Assessment of Brain Oxygen Drops During Surgery and Related Risk Factors for Cognitive Problems After Heart Surgery

January 24, 2026 updated by: ŞULE BALK, Bursa Yuksek Ihtisas Training and Research Hospital

Evaluation of Intraoperative Cerebral Desaturation and Risk Factors Associated With Cognitive Dysfunction After Cardiac Surgery

This study examines whether decreases in brain oxygen levels during cardiac surgery are linked to postoperative cognitive dysfunction and identifies other factors that may increase the risk of cognitive impairment.

Study Overview

Status

Completed

Conditions

Detailed Description

In this prospective study, the relationship between intraoperative cerebral oxygen saturation and postoperative cognitive dysfunction (POCD) was investigated in adult patients undergoing elective cardiac surgery with cardiopulmonary bypass (CPB). Patients with a preoperative Mini-Mental State Examination (MMSE) score ≥ 24, no history of cerebrovascular disease, and no conditions that could interfere with near-infrared spectroscopy (NIRS) monitoring were included.

Measurements were recorded at the following time points: T0 (before induction), T1 (15 minutes after induction), T2 (5 minutes after initiation of CPB), T3 (during the hypothermic phase of CPB), T4 (rewarming phase of CPB, at 34 °C), T5 (termination of CPB), and T6 (upon admission to the intensive care unit). Patients were divided into two groups according to postoperative cognitive outcomes: those who developed POCD and those who did not.

Cognitive function was assessed using the MMSE preoperatively and on postoperative days 4, 7, and 30. During surgery, cerebral oxygen saturation was measured at predefined time points using NIRS probes placed on the frontal region, and detailed intraoperative and perioperative data were recorded. Standardized interventions were implemented when a decrease of more than 20% in regional cerebral oxygen saturation (rSO₂) from baseline was detected in order to maintain adequate cerebral oxygenation.

Study Type

Observational

Enrollment (Actual)

102

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

  • Turkey (Türkiye)
      • Bursa, Turkey (Türkiye), 16000
        • Bursa Yuksek Ihtisas Traning and Research Hospital

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

  • Adult
  • Older Adult

Accepts Healthy Volunteers

No

Sampling Method

Probability Sample

Study Population

Patients undergoing open heart surgery with cardiopulmonary bypass under general anesthesia

Description

Inclusion Criteria:

  • Planned elective CPB surgery
  • Provision of written informed consent
  • Absence of communication barriers that could interfere with preoperative and postoperative MMSE assessment
  • No history of cerebrovascular disease
  • Preoperative MMSE score ≥24
  • Education level of at least high school
  • Absence of any frontal deformity that could hinder NIRS monitoring

Exclusion Criteria:

  • Preoperative use of antipsychotic or antidepressant medications
  • Emergency cardiac surgery indication
  • Presence of ≥50% carotid artery stenosis

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 POCD: Patients develop cognitive dysfunction after cardiac surgery
The POCD group (n=24) comprised patients undergoing elective cardiac surgery with cardiopulmonary bypass who developed postoperative cognitive dysfunction, defined as an MMSE score ≤23 at any postoperative assessment. ( Postoperative day 4 ,7, 30)
Group non-POCD : Patients did not develop postoperative cognitive dysfunction
The non-POCD group (n = 50) consisted of adult patients undergoing elective cardiac surgery with cardiopulmonary bypass whose MMSE scores remained ≥24 at all postoperative assessments, indicating no postoperative cognitive dysfunction.

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Incidence of Postoperative Cognitive Dysfunction (POCD)
Time Frame: Baseline (preoperative, before surgery) and postoperative day 4, postoperative day 7, and postoperative day 30.
Postoperative cognitive dysfunction (POCD) is defined as a decline in cognitive performance assessed using the Mini-Mental State Examination (MMSE), with a score of ≤23 at any postoperative assessment compared with a preoperative baseline MMSE score of ≥24. This primary outcome evaluates the association between intraoperative cerebral oxygen desaturation, measured by near-infrared spectroscopy (NIRS) as a reduction of >20% from baseline regional cerebral oxygen saturation (rSO₂), and postoperative cognitive dysfunction following cardiac surgery with cardiopulmonary bypass.
Baseline (preoperative, before surgery) and postoperative day 4, postoperative day 7, and postoperative day 30.

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Intraoperative Cerebral Oxygen Desaturation Measured by NIRS
Time Frame: Perioperatively (during surgery) through immediate postoperative period (upon ICU admission).

