This prospective observational study will evaluate neuro-mimic indicators of anesthesia depth, including eyelid reflex, eyeball movements, and pupil responses, in patients undergoing elective surgery under general anesthesia. Sixty adult patients will be observed at three standardized time points: after induction, during skin incision, and mid-surgery. All parameters will be recorded alongside bispectral index (BIS) monitoring. The study aims to determine whether these observable signs correlate with anesthesia depth, contribute to early detection of intraoperative awareness, and provide a basis for developing non-invasive depth monitoring systems.
Accurate assessment of anesthesia depth is essential to ensure patient safety and reduce the risk of intraoperative awareness. Current technological monitoring tools such as BIS do not always provide sufficient reliability. Neuro-mimic indicators, including eyelid reflex, spontaneous and stimulus-related eye movements, and pupil responses, may offer additional insights into anesthesia depth. This observational, prospective, non-interventional study will enroll 60 adult patients (aged 18-65, ASA I-III) scheduled for elective abdominal surgeries lasting 1-3 hours under general anesthesia at Başakşehir Çam and Sakura City Hospital. Observations will be performed at three intraoperative stages: post-induction, skin incision, and mid-surgery. Parameters include palpebral reflex, eyeball position and movement, and pupil diameter, all systematically documented alongside BIS values. The primary endpoint is the change in pupil diameter across three time points. Secondary outcomes include the presence or absence of eyelid reflex, eye movements, and their correlations with BIS values. Data will be analyzed using repeated measures ANOVA, McNemar test, correlation analyses, and appropriate non-parametric tests where necessary. The study is entirely observational and involves no additional interventions or risks for patients. Results may provide evidence for the integration of observable physiological signs into anesthesia monitoring practice and contribute to the development of contactless depth monitoring systems.
Study Type
OBSERVATIONAL
Enrollment
60
Observation of eyelid reflex, eye movements, and pupil responses at three standardized intraoperative time points (after induction, during skin incision, and mid-surgery). Parameters will be recorded alongside BIS values without any intervention, device application, or additional risk to patients.
Change in pupil diameter during general anesthesia
Pupil diameter (mm) will be measured and compared at three intraoperative stages: after induction and intubation, during skin incision, and mid-surgery. The change over time will be analyzed as an indicator of anesthesia depth.
Time frame: Intraoperative period (observations at induction, incision, and mid-surgery).
Presence or absence of eyelid reflex at different anesthesia stages
Eyelid reflex (palpebral reflex) will be assessed as present or absent at three intraoperative stages and analyzed in relation to anesthesia depth.
Time frame: Intraoperative period (induction, incision, mid-surgery).
Eye position and movements during anesthesia
Eyeball position (central, upward, downward, eccentric) and spontaneous movements will be observed and documented at three time points. Changes will be evaluated as neuro-mimic indicators of anesthesia depth.
Time frame: Intraoperative period (induction, incision, mid-surgery).
Correlation of neuro-mimic indicators with BIS values
Observed eyelid reflex, eye movements, and pupil responses will be correlated with simultaneously recorded BIS values to explore associations with anesthesia depth.
Time frame: Intraoperative period (induction, incision, mid-surgery).
Early indicators of intraoperative awareness
The relationship between observed neuro-mimic responses (eyelid reflex, eye movements, pupil diameter) and intraoperative awareness risk will be evaluated descriptively.
Time frame: Intraoperative period.
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