Optimal Timing and Approaches for First Tangential Excision in Patients with ≥70% TBSA Burns: Insights from a Retrospective Cohort of a Mass Casualty Incident.

Objective: We aim to determine the optimal timing and approaches for first tangential excision of severely burned patients ≥70% total body surface area (TBSA).

Background: Early tangential excision is the gold-standard surgical therapy for full-thickness burns. However, there are debates about its optimal timing and approaches for severely burned patients ≥70%TBSA.

Materials and methods: This study included 185 patients in the Kunshan factory explosion. We focused on surgical timing, surgical area, and main wound covering method for first tangential excision. We determined the optimal cut-off values for surgical timing and area using R language "surv_cutpoint" and "surv_categorize" functions, and utilized the Kaplan-Meier survival analysis to investigate their influences on patients' overall survival. Then, we utilized multi-variate Cox regression analysis to identify independent factors, and performed subgroup analyses to find confounding factors. Finally, we employed a 10-year single-center cohort of 144 patients with burn injury ≥70% TBSA for external validation.

Results: Performing first tangential excision in >3 days (hazard ratio=2.37, 95% confidence interval=1.05-5.40, P =0.039) and surgical area > 48% TBSA (hazard ratio=2.41, 95% confidence interval=1.46-4.00, P <0.001) were independent risk factors in the Kunshan cohort for overall survival of patients ≥70% TBSA, and were associated with higher rate of complications. Subgroup analysis revealed that the timing and TBSA of first tangential excision were influenced by several treatment and complications factors (hemodynamic status and types of hospitals). Main wound covering methods was a significant confounding factor. Patients with more autograft showed better overall survival than those with more extensive use of temporary skin substitutes in the Kaplan-Meier survival analysis ( P <0.001). However, main wound covering methods influenced by the severity of injury, availability of autologous skin source, as well as the medical resources. Additionally, external validation demonstrated consistent results and acceptable calibration.

Conclusion: This study identified the optimal timing and approaches for first tangential excision, validating them as independent prognostic factors for patients with ≥70% TBSA. However, considering the various confounding factors, treatment for each patient should be tailored.