O3313: Consequences of Intraoperative Opioid Underdosing: How Regional Nerve Blocks and Disease Complexity Shape Postoperative Pain and Opioid Requirements

Background: Effective postoperative pain management is crucial for improving patient outcomes and minimizing opioid use. Regional nerve blocks, such as Transversus Abdominis Plane (TAP) blocks, are commonly used as part of multimodal analgesia and have shown promise in reducing opioid consumption while providing effective pain relief. This study evaluates the effect of TAP blocks on opioid use, pain control, and recovery outcomes in pediatric laparoscopic appendectomy.

Methods: A retrospective cohort study was conducted on pediatric patients who underwent laparoscopic appendectomy at Nemours Children’s Health from January 1, 2018, to December 31, 2023. Patients were stratified based on appendicitis type (complicated vs. uncomplicated) and whether they received a TAP block. Primary outcomes included intraoperative opioid administration, PACU pain scores, rescue opioid use, length of hospital stay, and discharge opioid prescriptions. Statistical analyses utilized t-tests and chi-square tests.

Results: Patients with uncomplicated appendicitis who received TAP blocks experienced higher postoperative pain scores (6.94 + 2.54 vs 2.99 + 2.33, P < 0.0001) and required more rescue opioids in the PACU (88.5% vs 60.7%, p< 0.0001). In contrast, patients with complicated appendicitis received higher intraoperative opioid doses regardless of TAP block status (0.59 + 0.25 vs 0.51 + 0.19, p< 0.0001) and reported lower postoperative pain scores (0.24 + 0.1 vs 4.02 + 2.95, p< 0.0001). Patients with uncomplicated appendicitis received more opioids overall, intraoperatively and in PACU compared to patients with complicated appendicitis (0.69 + 0.31 vs 0.59 + 0.23, p< 0.0001). Patients who received TAP blocks in both complicated and uncomplicated appendicitis groups were prescribed fewer opioids at discharge (21.6% vs 55.2%, p< 0.0001).

Conclusion: Patients receiving TAP blocks were systematically given lower intraoperative opioid doses, likely due to the assumption that the block alone would provide adequate analgesia. This underdosing resulted in higher postoperative pain scores and increased PACU opioid requirements, making it difficult to assess the TAP block’s true effectiveness. Interestingly, patients with complicated appendicitis reported lower postoperative pain compared to those with uncomplicated appendicitis, a paradox explained by their higher intraoperative opioid dosing. Although the patients with complicated appendicitis received more opioids intraoperatively, the patients with uncomplicated appendicitis received more total opioids when combining both intraoperatively and PACU. Patients who received TAP blocks were less likely to be prescribed opioids at discharge; however, this trend may be driven by clinician prescribing habits than the actual efficacy of the block. These results underscore the importance of appropriate intraoperative analgesic management in postoperative pain outcomes.