Cerebral Blood Supply During Cardiopulmonary Bypass

March 5, 2019 updated by: Ulrike Weber, Medical University of Vienna

Influence of Cerebral Blood Supply During Cardiopulmonary Bypass on the Incidence of Postoperative Delirium in Open-heart Surgery

Postoperative delirium is an acute and fluctuating state of confusion and disorientation with an incidence of 25-70% after cardiac surgery. Possible reasons for this multifactorial complication are hypoperfusion, cerebral microembolization and inflammatory response, which eventually lead to regional or global imbalance between cerebral oxygen demand and supply. Adequate cerebral blood supply depends sufficient blood supply via the vertebral arteries and the internal carotid arteries. The aim of this preliminary study is to investigate if patients who develop delirium after open-heart surgery show differences in their cerebral blood flow during cardiopulmonary bypass (CPB) in extracerebral arterial vessels compared to those patients without delirium.

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

Postoperative delirium is an acute and fluctuating state of confusion and disorientation, characterized by changes in attention, cognition, consciousness, and perception, with an incidence of 25-70% after cardiac surgery. Possible reasons for this multifactorial complication are hypoperfusion, cerebral microembolization and inflammatory response, which eventually lead to regional or global imbalance between cerebral oxygen demand and supply. This frequent cerebral injury has detrimental and long-lasting consequences and remains a serious healthcare burden, particularly due to its association with higher medical costs, increased morbidity, long-term cognitive deficits, and greater mortality. Progress in reducing the incidence of delirium has been hindered by the lack of a full understanding of its pathophysiology.

Adequate cerebral blood supply depends sufficient blood supply via the vertebral arteries and the internal carotid arteries. Whereby the blood supply of the brain by the carotid arteries is two-thirds and is easily accessable for blood flow examination with Doppler ultrasound.

The aim of this preliminary study is to investigate if patients who develop delirium after open-heart surgery show differences in their cerebral blood flow during cardiopulmonary bypass (CPB) in extracerebral arterial vessels compared to those patients without delirium. Additionally we want to investigate the influence of cerebral microembolisation and CPB associated inflammation in those patients. As secondary outcome measure we also want to determine differences in length of stay (LOS) in the intensive care unit (ICU) as well as in hospital LOS and 30-day mortality.

Methods:

Design:

Prospective observational study

Population:

Elective cardiac surgical patients undergoing valve replacement/reconstruction surgery on cardiopulmonary bypass.

Procedure:

Patients will be enrolled the day before surgery by one physician of the study group.

Anaesthesia will be induced with propofol (1.0-1.5 mg/kg), fentanyl (3-10 μg/kg), and cisatracurium (0.2 mg/kg). It will be maintained with sevoflurane (target BIS value 40-50) 11, and fentanyl (0.05-0.1 μg/kg/min). Patients will receive tranexamic acid (10 mg/kg after anaesthesia induction plus the same dosage in the CPB prime), depending on their kidney function.

Anticoagulation will be achieved with heparin (400 IE/kg) to an activated clotting time (ACT) >400 s.

CPB will be performed using non-pulsatile target flow of 100% calculated cardiac output. Mean arterial pressure will be maintained between 60 to 70 mmHg throughout CPB.

To standardize the intraoperative course of our patients we will limit the intraoperative haematocrit to 22% and the PaCO2-concentration between 30 and 40 mmHg.12 Blood glucose levels will be held between 80-150 mg/dl intra- and postoperatively. Sedation on ICU will be performed using propofol until extubation

Carotis duplex sonography for perfusion flow will be evaluated at the following timepoints:

  1. Before induction of anaesthesia
  2. Before going on CBP
  3. During CPB, 5 min after aortic cross clamping
  4. After CPB
  5. 24 hours after CPB Blood flow will be derived from the product of the vessels' cross-sectional area and the intensity-weighted mean blood flow velocity through the vessel using a pulsed-wave Doppler in ml/min. Because the sample volume will be adjusted to the width of the vessel at the point where the diameter width will be measured, the measurement can be performed independent of flow conditions (laminary or pulsatile). Imaging of the vessel will be performed in the longitudinal plane, the cross-sectional area will be assumed to be circular.

To diagnose postoperative delirium two delirium assessement tests will be used:

  • Confusion Assessment method for the ICU (CAM-ICU) and
  • The Intensive Care Delirium Screening Checklist (ICDSC)

Delirium Scores will be measured at the following timepoints:

  1. Postoperative day (POD) 1
  2. POD 2
  3. POD 5

The CAM-ICU will be assessed twice a day (in the morning and in the evening). The Confusion Assessment Method (CAM) will be performed after discharge from the ICU.

