Effects of Transcutaneous Vagal Nerve Stimulation on Post-Surgical Return to Consciousness, Delirium, and Depression

Time in minutes to a Patient State Index (PSI) (Sedline Sedation Monitor) score of 85. The PSI is a quantitative score derived from 4 channel EEG monitoring of the frontal and prefrontal cortex for assessing level of consciousnes during sedation and general anesthesia. The score ranges from 0 (EEG supression) -100 (fully awake). A PSI range of 25-50 indicates optimal hypnotic state for general anesthesia

The Richmond Agitation-Sedation Scale (RASS) is a 10-point validated scale used to measure patient sedation levels in post-anesthesia care unit, ranging from +4 (combative) to -5 (unarousable). A score of 0 is "alert and calm".Measured on arrival to PACU then at 10,15,30,45,60 minutes after admission to PACU.

Admission time to the PACU to discharge from PACU in minutes elapsed.

Time from Post Anesthesia Care Unit discharge to discharge from the hospital in days/minutes

Comparison between active and sham tcVNS on delirium scores in the PACU at 30, 45 and 60 minutes after admission to the PACU. The 3D Confusion Assessment Method (3D CAM) will be administered at 30, 45 and 60 minutes after admission to PACU. The 3D CAM diagnostic tool scores delirium based on four core features, where Feature 1 (Acute Change) AND Feature 2 (Inattention) MUST be present, plus either Feature 3 (Disorganized Thinking) or Feature 4 (Altered Consciousness). It offers a severity score (3D-CAM-S) ranging from 0-20, with higher scores indicating more severe symptoms (0/20 low 20/20 high

Delirium scores 30 days after discharge from the hospital. The 3D Confusion Assessment Method (3D CAM) will be administered 30 days after discharge from the hospital. The 3D CAM diagnostic tool scores delirium based on four core features, where Feature 1 (Acute Change) AND Feature 2 (Inattention) MUST be present, plus either Feature 3 (Disorganized Thinking) or Feature 4 (Altered Consciousness). It offers a severity score (3D-CAM-S) ranging from 0-20, with higher scores indicating more severe symptoms (0/20 low 20/20 high

The Patient Health Questionnaire Nine (PHQ-9) is a 9-question survey used to measure patient depression potential, ranging 1-27 (1 low possibility of depression to 27 highest potential for depression. Tested at baseline, post operative day 1 and 30 days post discharge from hospital.

Continuous EEG monitoring data to be evaluated for patterns associated with delirium (polymorphiic delta waves, generalized slowing quantified as delta range vs alpha range power

The MoCA includes measures of memory recll, visuospatial processing, executive functions, attention, language, abstract reasoning and orientation to time and place. Administered baseline and post operative day 2. 0-30 point scale, 26 and above is normal, 18-25 mild cognitive dysfunction, 10-17 is moderate dysfunction and 0-10 is severe dysfunction.

The 36-Item Short Form Survey (SF-36) is a self-reported patient outcome measure that assesses physical and mental health across eight domains, including functioning, pain, and vitality. Score ranges from 0 low to 100 high. The higher the score the better the overall health. Administered at baseline and 30 days after discharge.

This is a brief self-report tool used to measure perceived difficulties in everyday cognitive tasks. It is a portion of of the Quality of Life in Neurological Disorders (Neuro-QoL). he short form uses T-scores, which standardize results against a reference population (typically the U.S. general population).There are 8 questions. A T-score of 50 represents the average for the reference population. A high score indicates better perceived cognitive function. Completed at baseline and 30 days.

Neuro-QoL(Quality of Life in Neurological Disorders) is a measurement system that evaluates and monitors the physical, mental, and social effects experienced by adults who may have neurological conditions. Tested at baseline and 30 days.

The Delirium Rating Scale (DRS-R-98) is a tool for assessing symptom severity and diagnosing delirium in clinical settings. This sixteen-item scale in a thirteen-item severity section and three diagnostic items, tracking changes over a twenty-four-hour period. The 16-item, clinician-rated tool used to diagnose and measure the severity of delirium. It consists of 13 severity items (scored 0-3) and 3 diagnostic items (scored 0-2 or 0-3), with a maximum total score of 46. Higher scores indicate more severe delirium, with scores of15 or greater than or greater than 17.5 often indicating delirium. Assessed at Day 1 and day 2 post operative.

Digit Span test measures auditory short-term memory and working memory capacity by asking participants to repeat sequences of digits in forward, reversed, or ordered sequences. It is used to measure cognitive processing, attention, and executive function, usually contains 5-9 digits. scoring typically awards one point for each correctly repeated sequence. Performed post operative day 1and 2.