Effects of Preoperative Sleep Disorders on Perioperative Anesthesia Depth and Recovery Quality in Patients Undergoing Noncardiac Surgery

General Hospital of Ningxia Medical University80 enrolled

Overview

A Single-Center, Prospective Observational Cohort Study Comparing Perioperative Electroencephalographic Anesthesia Depth Parameters (Electroencephalographic Index, SE/RE Entropy, Burst Suppression Ratio) Between Patients With Preoperative Sleep Disorders and Those Without; To Identify the Independent Effects of Preoperative Sleep Disorders on the Speed of Electroencephalographic Recovery During Emergence, Electroencephalographic Status at Extubation, Intra-PACU Electroencephalographic Fluctuations, and Quality of Emergence.

Preoperative sleep disorder is a common perioperative comorbidity. It impairs central nervous system stability and anesthetic drug metabolism, delays postoperative recovery, and is strongly associated with delayed emergence from general anesthesia, emergence agitation, and postoperative cognitive decline. Electroencephalographic (EEG) monitoring enables continuous, quantitative assessment of anesthetic depth (including EEG index, entropy, and burst suppression ratio), which can reflect central nervous depression more sensitively than conventional vital sign monitoring. To date, there is a lack of evidence based on complete preoperative-intraoperative-postoperative continuous EEG data to clarify the correlations between sleep disorders, anesthetic depth, and emergence quality. This prospective cohort study will collect full-course EEG parameters throughout the perioperative period to identify the effects of preoperative sleep disorders on the stability of anesthetic depth, EEG recovery during emergence, and adverse emergence events, so as to provide evidence-based references for perioperative cerebral protection and precision anesthetic management. Primary Outcome Measures Preoperative \& Postoperative Polysomnography (PSG) indicators: Sleep Efficiency Index (SEI), Total Sleep Time (TST), Arousal Index (AI), and the proportional percentages of N1, N2, N3 stages within NREM sleep and REM sleep; assessments conducted on the night after surgery, postoperative Day 1 and postoperative Week 1.Intraoperative EEG parameters: mean value of EEG index, minimum EEG index value, cumulative duration when EEG index \< 40, maximum Burst Suppression Ratio (BSR).Emergence-phase EEG indicators: recovery time of EEG index, EEG index at extubation, standard deviation of EEG fluctuation in Post-Anesthesia Care Unit (PACU).Emergence quality indicators: extubation time, PACU length of stay, incidence of emergence agitation. Serum Brain-Derived Neurotrophic Factor (BDNF) levels collected at preoperative, intraoperative and postoperative time points.

Study Type

OBSERVATIONAL

Interventions

Exposed cohort (sleep disorder group)COMBINATION_PRODUCT

All participants receive standardized sevoflurane-based general anesthesia for elective non-cardiac surgery. Continuous perioperative electroencephalographic (EEG) monitoring is performed throughout induction, maintenance and emergence phase. Serial scale assessments including PSQI, PSG, MMSE, NRS and delirium evaluation, as well as serial serum BDNF testing are conducted at designated perioperative time points. This cohort consists of patients with preoperative Pittsburgh Sleep Quality Index (PSQI) score ≥ 7, defined as preoperative sleep disorders.

Control cohort (non-sleep disorder group)COMBINATION_PRODUCT

All participants receive identical standardized sevoflurane-based general anesthesia and continuous full-course EEG monitoring during elective non-cardiac surgery. Uniform perioperative scale assessments (PSQI, PSG, MMSE, NRS, postoperative delirium screening) and serial serum BDNF detection are completed at unified time nodes. This control cohort includes patients with preoperative Pittsburgh Sleep Quality Index (PSQI) score \< 7 without preoperative sleep disturbance.

