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
Interscalene block is widely used for shoulder surgery but is frequently associated with ipsilateral hemidiaphragmatic paralysis due to phrenic nerve involvement. The shoulder PENG block is a more distal pericapsular technique targeting articular branches and may reduce diaphragmatic impairment. This prospective, parallel-group, randomized controlled trial will enroll 68 adult patients scheduled for elective shoulder surgery. Participants will be randomly assigned (1:1) to receive either ultrasound-guided intrafascial interscalene block or ultrasound-guided shoulder PENG block. Both groups will receive 15 mL of 0.25% bupivacaine (total dose 37.5 mg). Diaphragmatic excursion will be measured at baseline and 30 minutes after block performance using M-mode ultrasonography by a blinded assessor. The primary endpoint is hemidiaphragmatic paralysis defined as ≥25% reduction in diaphragmatic excursion from baseline. Partial and complete paralysis will be analyzed as a composite binary outcome.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
PREVENTION
Masking
DOUBLE
Enrollment
70
Procedure: Ultrasound-guided conventional intrafascial interscalene block at C5-C6 level Drug: 15 mL of 0.25% bupivacaine (37.5 mg)
Procedure: Ultrasound-guided shoulder pericapsular nerve group block Drug: 15 mL of 0.25% bupivacaine (37.5 mg)
Hemidiaphragmatic Paralysis (HDP)
≥25% reduction in diaphragmatic excursion from baseline measured by ultrasound M-mode.
Time frame: 30 minutes after block performance
Complete hemidiaphragmatic paralysis (≥75% reduction or paradoxical motion)
≥75% reduction or paradoxical motion
Time frame: 30 minutes after block performance
Absolute and percentage change in diaphragmatic excursion
change in diaphragmatic excursion
Time frame: 30 minutes after block performance
Total 24-hour tramadol consumption (mg)
Total 24-hour tramadol consumption (mg)
Time frame: postoperative 24 hours
NRS pain scores (from 0 to 10: 0 stands for no pain, 10 stands for severe pain)
Postoperative pain scores
Time frame: postopertaive 2 hours, 6 hours, 12 hours, 24 hours
Rescue morphine consumption (mg)
Rescue morphine consumption (mg)
Time frame: postoperative 24 hours
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