Objective: We aim to determine the optimal timing and approaches for the first tangential excision (TE) of severely burned patients with ≥70% total body surface area (TBSA). Background: Early TE is the gold-standard surgical therapy for full-thickness burns. However, there are debates about its optimal timing and approaches for severely burned patients with ≥70% TBSA. Methods: This study included 185 patients in the Kunshan factory explosion. We focused on surgical timing, surgical area, and main wound covering method for the first TE. We determined the optimal cutoff 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 (OS). Then, we utilized multivariate 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 TE in >3 days (hazard ratio = 2.37, 95% CI = 1.05–5.40, P = 0.039) and surgical area >48% TBSA (hazard ratio = 2.41, 95% CI = 1.46–4.00, P < 0.001) were independent risk factors in the Kunshan cohort for OS of patients with ≥70% TBSA, and were associated with a higher rate of complications. Subgroup analysis revealed that the timing and TBSA of the first TE were influenced by several treatment and complication factors (hemodynamic status and types of hospitals). Main wound-covering methods were a significant confounding factor. Patients with more autograft showed better OS than those with more extensive use of temporary skin substitutes in the Kaplan-Meier survival analysis ( P < 0.001). However, main wound-covering methods are influenced by the severity of injury, availability of autologous skin source, as well as medical resources. In addition, external validation demonstrated consistent results and acceptable calibration. Conclusions: This study identified the optimal timing and approaches for first TE, validating them as independent prognostic factors for patients with ≥70% TBSA. However, considering the various confounding factors, treatment for each patient should be tailored.

Background: Burn injuries with ≥70% total body surface area (TBSA) are especially acute and life-threatening, leading to severe complications and terrible prognosis, while a powerful model for the prediction of overall survival (OS) is lacking. The objective of this study is to identify prognostic factors for the OS of patients with burn injury ≥70% TBSA and construct and validate a feasible predictive model. Materials and methods: Patients diagnosed with burns ≥70% TBSA admitted and treated between 2010 and 2020 in our hospital were included. A cohort of the patients from the Kunshan explosion were assigned as the validation set. The χ ² test and K-M survival analysis were conducted to identify potential predictors for OS. Then, multivariate Cox regression analysis was performed to identify the independent factors. Afterward, we constructed a nomogram to predict OS probability. Finally, the Kunshan cohort was applied as an external validation set. Results: Sex, the percentage of third-degree and fourth-degree burns as well as organ dysfunction were identified as significant independent factors. A nomogram only based on the factors of the individuals was built and evidenced to have promising predictive accuracy, accordance, and discrimination by both internal and external validation. Conclusions: This study recognized significant influencing factors for the OS of patients with burns ≥70% TBSA. Furthermore, our nomogram proved to be an effective tool for doctors to quickly evaluate patients’ outcomes and make appropriate clinical decisions at an early stage of treatment.