AIM Despite a wide variety of models found in literature, choosing the right one can be difficult as many of them are lacking precise methodology. This study aims to analyze and compare original burn models in terms of burn device and technique, parameters, and wound depth assessment. METHODS A systematic search was performed according to PRISMA guidelines on studies describing original experimental burn models in rats. The adapted PICO formula and ARRIVE checklist were followed for inclusion and assessment of quality of studies. Characteristics of animals, burn technique, burn parameters and method of histological confirmation of burn depth were recorded. RESULTS Twenty-seven studies were included in the final analysis. Most studies used direct contact with skin for burn infliction (n=20). The rat’s dorsum was the most common site (n=18). Ten studies used manually controlled burn devices, while ten designed automatic burn devices with control over temperature (n=10), exposure time (n=5), and pressure (n=5). Most studies (n=7) used a single biopsy taken from the center of the wound to confirm burn depth immediately after burn infliction. CONCLUSION From the wide variety of burn models in current literature, our study provides an overview of the most relevant experimental burn models in rats aiding researchers to understand what needs to be addressed when designing their burn protocol. Models cannot be compared as burn parameters variate significantly. Assessment of burn depth should be done in a standardized, sequential fashion in future burn studies to increase reproducibility.

BACKGROUND Upper gastrointestinal (GI) bleeding is a life-threatening condition with high mortality rates. AIM To compare the performance of pre-endoscopic risk scores in predicting the following primary outcomes: In-hospital mortality, intervention (endoscopic or surgical) and length of admission (≥ 7 d). METHODS We performed a retrospective analysis of 363 patients presenting with upper GI bleeding from December 2020 to January 2021. We calculated and compared the area under the receiver operating characteristics curves (AUROCs) of Glasgow-Blatchford score (GBS), pre-endoscopic Rockall score (PERS), albumin, international normalized ratio, altered mental status, systolic blood pressure, age older than 65 (AIMS65) and age, blood tests and comorbidities (ABC), including their optimal cut-off in variceal and non-variceal upper GI bleeding cohorts. We subsequently analyzed through a logistic binary regression model, if addition of lactate increased the score performance. RESULTS All scores had discriminative ability in predicting in-hospital mortality irrespective of study group. AIMS65 score had the best performance in the variceal bleeding group (AUROC = 0.772; P < 0.001), and ABC score (AUROC = 0.775; P < 0.001) in the non-variceal bleeding group. However, ABC score, at a cut-off value of 5.5, was the best predictor (AUROC = 0.770, P = 0.001) of in-hospital mortality in both populations. PERS score was a good predictor for endoscopic treatment (AUC = 0.604; P = 0.046) in the variceal population, while GBS score, (AUROC = 0.722; P = 0.024), outperformed the other scores in predicting surgical intervention. Addition of lactate to AIMS65 score, increases by 5-fold the probability of in-hospital mortality ( P < 0.05) and by 12-fold if added to GBS score ( P < 0.003). No score proved to be a good predictor for length of admission. CONCLUSION ABC score is the most accurate in predicting in-hospital mortality in both mixed and non-variceal bleeding population. PERS and GBS should be used to determine need for endoscopic and surgical intervention, respectively. Lactate can be used as an additional tool to risk scores for predicting in-hospital mortality.