This randomized controlled trial aims to compare the incidence of hemidiaphragmatic paralysis (HDP) following ultrasound-guided interscalene block (ISB) versus shoulder pericapsular nerve group (PENG) block in patients undergoing elective shoulder surgery under general anesthesia.
The primary objective is to determine whether the shoulder PENG block reduces the incidence of HDP compared with conventional intrafascial ISB. HDP will be assessed using ultrasound measurement of diaphragmatic excursion 30 minutes after block performance
ASA physical status I-III
Scheduled for elective shoulder surgery under general anesthesia
Able to provide informed consent
Pre-existing diaphragmatic dysfunction
Severe COPD or restrictive pulmonary disease
Neuromuscular disorders
BMI > 40 kg/m²