Isoflurane During Cardiopulmonary Bypass

June 18, 2021 updated by: University of Edinburgh

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.

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Completed

Conditions

Conditions

The disease, disorder, syndrome, illness, or injury that is being studied. On ClinicalTrials.gov, conditions may also include other health-related issues, such as lifespan, quality of life, and health risks.

Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.

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 Type

Study Type

Describes the nature of a clinical study. Study types include interventional studies (also called clinical trials), observational studies (including patient registries), and expanded access.
Observational

Enrollment (Actual)

Enrollment

The number of participants in a clinical study. The "anticipated" enrollment is the target number of participants that the researchers need for the study.
22

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

  • United Kingdom
    • Scotland
      • Edinburgh, Scotland, United Kingdom, EH16 4SA
        • Royal Infirmary of Edinburgh

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Eligibility Criteria

The key requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria (which are required for a person to participate in the study) and exclusion criteria (which prevent a person from participating). Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

Ages Eligible for Study

18 years and older (Adult, Older Adult)

Accepts Healthy Volunteers

No

Genders Eligible for Study

All

Sampling Method

Non-Probability Sample

Study Population

Those patients scheduled for elective heart surgery over the age of 18 requiring cardiopulmonary bypass

Description

Inclusion Criteria:

  • Participants over the age of 18
  • Scheduled for elective cardiac surgery under the care of trial anaesthetists
  • Patient has provided informed consent to participate

Exclusion Criteria:

  • 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

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

Cohorts and Interventions

Group / Cohort

Group / Cohort

A group or subgroup of participants in an observational study that is assessed for biomedical or health outcomes.
Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.
Elective Cardiac surgery
Those patients scheduled for elective heart surgery requiring cardiopulmonary bypass who will be given 2.5% isoflurane while on bypass.
Procedure: 2.5 % Isoflurane administration
Anaesthesia maintained during cardiopulmonary bypass with 2.5% isoflurane administered via the oxygenator of the bypass circuit.

What is the study measuring?

Primary Outcome Measures

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
Outcome Measure
Measure Description
Time Frame
Depth of anesthesia according to BIS
Time Frame: Intraoperative
BIS reading will be recorded at three time points during cardiopulmonary bypass
Intraoperative

Secondary Outcome Measures

Secondary Outcome Measures

In a clinical study's protocol, a planned outcome measure that is not as important as the primary outcome measure for evaluating the effect of an intervention but is still of interest. Most clinical studies have more than one secondary outcome measure.
Outcome Measure
Measure Description
Time Frame
Comparison of exhaust gas and blood concentration of isoflurane
Time Frame: Intraoperative
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.
Intraoperative
Comparison of blood isoflurane concentration and BIS score
Time Frame: Intraoperative
Blood isoflurane concentration and BIS will be recorded at three time points and compared to see if they are related
Intraoperative
Comparison of exhaust isoflurane Concentration and BIS score
Time Frame: Intraoperative
Exhaust isoflurane and BIS will be recorded at three time points and compared to see they are related.
Intraoperative

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
University of Edinburgh

Investigators

Investigators

A researcher involved in a clinical study. Related terms include site principal investigator, site sub-investigator, study chair, study director, and study principal investigator.
  • Principal Investigator: Peter Alston, MBChB, University of Edinburgh

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
April 1, 2015

Primary Completion (Actual)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
January 1, 2019

Study Completion (Actual)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
January 1, 2019

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
June 1, 2015

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
June 10, 2015

First Posted (Estimate)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
June 15, 2015

Study Record Updates

Last Update Posted (Actual)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
June 21, 2021

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
June 18, 2021

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
June 1, 2021

More Information

Terms related to this study

Additional Relevant MeSH Terms

Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant numbers.
  • 15 LO 0366
  • 2015/0199 (Other Identifier: NHS Lothian)

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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