Efficacy and complications of analgesic techniques for the treatment of moderate to severe postoperative acute pain

Abstract

Introduction: Despite the efforts and the available evidence, moderate to severe acute postoperative pain (APP) continues to have a high prevalence in our setting. As part of a balanced or multimodal analgesia strategy, regional analgesia techniques offer adequate analgesic control with fewer undesirable effects (that the exclusive use of opioids), although they are not free of complications and do not apply to all surgeries. This study aimed to assess the efficacy of analgesic techniques for the treatment of moderate to intense APP, the incidence of complications associated with these techniques, and the relationship between APP and the presence of chronic pain. Patients and methods: This retrospective study included 728 patients in which analgesic techniques such as epidural analgesia, continuous perineural analgesia, and morphine Patient Controlled Analgesia (PCA) were indicated to treat moderate to severe APP between October 2018 and October 2020. The patients were evaluated by the APP service at 24 and 48 hours, the pain was recorded with the NRS (Numerical Rating Scale), and the study also registered the presence of adverse reactions and/or complications, the use of multimodal analgesia, and the consumption of morphine in equivalent intravenous doses. Pain levels were classified as mild (NRS: 0-3), moderate (NRS: 4-6) and intense (NRS greater than or equal to 7). Results: Approximately 60 % of all patients presented mild pain at 24 hours and 70 % at 48. Epidural opioianalgesia in abdominal surgery presented 71.8 % mild pain on the first day and 83 % on the second. The surgeries with the highest levels of moderate and severe pain were spinal surgery using morphine PCA and knee replacement with continuous femoral nerve block. The morphine consumption recorded in the PCA was 25.8 mg (SD 18.4) at 24 hours and 18.6 mg (SD: 14.6) at 48 hours. There were no serious complications associated with any of the techniques, except for accidental removal of epidural catheters (3.6 %). In continuous peripheral nerve blocks, accidental withdrawals (13 %), and leakage from the catheter insertion site (6.4 %) were the most frequent complications. There was a significant relationship between chronic pain and pain intensity (p = 0.000). Conclusions: Analgesic techniques for the management of APP, achieve better analgesic levels with few complications. The role of effective and safe thoracic epidural analgesia in open abdominal surgery stands out. Patients with a history of chronic pain had higher percentages of moderate and severe pain at 24 and 48 hours.