An MRI Study of Post-operative Delirium in Patients Undergoing Major Surgery

July 9, 2019 updated by: University of Manitoba

"Blue" Cerebrovascular Reactivity (CVR) Maps as a Marker for Post-operative Delirium (POD) in Patients Undergoing Abdominal Aortic Aneurysm (AAA) Surgery: A Pilot Study: Addition of Other Patients Being Admitted to SSCU After Major Surgery

Hypothesis: Patients with blue cerebrovascular reactivity (CVR) regional maps during a hypercapnic CO2 challenge will be at greater risk of developing post-operative delirium (POD) and stroke following major surgery. Blue CVR maps have also been recently documented with an O2 challenge. The blue CVR maps will be shown to be predictive of POD and stroke and ultimately represent a diagnostic test for patients at risk. These blue CVR maps will enable neurologic risk stratification for patients undergoing major surgery. Background: Major surgery is associated with a significant risk of postoperative morbidity and mortality. POD is a dreaded complication with such anesthesia and surgery. The prevalence of delirium after cardiac surgery has been reported to occur in up to 50% of patients. Using a definitive diagnostic tool such as the Confusion Assessment Method - Intensive Care Unit (CAM-ICU and CAM-S) results in the higher proportion reported. Delirium is a serious complication that results in prolonged length of stay, increased health care costs, and higher mortality. As much as $6.9 billion of Medicare hospital expenditures can be attributed to delirium. At such a cost, better diagnosis and treatment is urgently needed. Pre-emptive diagnosis leading to better management of delirium post-operatively is clearly one of the fundamental problems confronting modern anesthesia and peri-operative medicine.

Specific Objectives: The investigators seek to address (a) the identity of patients who have the greatest vulnerability to the surgery and (b) investigate the risks and test appropriate risk mitigations. Understanding POD is of immense import to help control a hospital's surgical and critical care costs. Patients with neurological consequences including POD often represent a choke point for optimized critical care utilization. At the very least, improved understanding and a diagnostic test to highlight patients at risk of POD would be most welcome. Such an advance would permit rational strategies to limit the problem and allow better designed therapeutic arcs for patients now known to be at risk. This is especially important for patients undergoing complicated major surgery and is the focus of this pilot project. Tighter control of ET respiratory gases may be indicated for both ET CO2 and ET O2 based on the results of this preliminary study.

Study Overview

Status

Unknown

Conditions

Intervention / Treatment

Detailed Description

Methods: Informed witnessed consent will be obtained from all participants. Patients will have a Mini Mental State Exam (MMSE) prior to their MRI studies. A battery of neurocognitive tests will be undertaken for each subject prior to surgery. This test battery will include PHQ-9, GAD-7, Trails A and WAIS-IV Digit Span, Hopkins Verbal Learning Test Revised, Rey's Complex Figure, DKEFS, F-A-S, CLOX I and II. This will take 45-60 minutes. Patients will have CVR maps with blood oxygen level dependent (BOLD-MRI) pulse sequences done with standard RespirAct (a computer-controlled gas blender) protocols in association with anatomic imaging in a 3.0 Tesla magnet. The clinical care team and patient will be blinded as to the CVR results. Patients will have standardized anesthesia and per usual approaches for their major surgery and have standard POD assessment tools (CAM-ICU and CAM-S). Storage of anesthesia hemodynamics will be to digital data acquisition systems for later collation. End-tidal CO2 will be targeted at patient baseline values +/- 2.5 mmHg during the surgical procedure and if ventilated for any period post-operatively. Inspired O2 will be targeted to 0.3 - 0.6, based on pulse oximetry of greater than 95% with adequate arterial oxygenation confirmed by ABG. Standard fast-track protocols and admission to the surgical special care unit (SSCU) will be undertaken to facilitate patient management. Any patient with obvious POD, post-op delirium or stroke will be managed per usual protocols. Multiple CVR maps (650 studies) have been done at University Health Network in Toronto. As well over 150 studies have been conducted at the Health Sciences Centre at the University of Manitoba in the past 5 years.

