Opioid-free anesthesia for breast cancer surgery: A comparison of ultrasound guided paravertebral and pectoral nerve blocks. A randomized controlled trial

Background and Aims: Pectoral block (PECS)-based anesthesia without opioids decreases analgesic requirement, pain scores and post-operative nausea vomiting (PONV) compared to conventional opioid-based general anesthesia in patients undergoing modified radical mastectomy and axillary dissection (MRM-AD). We compared PECS versus Paravertebral Block (PVB) in providing an opioid free, nerve block-based regimen. Outcomes of interest were post-operative analgesic requirement, duration of analgesia, PONV and patient and surgeon satisfaction. Material and Methods: This randomised controlled study involved 58 adult ASA I-III patients posted for MRM-AD. After randomization patients were induced with propofol and maintained on spontaneous ventilation with isoflurane (0.8-1.0 MAC) through i-gel. Ultrasound-guided PECS or PV blocks (30 ml of 0.1% lignocaine + 0.25% bupivacaine + 1 μg/kg dexmedetomidine) were administered. Post-operative pain scores, non-opioid analgesic requirement over 24 hours, PONV, satisfaction of surgeon and patient were measured. Results: Between the two groups, there was no difference in demographics, ASA status, location and volume of breast tumour excised or the duration of surgery. The time from block to incision was significantly longer in the PV group (P = 0.01). There was no difference between the two groups in terms of intra and post-operative parameters, and the median VAS scores for pain at rest or during shoulder abduction were similarly low in both the groups. Conclusion: Both blocks result in equally prolonged analgesia and preclude requirement of opioid analgesics intra and post-operatively. PECS block is associated with lesser time to allow incision. Complications are low in both the groups. Routine use of these blocks to avoid opioids may be studied further. Clinical trial number – Registered in Clinical Trials Registry of India (CTRI/2017/02/007897). http://ctri.nic.in .