Elderly Patients Undergoing Surgery During Perioperative Period

POD is diagnosed daily using the Three-Minute Diagnostic Confusion Assessment Method (3D-CAM).

The type of delirium is assessed using the Richmond Agitation-Sedation Scale (RASS). The Richmond Agitation-Sedation Scale (RASS) is a 10-point scale ranging from -5 (unarousable) to +4 (combative). A score of +4 represents a combative state where the patient is violent and poses immediate danger, while a score of -5 indicates no response to any stimulus. Based on the RASS score, delirium can be categorized into three motoric subtypes: Hyperactive delirium: RASS scores consistently between +1 and +4. Hypoactive delirium: RASS scores consistently between 0 and -3. Mixed-type delirium: RASS scores that fluctuate between positive and negative values over the observation period.

The severity of postoperative delirium will be assessed using the Confusion Assessment Method-Severity scale (CAM-S).

Duration is defined as the number of days from the onset of delirium symptoms to symptom resolution or hospital discharge, whichever occurs first.

Neurocognitive decline is assessed by comparing baseline to postoperative scores on: Mini-Mental State Examination (MMSE, 0-30, higher=better function), Montreal Cognitive Assessment (MoCA, 0-30, higher=better function); and five neuropsychological tests-Clock Drawing Test, (DST, 0-16, higher=better attention), Trail Making Test Parts A and B (TMT-A/B, seconds, lower=better), Boston Naming Test (BNT, 0-30, higher=better naming), Auditory Verbal Learning Test - Huashan version (AVLT-H delayed recall, 0-10, higher=better memory), and Clock Drawing Test (CDT, 0-10, higher=better visuospatial/executive function). Patient/caregiver reports are also collected.

Using Visual Analogue Scale (VAS), 0-100, 0 means no pain, 100 means severe pain

The Hospital Anxiety and Depression Scale (HADS) is used for assessment, with each subscale (anxiety or depression) scored from 0-21: "0-7: Non-case", "8-10: Doubtful case", "11-21: Definite case". Higher scores clearly indicate worse outcomes, i.e., more severe anxiety or depression symptoms.

The Activities of Daily Living (ADL) are typically assessed using the Barthel Index. 0-100. A higher score indicates stronger independence: a score of 100 represents complete independence; a score of 61-99 suggests mild functional impairment with basic self-care ability; and a score of ≤40 indicates severe functional impairment, with significant or complete reliance on others for daily living.

Sleep quality is assessed using the Pittsburgh Sleep Quality Index (PSQI). The total score ranges from 0 to 21 points. A score greater than 7 (>7) is typically considered the clinical cutoff for poor sleep quality. A higher score indicates poorer sleep quality.

The FRAIL (Fatigue, Resistance, Ambulation, Illnesses, and Loss of Weight) Scale ranges from 0 to 5. A score of 0 indicates robust/non-frail status, scores of 1-2 indicate pre-frail status, and scores of 3-5 indicate frail status.

using EQ-5D(Score of EuroQol Five Dimensions Questionnaire (EQ-5D)) to measure quality of life

In-hospital mortality; 30-day postoperative mortality; 1-year postoperative mortality

Length of hospital stay are measured from the anesthesia starting day to the discharge day

Hospitalization fees; -Preoperative fees; -Anesthesia fees; -Surgery fees; -Post-operative fees; -Post-discharge medical expenses.