Cardiopulmonary BypassNCT02471950
Isoflurane During Cardiopulmonary Bypass
An observational study of Cardiopulmonary Bypass and Consciousness Monitors, run by University of Edinburgh at 1 site in United Kingdom.
Trial summary
There is no clinical way of assessing the depth of anaesthesia while patients are on the heart-lung machine. A new method of measuring the depth of anaesthesia using brainwaves called the Bispectral index (BIS) has been developed and its use in cardiac surgery is now widespread. Read more about this study
- Who is it for?
- Ages 18 years and older
- Conditions the study is for
- Cardiopulmonary Bypass, Consciousness Monitors, Isoflurane
- What is being tested?
- 2.5 % Isoflurane administration
- Type of treatment
- Surgery or procedure
- How many people
- 22 participants
- Where
- 1 siteUnited Kingdom
- Study dates
- Apr 2015to Jan 2019
- Phase
- Observational
- 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 years and older
- All sexes
- No healthy volunteers
- Adult, Older adult
Study population: Those patients scheduled for elective heart surgery over the age of 18 requiring cardiopulmonary bypass
Who may be able to join
- Participants over the age of 18
- Scheduled for elective cardiac surgery under the care of trial anaesthetists
- Patient has provided informed consent to participate
Who cannot join
- Patients presenting for emergency cardiac surgery
- Patients who will have cardiac surgery that does not require cardiopulmonary bypass
- Unwilling/unable to provide informed consent
- Patients under the age of 18
- Anaesthesia undertaken by anaesthetists not involved in trial
Trial locations and contacts
1 site in 1 country.
United Kingdom1 site
Royal Infirmary of Edinburgh
Edinburgh, Scotland, EH16 4SA
About this study
Official title: The Depth of Anaesthesia Associated With the Use of 2.5% Isoflurane During Cardiopulmonary Bypass
There is no clinical way of assessing the depth of anaesthesia while patients are on the heart-lung machine. A new method of measuring the depth of anaesthesia using brainwaves called the Bispectral index (BIS) has been developed and its use in cardiac surgery is now widespread. However BIS is also altered by patients body temperature. As cooling is common during heart surgery the use of BIS to measure the depth of anaesthesia during heart-lung bypass remains controversial. This study aims to find out what depth of anaesthesia is produced according to BIS during heart lung bypass using a standard anaesthetic technique that utilises the anaesthetic isoflurane.
Read the detailed description
There is no clinical way of assessing patients' depth of anaesthesia on the heart-lung machine. For this reason, the amount of volatile anaesthetic agent like isoflurane, that is administered has traditionally been determined by anaesthetists' clinical experience. Recently, a device that assesses depth of anaesthesia by analysing the electrical brain waves called the Bispectral index (BIS) has been introduced. The study aims to determine whether the level of anaesthesia produced by isoflurane using the traditional approach is more than required simply to maintain unconsciousness according to BIS. In addition, the study will determine whether the concentration of isoflurane in exhaust gases from the heart-lung machine can be used as an estimate arterial blood concentration and so, depth of anaesthesia.
The study will recruit patients who are scheduled for heart surgery using a heart-lung machine. Patients will be anaesthetised using a long established balanced technique including the administration of isoflurane 2.5% whilst supported on the heart-lung machine. Measurements of exhaust gas concentration of isoflurane from the heart-lung machine and level of BIS will be recorded at three time points. Simultaneously, three arterial blood samples will be taken and the isoflurane concentration measured in these samples. The BIS levels will be averaged and the proportion of patients with a BIS below 40 (lower limit of normal) will be calculated. Concentrations of isoflurane in the exhaust gas of the heart-lung machine will be compared with blood concentrations of isoflurane and the both concentrations will be compared with the level of BIS to establish whether they can be used to assess depth of anaesthesia.
If this study finds that a large proportion of patients have more than adequate levels of anaesthesia, then future studies could explore whether administering lower concentrations of isoflurane improves outcome whilst maintaining anaesthesia.
