Effects of Combined Pericapsular Nerve Group (PENG) and Lateral Femoral Cutaneous Nerve (LFCN) Blocks on Anaesthetic Requirements and Electroencephalographic Depth of Anaesthesia During Total Hip Arthroplasty: A Randomized Controlled Trial

This prospective, randomized controlled trial aims to evaluate the effects of combined pericapsular nerve group (PENG) and lateral femoral cutaneous nerve (LFCN) blocks on intraoperative anaesthetic consumption and electroencephalographic (EEG)-derived anaesthetic depth in patients undergoing elective total hip arthroplasty. A total of 50 adult patients will be randomly allocated to two groups: combined PENG and LFCN blocks followed by general anaesthesia, or general anaesthesia alone. Anaesthetic depth will be monitored using the SedLine EEG monitoring system. The primary outcome will be intraoperative sevoflurane consumption. Secondary outcomes will include remifentanil consumption, EEG-derived parameters including Patient State Index (PSI) and suppression ratio, haemodynamic variables, and recovery characteristics. The study aims to determine whether combined regional blocks reduce anaesthetic requirements while maintaining adequate EEG-guided anaesthetic depth.

Inclusion Criteria: * Patients aged 18-65 years * American Society of Anesthesiologists (ASA) physical status I-III * Scheduled for elective primary total hip arthroplasty * Undergoing general anaesthesia * Provision of written informed consent to participate in the study Exclusion Criteria: * Known allergy to local anaesthetics * Contraindications to PENG or LFCN block * Infection at the planned block injection site * Coagulopathy or anticoagulant therapy considered unsuitable for regional anaesthesia * Chronic opioid use * Significant neurological disorders that may interfere with EEG assessment * Cognitive impairment preventing comprehension of the study protocol or provision of informed consent * Inability to perform SedLine monitoring * Inability to obtain written informed consent