Efficacy of type-I and type-II pectoral nerve blocks (PECS I and II) in patients undergoing mastectomy: a prospective randomised clinical trial

Introduction
The benefits of type I/II pectoral nerve blocks (PECS I/II), which can be dose dependent, have been examined in different studies. Nonetheless, few randomised trials have been performed in South America. The present randomised trial examined the efficacy of PECS I/II with a higher dose of the local anaesthetic to manage perioperative pain after mastectomy in Brazil.

Material and methods
This was a randomised, parallel, single-centre, and single-blind trial. Eighty participants undergoing elective mastectomy were randomised (1 : 1) to receive PECS I/II plus ultrasound-guided ropivacaine (0.5%) or standard general anaesthesia. The primary outcome was pain intensity at rest 24 hours after surgery, assessed with a numerical rating scale. Haemodynamic outcomes, consumption of opioids, anaesthe­tics and antiemetics, and post-anaesthetic recovery times were also recorded.

Results
Sixty participants (75%) completed the study. The mean age was 54 years, with 57% of participants undergoing mastectomy and 43% undergoing quadrantectomy. Median pain intensity (interquartile range) at rest (24 h postoperatively) was lower in the PECS I/II group compared to the control group: 0 (0–1.75) vs. 1 (1–2), P = 0.021. A smaller number of patients in the PECS I/II group required intraoperative fentanyl (23.3% vs. 83.3%; P < 0.001) and postoperative tramadol (20.0 vs. 76.7%; P < 0.001). Mean doses of fentanyl and tramadol were about 4-5 times lower in the PECS I/II group (P < 0.001). PECS I/II significantly reduced sevoflurane consumption during surgery (P = 0.01). No difference was observed regarding adverse effects.

Conclusions
PECS I/II blockade with high-dose local anaesthetic is efficacious and safe, resulting in lower levels of perioperative pain after mastectomy compared to standard general anaesthesia.