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

Bursa Yuksek Ihtisas Training and Research Hospital102 enrolled

Overview

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.

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

102

Conditions

Cognitive Dysfunction, Postoperative Cognitive Dysfunction Cardiac Surgery

Eligibility

Sex: ALLMin age: 18 Years

Medical Language ↔ Plain English

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

Locations (1)

Bursa Yuksek Ihtisas Traning and Research Hospital

Bursa, Turkey (Türkiye)

Outcomes

Primary Outcomes

Incidence of Postoperative Cognitive Dysfunction (POCD)

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.

Time frame: Baseline (preoperative, before surgery) and postoperative day 4, postoperative day 7, and postoperative day 30.

Secondary Outcomes

Intraoperative Cerebral Oxygen Desaturation Measured by NIRS

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)

Time frame: Perioperatively (during surgery) through immediate postoperative period (upon ICU admission).

Postoperative Cognitive Performance Over Time Assessed by MMSE

Changes in cognitive performance over time assessed using the Mini-Mental State Examination (MMSE) to evaluate early and late postoperative cognitive recovery.

Time frame: Baseline (preoperative, before surgery) and postoperative day 4, postoperative day 7, and postoperative day 30.

Operation Time

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

Data from ClinicalTrials.gov

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