Significance/Importance: This study has the potential to make an important contribution in the understanding of POD for all surgical procedures and specifically a window into the problem with major surgery. A positive study based on our hypothesis can fundamentally change our understanding of cognitive dysfunction after surgery. Large follow-up multicentre trials can be constructed based on initial findings from this pilot study if the study bears fruit. At the least, further elucidation into POD for major surgery is expected with this study. tighter control of end-tidal gases may be a consequence of the findings of this study.

Study Type

Observational

Enrollment (Anticipated)

20

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

  • Canada
    • Manitoba
      • Winnipeg, Manitoba, Canada, R3E 0Z2
        • Recruiting
        • Kleysen Institute for Advanced Medicine - Health Sciences Centre
        • Contact:
        • Contact:
        • Principal Investigator:
          • W. Alan Mutch, MD

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

Ages Eligible for Study

18 years to 80 years (Adult, Older Adult)

Accepts Healthy Volunteers

No

Genders Eligible for Study

All

Sampling Method

Non-Probability Sample

Study Population

Patients scheduled to undergo major surgery.

Description

Inclusion Criteria:

  • major surgery
  • able to tolerate CO2 and O2 stress test

Exclusion Criteria:

  • diagnosed dementia
  • unable to have MRI
  • excessive claustrophobia
  • unstable angina, recent myocardial infarction (MI)
  • chronic obstructive pulmonary disease (COPD)

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

  • Observational Models: Case-Only
  • Time Perspectives: Prospective

Cohorts and Interventions

Group / Cohort
Intervention / Treatment
Study group - MRI CO2 and O2 stress test
This is a pilot study to assess feasibility of using MRI CO2 and O2 stress testing to predict POD.
Procedure: MRI CO2 and O2 stress testing
Pre and post operatively

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Blue voxel count/whole brain voxel count
Time Frame: Baseline
the number and distribution of 'blue' voxels - those with reversed CO2 and O2 responsiveness to a controlled CO2 and O2 change with blood oxygen level dependent (BOLD) MRI.
Baseline
Incidence of post-op delirium
Time Frame: Post-op out to discharge or maximum of 2 weeks post-surgery
the incidence and severity of post-op delirium using the cognitive assessment method - intensive care unit (CAM-ICU) scoring approach twice a day.
Post-op out to discharge or maximum of 2 weeks post-surgery

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Length of Stay (LOS) in hospital
Time Frame: post-operatively to 2 weeks
Length of stay in hospital - number of days from day of surgery up to a maximum of 2 weeks.
post-operatively to 2 weeks
Stroke
Time Frame: Post-op until time of discharge up to 2 weeks
Post-op stroke rate and severity will be assessed.
Post-op until time of discharge up to 2 weeks
Intra-operative blood pressure
Time Frame: Intra-operative
Blood pressure will be measured in mmHg at 60 hz. during the operative procedure. The nadir and time below 60 mmHg will be recorded.
Intra-operative

Other Outcome Measures

Outcome Measure
Time Frame
Pre-op test for post-operative delirium (POD)
Time Frame: up to 2 weeks
up to 2 weeks

Collaborators and Investigators

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

Sponsor

University of Manitoba

Investigators

  • Principal Investigator: W. Alan Mutch, MD, University of Manitoba

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

July 1, 2014

Primary Completion (Anticipated)

July 1, 2020

Study Completion (Anticipated)

July 1, 2020

Study Registration Dates

First Submitted

April 22, 2014

First Submitted That Met QC Criteria

April 28, 2014

First Posted (Estimate)

April 29, 2014

Study Record Updates

Last Update Posted (Actual)

July 11, 2019

Last Update Submitted That Met QC Criteria

July 9, 2019

Last Verified

July 1, 2019

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • B2013:057-AAA

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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