responsible party
- Principal investigator, Matthias Eikermann, Massachusetts General Hospital
- Investigators
- Matthias Eikermann, MD, PhD, Principal investigator, Massachusetts General Hospital
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT01557920
- Sponsor's protocol ID
- 2011P002472
- Status last verified
- Aug 2016
- First submitted
- 15 Mar 2012
- Last updated
- 13 Sep 2016
- Results posted
- Yes, on ClinicalTrials.gov
- Data monitoring committee
- No
Publications
Eikermann M, Malhotra A, Fassbender P, Zaremba S, Jordan AS, Gautam S, White DP, Chamberlin NL. Differential effects of isoflurane and propofol on upper airway dilator muscle activity and breathing. Anesthesiology. 2008 May;108(5):897-906. doi: 10.1097/ALN.0b013e31816c8a60.
PubMed 18431126Eikermann M, Grosse-Sundrup M, Zaremba S, Henry ME, Bittner EA, Hoffmann U, Chamberlin NL. Ketamine activates breathing and abolishes the coupling between loss of consciousness and upper airway dilator muscle dysfunction. Anesthesiology. 2012 Jan;116(1):35-46. doi: 10.1097/ALN.0b013e31823d010a.
PubMed 22108392Eikermann M, Eckert DJ, Chamberlin NL, Jordan AS, Zaremba S, Smith S, Rosow C, Malhotra A. Effects of pentobarbital on upper airway patency during sleep. Eur Respir J. 2010 Sep;36(3):569-76. doi: 10.1183/09031936.00153809. Epub 2009 Dec 23.
PubMed 20032012
Study at a glance
From the registry record, last updated by the sponsor on 13 Sep 2016. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- The Effects of Sevoflurane, Propofol, and Carbon Dioxide 'Reversal' on Upper Airway Collapsibility in Healthy, Adult Subjects
- ClinicalTrials.gov ID
- NCT01557920
- Acronym / sponsor ID
- 2011P002472
- Conditions
- Airway Complication of Anaesthesia, Healthy
- Keywords
- apnea, airway collapsibility, healthy, hypercapnia, general anesthesia, breathing-swallow coordination, aspiration
- Phase
- Phase 4
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 18 participants (actual)
- Lead sponsor
- Massachusetts General HospitalUniversity, hospital or other
- Study start
- Jan 2013
- Primary completion
- Nov 2013 (actual)
- Study completion
- Mar 2014 (actual)
- First posted
- 20 Mar 2012 (estimated)
- Results
- Posted 21 Apr 2016
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
The investigators hypothesize that propofol, when compared to sevoflurane, causes the upper airway to collapse more easily and causes less activity in the tongue muscle. Additionally, the investigators hypothesize that, under increased carbon dioxide concentrations of the air inhaled, the upper airway will be less likely to collapse under anesthesia and there will be increased activity in the tongue muscle under both propofol and sevoflurane, when compared to breathing normal concentrations of carbon dioxide, as in room air. Furthermore the investigators hypothesize that anesthesia disrupt the breathing swallow coordination, an effect additionally altered by increased carbon dioxide through increased respiratory drive.
Detailed description
Upper airway patency depends on an appropriate balance between the dilating force of pharyngeal muscles and the collapsing force of negative intraluminal pressure, which is generated by respiratory "pump" muscles. The genioglossus (GG) protects pharyngeal patency in humans. This muscle receives various types of neural drive, distributed differentially across the hypoglossal motoneuron pool, including phasic (inspiratory) and tonic (non-respiratory) drives. In addition, reflex GG activation in response to negative pharyngeal pressure stabilizes upper airway patency both in humans and in rats. General anesthetic agents, including propofol and sevoflurane, predispose the upper airway to collapse, at least in part by decreasing upper airway muscle activity.
Theoretically anesthetics could affect upper airway dilator activity by several mechanisms, including an anesthetic-induced, dose-dependent decrease in hypercapnic and hypoxic ventilatory drive, hypoglossal motoneuron depression, decreased skeletal muscle contractility, an increase in phasic GG activity as a result of decreased arterial blood pressure, and an increase in phasic hypoglossal nerve discharge.
