Minimization of intra-operative opioid use is an area of ongoing research interest with several potential benefits to the patient. Pre-emptive analgesia, defined as the administration of an analgesic before surgery to prevent establishment of central sensitization of pain, is one avenue that has been explored to achieve this. A retrospective observational study was undertaken to examine the effect of pre-emptive paracetamol on intra-operative opioid requirements. The medical and operative data of 156 patients who underwent day-case wide local excision and sentinel lymph node biopsy with and without regional block surgery at our center between October 2019 and May 2022 was carried out. Data were collected on demographics, total intra-operative and immediate post-operative opioid consumption. 57 patients did not receive pre-emptive paracetamol while 90 did. Baseline characteristics were similar. Our results showed a statistically significant reduction in morphine (p <0.029) and remifentanil (p <0.007) consumption in patients who received a regional block and pre-emptive paracetamol. Those who did not receive a regional block and were given pre-emptive paracetamol had a decrease in OxyNorm (p <0.022) requirements. A combination of general anesthesia (GA), regional block and pre-emptive paracetamol reduced intra-operative consumption of Fentanyl, OxyNorm, diclofenac, dexketoprofen, and clonidine (P <0.001) when compared to just GA alone. Use of pre-emptive paracetamol in reduction of intra-operative opioid requirements showed promising results but larger studies may strengthen the evidence for this association. A multimodal analgesic approach that utilizes pre-emptive paracetamol can be a viable method to decrease intra-operative of analgesic requirements.

Introduction The open prosthetic repair of inguinal hernias under local anaesthesia (LA) is well established, with the concept of intraoperative \'pre-emptive analgesia\' evolving so that patients are as comfortable as possible. We used a peri-incisional LA solution in patients undergoing day-case inguinal hernioplasty under general anaesthesia (GA) and recorded use of analgesia in the immediate postoperative period. Methods In this observational cohort study, 100 consecutive unselected men underwent open inguinal hernia repair as a day case. Of these, 75 underwent repair under GA and 25 with peri-incisional LA solution (equal mixture of 0.5% bupivacaine and 1% lignocaine with 1:200,000 adrenaline). Analgesia prescribed at induction, for maintenance and after cessation of anaesthesia was scored in accordance with the World Health Organization (WHO) analgesic ladder. Results The median age in the GA group was 59 years (range: 25-89 years) and in the GA+LA group, it was 62 years (range: 27-88 years). Of the 100 patients, 82 underwent a mesh plug repair by seven surgeons whereas 18 underwent a flat (Lichtenstein) mesh repair by two surgeons. WHO analgesic induction and postoperative scores were significantly lower in the GA+LA group (p=0.034 and p<0.001 respectively). There was also a significant difference in use of postoperative antiemetics (23% vs 0% in the GA only and GA+LA cohorts respectively, p=0.020). Six patients (8%) in the GA group failed day-case discharge criteria. Conclusions Patients undergoing contemporary day-case GA inguinal hernioplasty with pre-emptive LA solution infiltration require lower levels of postoperative opioid analgesia and antiemetics. These cases are less likely to fail discharge criteria for planned day surgery.