Influence of Nociception Level Monitor (NOL)-Guided Analgesic Delivery on Perioperative Course in Breast Surgeries: A...

Background and Objectives: Breast cancer surgeries offer challenges in perioperative pain management, especially in the presence of inherent risk of postoperative nausea and vomiting (PONV) and postmastectomy pain syndrome (PMPS). Inappropriate opioid consumption was speculated as one of the reasons. Through this study, the influence of objective pain monitoring through a nociception level monitor (NOL) on perioperative course in breast surgeries was investigated. Materials and Methods: This was a prospective randomized study conducted at a regional hospital. Sixty female patients posted for breast cancer surgery were randomized equally into study and control groups. Both groups were monitored using BIS and NOL, but in the control group, the NOL monitor was blinded by a cover. Both groups received propofol and remifentanil through target-controlled infusions (TCIs) along with interpectoral, pectoserratus (PECS II), and superficial pectointercostal block. The primary outcome was intraoperative opioid consumption. Secondary outcomes were PONV, eligibility for discharge from the recovery room, and symptoms of PMPS after three months. Results: Two patients were excluded. The study group received significantly less remifentanil (0.9 mg in the study group vs. 1.35 mg in the control group, p = 0.033) and morphine (2.5 mg in study group vs. 5 mg in control group, p = 0.013). There was no difference in PMPS symptoms between the groups. The study group showed longer duration of inadequate analgesia (i.e., 7% vs. 10% of the total intraoperative period in control and study group, respectively, p = 0.008). There was no difference in time to eligibility for discharge from the recovery room between the groups. Conclusions: NOL monitor-guided analgesic delivery reduces intraoperative opioid consumption. No difference was demonstrated on PONV, eligibility for discharge from the recovery room, or PMPS symptoms.