Comparison of Paravertebral Versus Epidural Block for Post-thoracotomy Pain Control

This is a randomized, assessor‐blinded, non‐inferiority clinical trial conducted atHospital de Clínicas de Porto Alegre, Brazil, in adult patients undergoing elective openthoracotomy with one‐lung ventilation. The objective is to compare the analgesic efficacyof continuous thoracic paravertebral block (BPV) versus continuous thoracic epiduralblock (BPD) for postoperative pain control during the first 48 hours after surgery.Patients will be randomly allocated to two groups (40 per group). In the BPV group, theparavertebral catheter is inserted at the end of surgery under direct thoracoscopicvision (without ultrasound), using a bolus of ropivacaine 0.375% (15 mL fractionated)followed by continuous infusion of bupivacaine 0.125% at 0.10 mL/kg/h. In the BPD group,the epidural catheter is inserted at the beginning of surgery using theloss‐of‐resistance technique with the same bolus and infusion regimen. The targetdermatomal level is T5‐T7 (or T5‐T9).The primary outcome is the mean pain score at rest measured by the Numeric Verbal Scale(NVS 0‐10) at 6, 12, 24, and 48 hours postoperatively. Secondary outcomes include pain onmovement, total opioid consumption (converted to morphine equivalents), block‐relatedcomplications (hypotension, urinary retention, technical failure, motor block),clinically significant pulmonary and cardiovascular complications, length of hospitalstay, and patient satisfaction with analgesia.Randomization is centralized using variable block sizes and sealed numbered envelopes.Outcome assessors are blinded to allocation. Both groups receive identical multimodalanalgesia and a standardized rescue protocol. The sample size of 80 participants wascalculated to demonstrate non‐inferiority with a margin of 1 point on the NVS (expectedSD = 1.5; 80% power; one‐sided α = 0.025).The study was approved by the Research Ethics Committee of HCPA (Opinion No. 8.544.882;CAAE 98467026.8.0000.5327) and will be conducted in accordance with the Declaration ofHelsinki and current Brazilian regulations.