- Conditions
- Cardiopulmonary Bypass, Consciousness Monitors, Isoflurane
- Being tested
- 2.5 % Isoflurane administration
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
2.5 % Isoflurane administrationProcedure or surgery
Anaesthesia maintained during cardiopulmonary bypass with 2.5% isoflurane administered via the oxygenator of the bypass circuit.
| Study group | Role | What they receive |
|---|---|---|
| Elective Cardiac surgery | Those patients scheduled for elective heart surgery requiring cardiopulmonary bypass who will be given 2.5% isoflurane while on bypass. Receives: Procedure: 2.5 % Isoflurane administration |
What is being measured
The primary outcome is the main question the study is designed to answer.
Depth of anesthesia according to BIS
BIS reading will be recorded at three time points during cardiopulmonary bypass
Measured: Intraoperative
Secondary outcomes (3)
Comparison of exhaust gas and blood concentration of isoflurane
Exhaust gas and blood concentrations of isoflurane will be recorded at three time points during the operation. These values will be compared to see if their values are are related.
Measured: Intraoperative
Comparison of blood isoflurane concentration and BIS score
Blood isoflurane concentration and BIS will be recorded at three time points and compared to see if they are related
Measured: Intraoperative
Comparison of exhaust isoflurane Concentration and BIS score
Exhaust isoflurane and BIS will be recorded at three time points and compared to see they are related.
Measured: Intraoperative
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted15 Jun 2015 (estimated)
- Study startApr 2015
- Primary completionJan 2019
- Study completionJan 2019
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Publications (1)Papers the sponsor has linked to this study.
- Other trials for Cardiopulmonary BypassStudies 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
- Observational
- Observational model
- Cohort
- Time perspective
- Prospective
- Enrolment
- 22 participants (actual)
Sponsor and investigators
- Lead sponsor
- University of Edinburgh
- Sponsor type
- University, hospital or other
- Responsible party
- Sponsor
- Investigators
- Peter Alston, MBChB, Principal investigator, University of Edinburgh
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT02471950
- Sponsor's protocol ID
- 15 LO 0366
- Other IDs
- 2015/0199
- Status last verified
- Jun 2021
- First submitted
- 1 Jun 2015
- Last updated
- 21 Jun 2021
- Results posted
- No
- Data monitoring committee
- No
Publications
Alston RP, Connelly M, MacKenzie C, Just G, Homer N. The depth of anaesthesia associated with the administration of isoflurane 2.5% during cardiopulmonary bypass. Perfusion. 2019 Jul;34(5):392-398. doi: 10.1177/0267659118822946. Epub 2019 Jan 12.
PubMed 30638148
Study at a glance
From the registry record, last updated by the sponsor on 21 Jun 2021. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- The Depth of Anaesthesia Associated With the Use of 2.5% Isoflurane During Cardiopulmonary Bypass
- ClinicalTrials.gov ID
- NCT02471950
- Acronym / sponsor ID
- 15 LO 0366
- Conditions
- Cardiopulmonary Bypass, Consciousness Monitors, Isoflurane
- Study type
- Observational
- Recruitment status
- Completed
- Enrolment
- 22 participants (actual)
- Lead sponsor
- University of EdinburghUniversity, hospital or other
- Study start
- Apr 2015 (actual)
- Primary completion
- Jan 2019 (actual)
- Study completion
- Jan 2019 (actual)
- First posted
- 15 Jun 2015 (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.
There is no clinical way of assessing the depth of anaesthesia while patients are on the heart-lung machine. A new method of measuring the depth of anaesthesia using brainwaves called the Bispectral index (BIS) has been developed and its use in cardiac surgery is now widespread. However BIS is also altered by patients body temperature. As cooling is common during heart surgery the use of BIS to measure the depth of anaesthesia during heart-lung bypass remains controversial. This study aims to find out what depth of anaesthesia is produced according to BIS during heart lung bypass using a standard anaesthetic technique that utilises the anaesthetic isoflurane.
