Postoperative delirium (POD) is a common complication in older adults undergoing surgery, lacking objective and noninvasive diagnostic methods. This trial aims to evaluate the feasibility and prognostic performance of Eye movements (EM) as a risk biomarker for the development of POD in older patients undergoing moderate- to high-risk surgery. The investigators hypothesize that EM tracking will accurately predict POD, potentially optimizing early intervention and patient outcomes.
This prospective trial evaluates the integration of automated eye movement assessments as a novel, noninvasive risk biomarker for postoperative delirium (POD) in older adults. Upon enrollment, trained clinical staff will collect baseline demographic data and clinical characteristics. Chronic medical burden will be quantified using the Charlson Comorbidity Index (CCI). To establish baseline cognitive function and control for preexisting cognitive impairment, all participants will undergo the Montreal Cognitive Assessment (MoCA). Technical Protocol for Eye Movement Recording Preoperatively, participants will complete an automated eye movement tracking protocol consisting of two distinct paradigms: Prosaccadic Task: Utilized to measure specific ocular motor parameters, including saccadic latency, velocity, and accuracy. Free Visual Exploration Task: Utilized to capture free-gaze metrics and spatial distribution patterns. All eye-tracking data will be recorded using automated software to ensure objectivity and reproducibility. Postoperative Monitoring Following the surgical procedure, patients will be systematically monitored for the development of POD. The Confusion Assessment Method (CAM) will be administered by trained examiners twice daily (morning and evening) for the first three postoperative days (72 hours) to detect and document the incidence and severity of delirium. Statistical and Predictive Objectives The collected data will be analyzed to fulfill three primary scientific objectives: 1. Parameter Association: To identify which specific preoperative eye-tracking metrics (latency, velocity, accuracy, or free-gaze variables) demonstrate a statistically significant association with the incidence of POD. 2. Diagnostic Performance: To calculate the sensitivity and specificity of these distinct preoperative eye movement parameters for predicting POD development. 3. Incremental Predictive Value: To evaluate whether adding preoperative eye-tracking measurements to a standard clinical prediction model (comprising age, sex, CCI, and MoCA scores) significantly improves the model's overall predictive performance and risk stratification capabilities.
Study Type
OBSERVATIONAL
Enrollment
40
Hospital Clínico de la Universidad de Chile
Santiago, Santiago Metropolitan, Chile
Incidence of postoperative delirium (POD).
The presence or absence of postoperative delirium will be assessed using the Confusion Assessment Method (CAM). Patients will be classified as "POD" or "No POD" based on the CAM diagnostic algorithm.
Time frame: From the day of surgery up to postoperative day 3, patients were assessed twice daily.
Preoperative Baseline Cognitive Status
Total score on the Montreal Cognitive Assessment (MoCA) to determine baseline global cognitive function. The score ranges from 0 to 30, with lower scores indicating greater cognitive impairment.
Time frame: At preoperative baseline (day of surgery or day before).
Preoperative Comorbidity Burden
Score on the Charlson Comorbidity Index (CCI) to quantify the participant's baseline medical comorbidity burden and pre-existing health conditions.
Time frame: At preoperative baseline (day of surgery or day before)
Preoperative Saccadic Latency
The time taken from the appearance of a visual target to the initiation of the participant's saccadic eye movement during the prosaccadic task (milliseconds).
Time frame: At preoperative baseline (day of surgery or day before)
Preoperative Saccadic Velocity
The peak speed of the participant's eye movement when moving towards the visual target during the prosaccadic task (degrees per second).
Time frame: At preoperative baseline (day of surgery or day before).
Preoperative Free Viewing Number of Fixations
The absolute count of discrete gaze fixations made by the participant during the free visual exploration task (number of fixations)
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Time frame: At preoperative baseline (day of surgery or day before).
Preoperative Free Viewing Saccade Length
The average spatial distance between fixations in the participant's eye movements during the free visual exploration task (degrees of visual angle).
Time frame: At preoperative baseline (day of surgery or day before).
Hospital Length of Stay
Total hospital stay from the day of surgery until official hospital discharge.
Time frame: Up to 30 days post-surgery.
All-Cause Mortality
Total number of participant deaths from any cause, verified via hospital electronic medical records or direct follow-up contact.
Time frame: At 30 days post-surgery.