Safety and Analgesic Consumption Impact of Continuous Peripheral Regional Analgesia in Earthquake-Related Crush Injury: A Retrospective Cohort Study

Background: The 6 February 2023 Kahramanmaraş earthquake caused an unprecedented burden of crush-related extremity trauma. Continuous peripheral regional analgesia is frequently used in these patients, but its safety regarding renal outcomes and its effect on systemic opioid consumption have not been quantified in comparative cohort data. Methods: We conducted a retrospective, exploratory cohort study of 181 hospitalizations (141 patients) following the earthquake, comparing patients who received a continuous peripheral nerve catheter with those managed without one. No prospective sample-size calculation was performed. The primary outcome was acute kidney injury (AKI), defined per adapted KDIGO criteria; the secondary outcome was systemic opioid exposure, assessed both as opioid-days and, in a dose-based sensitivity analysis, as morphine milligram equivalents (MME). Because patients contributed multiple admissions, regression models used cluster-robust standard errors. A propensity-score-matched sensitivity analysis (age, sex) addressed confounding by indication, and intensive care unit (ICU) days were added as a further covariate in sensitivity models. Results: Catheter and non-catheter groups had similar age (p = 0.369) but differed in length of stay (median 42 vs. 16 days) and surgical procedures (10 vs. 2), reflecting catheter-selection criteria; detailed injury-severity and comorbidity data were not available for either group. Catheter use was not significantly associated with AKI (adjusted OR 0.49, 95% CI 0.16–1.47, p = 0.203) or with systemic opioid-day rate (adjusted RR 1.15, 95% CI 0.88–1.51, p = 0.294). Results were materially unchanged after adding ICU days as a covariate (AKI OR 0.42, p = 0.148, n = 123; opioid-days RR 1.23, p = 0.223, n = 160) and when opioid exposure was expressed as MME per day (adjusted ratio 1.32, 95% CI 0.73–2.38, p = 0.361, n = 165). A propensity-matched analysis (26 pairs) was concordant for all outcomes. Conclusions: In this exploratory, hypothesis-generating cohort, we did not detect a significant association between continuous regional analgesia and either AKI risk or opioid consumption across six complementary analyses. These non-significant findings do not establish equivalence or safety, particularly given wide confidence intervals, a modest number of events, incomplete clinical characterization, and residual confounding that could not be fully resolved with the available data; they should be regarded as hypothesis-generating pending confirmation in better-characterized, adequately powered, multicenter cohorts.