Detailed description
There is no clinical way of assessing patients' depth of anaesthesia on the heart-lung machine. For this reason, the amount of volatile anaesthetic agent like isoflurane, that is administered has traditionally been determined by anaesthetists' clinical experience. Recently, a device that assesses depth of anaesthesia by analysing the electrical brain waves called the Bispectral index (BIS) has been introduced. The study aims to determine whether the level of anaesthesia produced by isoflurane using the traditional approach is more than required simply to maintain unconsciousness according to BIS. In addition, the study will determine whether the concentration of isoflurane in exhaust gases from the heart-lung machine can be used as an estimate arterial blood concentration and so, depth of anaesthesia.
The study will recruit patients who are scheduled for heart surgery using a heart-lung machine. Patients will be anaesthetised using a long established balanced technique including the administration of isoflurane 2.5% whilst supported on the heart-lung machine. Measurements of exhaust gas concentration of isoflurane from the heart-lung machine and level of BIS will be recorded at three time points. Simultaneously, three arterial blood samples will be taken and the isoflurane concentration measured in these samples. The BIS levels will be averaged and the proportion of patients with a BIS below 40 (lower limit of normal) will be calculated. Concentrations of isoflurane in the exhaust gas of the heart-lung machine will be compared with blood concentrations of isoflurane and the both concentrations will be compared with the level of BIS to establish whether they can be used to assess depth of anaesthesia.
If this study finds that a large proportion of patients have more than adequate levels of anaesthesia, then future studies could explore whether administering lower concentrations of isoflurane improves outcome whilst maintaining anaesthesia.
Study design
- Observational model
- Cohort
- Time perspective
- Prospective
- Number of arms
- 1
| Arm | Type | Receives |
|---|---|---|
| Elective Cardiac surgery | – | Procedure: 2.5 % Isoflurane administrationThose patients scheduled for elective heart surgery requiring cardiopulmonary bypass who will be given 2.5% isoflurane while on bypass. |
Who may qualify
- Ages
- 18 years and older
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
- Study population
- Those patients scheduled for elective heart surgery over the age of 18 requiring cardiopulmonary bypass
Key inclusion criteria (3 listed)
- Participants over the age of 18
- Scheduled for elective cardiac surgery under the care of trial anaesthetists
- Patient has provided informed consent to participate
Key exclusion criteria (5 listed)
- Patients presenting for emergency cardiac surgery
- Patients who will have cardiac surgery that does not require cardiopulmonary bypass
- Unwilling/unable to provide informed consent
- Patients under the age of 18
- Anaesthesia undertaken by anaesthetists not involved in trial
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 |
|---|---|---|
| 2.5 % Isoflurane administrationAnaesthesia maintained during cardiopulmonary bypass with 2.5% isoflurane administered via the oxygenator of the bypass circuit. | Procedure or surgery | Elective Cardiac surgery |
Primary outcome
Depth of anesthesia according to BIS
Time frame: Intraoperative
BIS reading will be recorded at three time points during cardiopulmonary bypass
3 secondary outcomes
Comparison of exhaust gas and blood concentration of isoflurane
Time frame: Intraoperative
Comparison of blood isoflurane concentration and BIS score
Time frame: Intraoperative
Comparison of exhaust isoflurane Concentration and BIS score
Time frame: Intraoperative
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 21 Jun 2021.
- Results publication: PubMed 30638148Alston RP, Connelly M, MacKenzie C, Just G, Homer N. The depth of anaesthesia associated with the administration of isoflurane 2.5% during cardiopulmonary bypass. Perfusion. 2019 Jul;34(5):392-398. doi: 10.1177/0267659118822946. Epub 2019 Jan 12.
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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.
Peter Alston, MBChB principal investigator
University of Edinburgh
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
An observational study of Cardiopulmonary Bypass and Consciousness Monitors, run by University of Edinburgh at 1 site in United Kingdom.
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 5 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 21 Jun 2021. 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 Kingdom. 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.
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?
Depth of anesthesia according to BIS (time frame: Intraoperative). 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 NCT02471950, which also lists 1 linked publication.
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 21 Jun 2021; AzTrials last refreshed its copy on 31 Oct 2026.