Eligibility

Sex: ALLMin age: 18 YearsMax age: 65 Years

Medical Language ↔ Plain English

Inclusion Criteria: 1. \- Aged 18 to 65 years, with American Society of Anesthesiologists (ASA) physical status classification Ⅰ-Ⅲ; 2. Elective non-cardiac surgery with an expected operative duration longer than 2 hours; 3. Preoperative Mini-Mental State Examination (MMSE) score ≥ 24; 4. Completion of the Pittsburgh Sleep Quality Index (PSQI) assessment 1 day before surgery; 5. Absence of severe cardiac, hepatic, renal or cerebral diseases, and no history of psychiatric or neurological disorders; 6. Voluntary provision of written informed consent. Exclusion Criteria: 1. Preoperative severe cognitive dysfunction, history of traumatic brain injury or stroke; 2. Long-term regular use of sedative-hypnotics, antidepressants or antipsychotics; 3. Intraoperative massive hemorrhage, cardiac arrest, or severe hypoxemia (SpO₂ \< 90% lasting for more than 5 minutes); 4. Inability to cooperate with EEG monitoring or scale evaluation; 5. Pregnancy or breastfeeding status. Drop-out Criteria : 1. Cancellation of scheduled surgery/anesthesia or postoperative admission to the intensive care unit (ICU); 2. Patient withdrawal of study participation; 3. Intraoperative massive hemorrhage, cardiac arrest, or severe hypoxemia (SpO₂ \< 90% lasting for more than 5 minutes); 4. Development of severe postoperative complications; 5. Incomplete data collection or voluntary trial withdrawal.

Outcomes

Primary Outcomes

Emergence Time

Time to emergence from anesthesia:the time interval from discontinuation of anesthetics to patient awakening

Time frame: "perioperative"

Time for recovery of EEG index

The EEG index recovery time during emergence was monitored using the Misamo depth-of-anesthesia monitor. The awake judgment thresholds were set as SE ≥ 85 and RE ≥ 90. Shorter recovery time indicates rapid elimination of anesthetic suppression in the cerebral cortex and smoother emergence; significantly prolonged recovery time suggests accumulation of anesthetics and excessive cerebral cortical suppression. Start point: Discontinuation of maintenance doses of propofol, sevoflurane and remifentanil (rescue analgesics alone are not counted as the drug withdrawal start time). End point: The EEG index steadily reaches the awake threshold without decline for 10p

Time frame: Perioperative

Secondary Outcomes

Dosage of anesthetics:

Dosage of anesthetics: total consumption of propofol, remifentanil and sevoflurane administered from anesthesia induction to emergence.

Time frame: Perioperative

incidence of postoperative delirium

Postoperative delirium was assessed using the Confusion Assessment Method (CAM), which evaluates four dimensions: 1. acute fluctuating course; 2. inattention; 3. disorganized thinking; 4. altered level of consciousness. Higher CAM scores indicate more severe delirium. Score 0: No delirium Score 1-2: Subsyndromal delirium (mild early stage) Score ≥3: Confirmed delirium Score 5-7: Severe delirium

Time frame: CAM assessments were performed and recorded on postoperative Day 1, Day 3 and Day 7.

Numerical Rating Scale (NRS) pain score

The Numerical Rating Scale (NRS) was adopted to evaluate the postoperative pain trend from postoperative Day 1 to Day 7. Higher NRS scores indicate more severe pain.Scores of 1-3 indicate mild pain, 4-7 moderate pain, and 8-10 severe pain.

Time frame: Pain scores were recorded immediately after surgery and daily from postoperative Day 1 to Day 7.

Incidence of postoperative nausea and vomiting (PONV)

Grade 0 No nausea or vomiting Normal Grade 1 Nausea only, no vomiting or retching Mild PONV Grade 2 Retching or intermittent vomiting, less than 2 episodes Moderate PONV Grade 3 Frequent vomiting (≥2 episodes) with gastric contents ejection Severe PONV requiring pharmacological intervention For patients with Grade 2 or above PONV, the event shall be recorded in the Adverse Event section of the CRF, with a notation on whether antiemetics are administered.

Time frame: PONV assessments were conducted upon emergence from anesthesia after surgery, and on postoperative Day 1, Day 2 and Day 3.