Previous studies have shown that certain anesthetics, including pentobarbital and isoflurane, can increase genioglossus phasic activity in rats and in humans. The effects of propofol on airway collapsibility have been studied in humans however, to our knowledge, they have not been measured under conditions of hypercapnia. Studies of airway collapsibility under sevoflurane anesthesia have been performed in children, but no data exists for airway collapsibility in sevoflurane-anesthetized adults. Similarly no data exists on the effects of sevoflurane on GG activity
In a previous trial of pentobarbital-anesthetized volunteers, the investigators observed that mild hypercapnia (5 - 10 mmHg above baseline) produced a significant increase in flow rate and GG phasic activity, as well as a smaller increase in GG tonic activity. If our proposed study shows a beneficial effect, then the investigators plan a follow-up study addressing the possibility that hypercapnia may be used therapeutically for airway protection. A similar concept has already been considered for critically ill ICU patients.
However, previous studies have shown that a hypercapnia-induced increase in ventilatory drive can inhibit airway protective reflexes by disrupting the breathing swallowing coordination. In order to assess the safety of induced mild hypercapnia as an intervention for airway protection, we evaluated whether variable levels of hypercapnia occurring during anesthesia with sevoflurane and propofol impair the coordination of breathing and swallowing compared with the effects of anesthesia alone.
With this pharmaco-physiological interaction study on healthy adults we aim to:
- Compare the effects of sevoflurane and propofol on upper airway closing pressure, upper airway muscle control and breathing.
- Assess the effects of evoked hypercapnia (carbon dioxide reversal) on propofol-induced upper airway collapsibility
- Evaluate the effects of sevoflurane, propofol, and induced hypercapnia on coordination of breathing and swallowing.
Comparative drug studies on airway effects of anesthetics in humans are important for defining an optimal anesthetic regimen for patients at risk of airway collapse, such as patients with obstructive sleep apnea. Our studies are also particularly relevant for patients undergoing procedural sedation, which is typically being conducted under spontaneous ventilation with the upper airway being unprotected. In addition, our results may increase our understanding of postoperative airway obstruction, a common complication in the post-anesthesia recovery room.
Study design
- Primary purpose
- Prevention
- Allocation
- Randomised
- Intervention model
- Crossover
- Masking
- Single blind (participant)
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| Propofol | Active comparator | Drug: PropofolThe healthy subject will be anesthetized with Propofol. Respiratory measurements will be taken while the subject is anesthetized to calculate the airway closing pressure. After recovery from anesthesia, airway diameter and duty cycle will also be measured. In addition to breathing air mixture, subject will be given carbon dioxide to achieve end tidal CO2 levels of 4 mm and 8 mm above baseline. All respiratory measurements will be repeated at each level above baseline. Assessment of swallow patterns during anesthesia and wakefulness, as well as under differential CO2 levels will be assessed offline after recovery from anesthesia. |
| Sevoflurane | Active comparator | Drug: SevofluraneThe healthy subject will be anesthetized with Sevoflurane. Respiratory measurements will be taken while the subject is anesthetized to calculate the airway closing pressure. After recovery from anesthesia, airway diameter and duty cycle will also be measured. In addition to breathing air mixture, subject will be given carbon dioxide to achieve end tidal CO2 levels of 4 mm and 8 mm above baseline. All respiratory measurements will be repeated at each level above baseline. Assessment of swallow patterns during anesthesia and wakefulness, as well as under differential CO2 levels will be assessed offline after recovery from anesthesia. |
Who may qualify
- Ages
- 18 to 45 years
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Adult
Key inclusion criteria (3 listed)
- American Society of Anesthesiologists (ASA) class I
- Age between 18 and 45
- BMI 18-28 kg/m^2
Key exclusion criteria (8 listed)
- Concurrent significant medical illness (heart disease including untreated hypertension, Clinically significant kidney disease, liver disease, or lung disease, History of myasthenia gravis or other muscle and nerve disease)
- Anxiety disorder requiring treatment
- Concurrent medications known to affect anesthesia, upper airway muscles or respiratory function (e.g., gabaergic anxiolytics, antipsychotics)
- Individuals with a history of allergy or adverse reaction to lidocaine, propofol, or sevoflurane
- For women: pregnancy
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 |
|---|---|---|
| PropofolPropofol administration for induction of general anesthesia. Administration will be performed IV, using a Target Controlled Induction Pump. | Drug | Propofol |
| SevofluraneSevoflurane will be administered via mask inhalation to achieve anesthesia. | Drug | Sevoflurane |
Primary outcome
Upper Airway Closing Pressure
Time frame: participants will be followed for the duration of anesthesia, an expected average of 6 hours
Upper airway closing pressure will be measured during steady state anesthesia as well as during carbon dioxide reversal.
