Comparison of 0.25% and 0.125% bupivacaine in hyperthermic intraperitoneal chemotherapy (HIPEC): a single-center experience

<p><strong>Background:</strong> Cytoreductive surgery (CRS) with hyperthermic intraperitoneal chemotherapy (HIPEC) causes severe postoperative pain; thoracic epidural analgesia is recommended, but the optimal epidural bupivacaine concentration has not been studied in this setting. We compared 0.25% and 0.125% epidural bupivacaine after CRS + HIPEC.</p> <p><strong>Methodology:</strong> This retrospective cohort study included 77 adults who underwent CRS + HIPEC at a tertiary care center between January 2017 and December 2021. All received epidural fentanyl 2 mcg/ml with 0.125% (n = 59) or 0.25% (n = 18) bupivacaine (non-randomized). Pain severity was categorized from visual analog scale assessments. Secondary outcomes were sensory block level, supplementary intravenous (IV) analgesia, patient-controlled analgesia (PCA), and adverse effects. Groups were compared using Fisher&rsquo;s exact or Fisher&ndash;Freeman&ndash;Halton exact tests.</p> <p><strong>Results: </strong>Mild pain occurred in 11/18 patients (61.1%) receiving 0.25% and 19/59 (32.2%) receiving 0.125% bupivacaine (exploratory risk difference 28.9 percentage points; 95% confidence interval 3.1&ndash;50.3), moderate pain in 7 (38.9%) and 38 (64.4%), and severe pain in 0 and 2 (3.4%), respectively. The overall pain-severity distribution did not differ significantly (p = 0.101), nor did sensory block level (p = 0.284), supplementary IV analgesia (p = 0.272), PCA use (p = 1.000), or nausea and vomiting (p = 0.556). No patient had pruritus or<br />motor complications.</p> <p><strong>Conclusion:</strong> No statistically significant differences in pain outcomes or adverse effects were detected between the two concentrations. The small, unequal, and non-randomized groups preclude conclusions about equivalence or superiority; adequately powered prospective studies are needed.</p>