The goal of this randomized, double-blind, placebo-controlled, 2×2 factorial trial is to evaluate the effect of intraoperative dexmedetomidine combined with either femoral nerve block (FNB) or adductor canal block (ACB) on postoperative sleep quality in patients aged 18-85 years with ASA I-III undergoing elective knee arthroscopy under general anesthesia.
The main questions it aims to answer are:
1. Does intraoperative dexmedetomidine infusion (0.5 μg/kg/h) improve postoperative sleep quality as measured by the Pittsburgh Sleep Quality Index (PSQI) at 24 h and 48 h after surgery? 2. Is there an interaction between the type of nerve block (FNB vs. ACB) and the use of dexmedetomidine on postoperative sleep quality?
Age 18 to 85 years.
American Society of Anesthesiologists (ASA) physical status I to III.
Body Mass Index (BMI) between 18 and 30 kg/m² and body weight > 50 kg.
Scheduled for elective knee arthroscopy under general anesthesia.
Refusal to participate in the study.
Inability to communicate effectively.
Known allergy or contraindication to any study drug (ropivacaine, dexmedetomidine, propofol, sufentanil, remifentanil, vecuronium, or sevoflurane).
History of knee trauma or knee surgery; diagnosed with immune system disorders (e.g., rheumatoid arthritis, systemic lupus erythematosus); neuromuscular diseases or psychiatric disorders; restless legs syndrome (RLS); periodic limb movement disorder (PLMD).