This prospective observational study aims to evaluate whether the use of ultrasound-guided fascial plane blocks is associated with a lower incidence of postoperative pulmonary complications in adult patients undergoing elective major abdominal surgery under general anesthesia.

Patients will be observed in two groups based on routine clinical practice: those who receive an ultrasound-guided fascial plane block for postoperative analgesia and those managed with other standard analgesic methods. The choice of analgesic technique will be determined by the responsible anesthesia team and not influenced by the study.

Postoperative pulmonary complications occurring within the first 7 days after surgery will be recorded using reopening the European Perioperative Clinical Outcome (EPCO) criteria. Secondary outcomes will include unplanned intensive care unit admission, length of hospital stay, and 30-day mortality. No additional procedures or interventions will be performed for research purposes.

Inclusion Criteria:

• Age 65 years or older
• Scheduled for elective major abdominal surgery (e.g., colorectal, hepatobiliary, pancreatic, or gastric surgery)
• ASA physical status II-III
• Ability to provide written informed consent
• Planned use of general anesthesia with or without adjunct regional techniques

Exclusion Criteria:

• Refusal or inability to provide informed consent
• Known allergy or contraindication to local anesthetics
• Coagulopathy or ongoing anticoagulant therapy contraindicating regional anesthesia
• Infection at the site of planned block
• Pre-existing chronic opioid use or chronic pain syndrome
• Severe hepatic, renal, or cardiac failure (e.g., Child-Pugh C, end-stage renal disease, EF <30%)
• Cognitive impairment or severe dementia preventing adequate pain assessment
• Emergency surgery
• Body mass index (BMI > 40 kg/m²)

The study population consists of patients aged 65 years and older who are scheduled to undergo elective major abdominal surgery under general anesthesia. Eligible participants will be managed in a tertiary care hospital and will be allocated to either a fascial plane block group or a control group receiving standard perioperative analgesia. The study aims to evaluate postoperative outcomes in an elderly surgical population with comparable baseline characteristics.

Individual participant data will not be shared due to institutional policies and concerns regarding patient confidentiality and data protection.