Transcranial Doppler ultrasound (TCD) for detection and differentiation of high-intensity transient signals (HITS) in both middle cerebral arteries (MCAs) into artefacts, solid, and gaseous cerebral microemboli (CME) will be performed at the following timepoints:

  1. During cannulation of the ascending aorta
  2. After aortic cross-clamp
  3. During decannulation All collected data will be saved password-protected in an electronic database on the department's server after data collection has been finished. Only studyteam-members will have access to this data. After completion of the study the results are to be published according to GCP-standards.

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.
40

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

  • Austria
      • Vienna, Austria, 1090
        • Medical university of vienna, General hospital of Vienna

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 to 100 years (ADULT, OLDER_ADULT)

Accepts Healthy Volunteers

No

Genders Eligible for Study

All

Sampling Method

Probability Sample

Study Population

Elective cardiac surgical patients undergoing valve replacement/reconstruction surgery on cardiopulmonary bypass.

Description

Inclusion Criteria:

elective cardiac surgery valve replacement/reconstruction cardiopulmonary bypass

Exclusion Criteria:

  • Emergency procedures
  • Postoperative need for extracorporal cardiac assist device
  • Untreated or uncontrolled arterial hypertension
  • Profound hypothermic CPB (body temperature <34°C)
  • History of preoperative dementia
  • History of Stroke
  • Significant carotid artery stenosis
  • Age < 18 years
  • Chronic renal replacement therapy
  • Declined informed consent

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.
Delirium
patients who develop postoperative delirium after surgery with cardiopulmonary bypass measured by Delirium scores (CAM-ICU, ICDSC), TCD for detection of HITS and carotis duplex sonography
Diagnostic test: Delirium Scores
  • Confusion Assessment method for the ICU (CAM-ICU) and
  • The Intensive Care Delirium Screening Checklist (ICDSC)

Delirium Scores will be measured at the following timepoints:

  1. Postoperative day (POD) 1
  2. POD 2
  3. POD 5
Diagnostic test: Carotis duplex sonography

Carotis duplex sonography for perfusion flow will be evaluated at the following timepoints:

  1. Before induction of anaesthesia
  2. Before going on cardiopulmonary bypass (CBP)
  3. During CPB, 5 min after aortic cross clamping
  4. After CPB
  5. 24 hours after CPB
Diagnostic test: TCD for detection of HITS

Transcranial Doppler ultrasound (TCD) for detection and differentiation of high-intensity transient signals (HITS) in both middle cerebral arteries (MCAs) into artefacts, solid, and gaseous cerebral microemboli (CME) will be performed at the following timepoints:

  1. During cannulation of the ascending aorta
  2. After aortic cross-clamp
  3. After opening of the aortic cross-clamp
  4. During decannulation
No delirium
patients who develop no postoperative delirium after surgery with cardiopulmonary bypass measured by delirium scores (CAM-ICU, ICDSC), TCD for detection of HITS and carotis duplex sonography
Diagnostic test: Delirium Scores
  • Confusion Assessment method for the ICU (CAM-ICU) and
  • The Intensive Care Delirium Screening Checklist (ICDSC)

Delirium Scores will be measured at the following timepoints:

  1. Postoperative day (POD) 1
  2. POD 2
  3. POD 5
Diagnostic test: Carotis duplex sonography

Carotis duplex sonography for perfusion flow will be evaluated at the following timepoints:

  1. Before induction of anaesthesia
  2. Before going on cardiopulmonary bypass (CBP)
  3. During CPB, 5 min after aortic cross clamping
  4. After CPB
  5. 24 hours after CPB
Diagnostic test: TCD for detection of HITS

Transcranial Doppler ultrasound (TCD) for detection and differentiation of high-intensity transient signals (HITS) in both middle cerebral arteries (MCAs) into artefacts, solid, and gaseous cerebral microemboli (CME) will be performed at the following timepoints:

  1. During cannulation of the ascending aorta
  2. After aortic cross-clamp
  3. After opening of the aortic cross-clamp
  4. During decannulation

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
cerebral blood flow
Time Frame: during surgery
Differences in mean laminar cerebral blood flow on cardiopulmonary bypass during open heart surgery between patients with and without postoperative delirium
during surgery

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
HITS (high-intensity transient signals)
Time Frame: during surgery
Difference in the number and quality of HITS measured with transcranial Doppler ultrasound between patients with and without delirium
during surgery

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.
Medical University of Vienna

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.
May 1, 2017

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.
June 30, 2018

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.
December 31, 2018

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).
April 6, 2017

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.
April 12, 2017

First Posted (ACTUAL)

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.
April 18, 2017

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.
March 6, 2019

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.
March 5, 2019

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.
March 1, 2019

More Information

Terms related to this study

Keywords

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.
  • 1964/2016

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

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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