Magnitude of intraoperative decreases in regional cerebral oxygen saturation (rSO₂) relative to baseline, measured using near-infrared spectroscopy (NIRS) at predefined intraoperative time points.

Measurements are recorded at:

T0: before induction of anesthesia T1: 15 minutes after induction of anesthesia T2: 5 minutes after initiation of cardiopulmonary bypass (CPB) T3: hypothermic phase of CPB T4: rewarming phase of CPB (34 °C) T5: weaning from CPB T6: upon admission to the intensive care unit (ICU)
Perioperatively (during surgery) through immediate postoperative period (upon ICU admission).
Postoperative Cognitive Performance Over Time Assessed by MMSE
Time Frame: Baseline (preoperative, before surgery) and postoperative day 4, postoperative day 7, and postoperative day 30.
Changes in cognitive performance over time assessed using the Mini-Mental State Examination (MMSE) to evaluate early and late postoperative cognitive recovery.
Baseline (preoperative, before surgery) and postoperative day 4, postoperative day 7, and postoperative day 30.
Operation Time
Time Frame: From skin incision to skin closure during surgery

Operation time will be compared between patients with and without postoperative cognitive dysfunction (POCD).

Measure : Minute
From skin incision to skin closure during surgery
Cardiopulmonary Bypass (CPB) Duration
Time Frame: From initiation to termination of cardiopulmonary bypass during surgery (single intraoperative assessment).

Cardiopulmonary bypass duration will be compared between patients with and without postoperative cognitive dysfunction (POCD).

Measure : Minute
From initiation to termination of cardiopulmonary bypass during surgery (single intraoperative assessment).
Aortic Cross-Clamp (ACC) Duration
Time Frame: From application to removal of the aortic cross-clamp during surgery (single intraoperative assessment)

Aortic cross-clamp duration will be compared between patients with and without postoperative cognitive dysfunction (POCD).

Meusure: Minute
From application to removal of the aortic cross-clamp during surgery (single intraoperative assessment)
Time to Extubation
Time Frame: From completion of surgery until successful extubation, assessed up to 30 postoperative days

Time to extubation will be compared between patients with and without postoperative cognitive dysfunction (POCD).

Measure: Hour
From completion of surgery until successful extubation, assessed up to 30 postoperative days
Intensive Care Unit Length of Stay
Time Frame: From ICU admission after surgery until ICU discharge, assessed up to 30 postoperative days.

Length of intensive care unit stay will be compared between patients with and without postoperative cognitive dysfunction (POCD).

Measure: Hour
From ICU admission after surgery until ICU discharge, assessed up to 30 postoperative days.
Hospital Length of Stay
Time Frame: From hospital admission for cardiac surgery until hospital discharge, assessed up to 30 postoperative days.

Hospital length of stay will be compared between patients with and without postoperative cognitive dysfunction (POCD).

Measure: Day
From hospital admission for cardiac surgery until hospital discharge, assessed up to 30 postoperative days.
Correlation Between Perioperative Clinical Variables and Postoperative MMSE Scores
Time Frame: Postoperative day 4, postoperative day 7, and postoperative day 30.
Correlation between perioperative clinical variables and postoperative cognitive performance assessed using the Mini-Mental State Examination (MMSE). Variables correlated with MMSE scores include: Operation time (minutes) Cardiopulmonary bypass (CPB) duration (minutes) Aortic cross-clamp (ACC) duration (minutes) Intensive care unit (ICU) length of stay (hours) Hospital length of stay (days)
Postoperative day 4, postoperative day 7, and postoperative day 30.

Collaborators and Investigators

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

Sponsor

Bursa Yuksek Ihtisas Training and Research Hospital

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)

March 1, 2023

Primary Completion (Actual)

March 1, 2024

Study Completion (Actual)

March 25, 2024

Study Registration Dates

First Submitted

December 22, 2025

First Submitted That Met QC Criteria

January 14, 2026

First Posted (Actual)

January 22, 2026

Study Record Updates

Last Update Posted (Actual)

January 27, 2026

Last Update Submitted That Met QC Criteria

January 24, 2026

Last Verified

January 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • 011-KAEK-25 2023/02-15

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

UNDECIDED

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.

Clinical Trials on Cognitive Dysfunction

Search Similar Trials

Sponsors and Collaborators

Medical Conditions

Drug Interventions

CROs by country

CROs in Mauritania

Conditions

Rare Diseases

Drug Interventions

Dietary Supplements

Sponsor/Collaborators

Locations

Subscribe