Proportion of Pathological Swallows
Time frame: swallows were measured during steady state conditions (mean±SEM, 2.6±0.6h)
A pathological swallow was defined as a swallow that was followed by inspiratory flow. A physiological swallow was defined as a swallow that was followed by expiratory flow. The number of pathological and physiological swallows were measured during wakefulness and anesthesia. The pathological swallows are presented as percentage of path. swallows calculated as path.sw/[path.sw+phys.sw]*100 (%).
4 secondary outcomes
Airway Diameter
Time frame: participants will be followed for the duration of anesthesia until full recovery, an expected average of 9 hours
Genioglossus Muscle Electromyogram
Time frame: participants will be followed for the duration of anesthesia until full recovery, an expected average of 9 hours
Minute Ventilation (Tidal Volume and Respiratory Rate)
Time frame: Will be measured before and during anesthesia until emergence from anesthesia, an expected average of 6 hours
Duty Cycle
Time frame: Will be measured before and during anesthesia until emergence from anesthesia, an expected average of 6 hours
Results and safety
Loading the posted results from ClinicalTrials.gov…
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 13 Sep 2016.
- Posted resultsParticipant flow, baseline, all outcome measures and adverse events.
- Background: PubMed 18431126Eikermann M, Malhotra A, Fassbender P, Zaremba S, Jordan AS, Gautam S, White DP, Chamberlin NL. Differential effects of isoflurane and propofol on upper airway dilator muscle activity and breathing. Anesthesiology. 2008 May;108(5):897-906. doi: 10.1097/ALN.0b013e31816c8a60.
- Background: PubMed 22108392Eikermann M, Grosse-Sundrup M, Zaremba S, Henry ME, Bittner EA, Hoffmann U, Chamberlin NL. Ketamine activates breathing and abolishes the coupling between loss of consciousness and upper airway dilator muscle dysfunction. Anesthesiology. 2012 Jan;116(1):35-46. doi: 10.1097/ALN.0b013e31823d010a.
- Background: PubMed 20032012Eikermann M, Eckert DJ, Chamberlin NL, Jordan AS, Zaremba S, Smith S, Rosow C, Malhotra A. Effects of pentobarbital on upper airway patency during sleep. Eur Respir J. 2010 Sep;36(3):569-76. doi: 10.1183/09031936.00153809. Epub 2009 Dec 23.
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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.
Matthias Eikermann, MD, PhD principal investigator
Massachusetts General Hospital
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 Propofol and Sevoflurane in people with Airway Complication of Anaesthesia and Healthy, run by Massachusetts General Hospital at 1 site in United States.
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 3 inclusion and 8 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 13 Sep 2016. 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 United States. 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. 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?
Yes. Results are posted in the registry (first posted 21 Apr 2016). A summary is in the For doctors view, and the full results are on ClinicalTrials.gov.
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?
Upper Airway Closing Pressure (time frame: participants will be followed for the duration of anesthesia, an expected average of 6 hours). The study lists 2 primary outcomes in all. It is what the study was designed to measure, not a finding.
Where can I read the original study information?
On the ClinicalTrials.gov record for NCT01557920, which also lists 3 linked publications.
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 13 Sep 2016.