Predictive value of perioperative peripheral blood cells counts for bacteremia and 90-day mortality in severe burn patients.

Objective: Burn bacteremia is related to immune barrier damage, but whether the level of circulating immune cells predicts outcomes in severe burns is still not clear. This study aimed to explore the predictive value of perioperative blood cells of the first surgery after burn for bacteremia and 90-day death.

Methods: Data from severe burn patients treated at the First Affiliated Hospital of Sun Yat-sen University from 2011 to 2020 were retrospectively analyzed. Data on monocytes (M), lymphocytes (L), white blood cell-to-platelet ratio (WPR), neutrophil-to-lymphocyte ratio (NLR) in peripheral blood and changes in temperature (T-37) were collected at one day before(X0), the first day after (X1) and the third day after (X3) the primary surgery.Univariate and multivariate logistic regression were used to identify the independent risk factors of bacteremia and death within 90 days, which were used to establish the risk prediction models (xbac and x90d-m) in severely burned patients. Severe burn cases from two other burn centers were selected to verify the prediction models.

Results: We analyzed 169 severe burn cases in the training dataset, with a 90-day mortality of 21.3% (36/169); 56 (33.1%) patients experienced burn bacteremia. Higher M0, WPR0, NLR0, NLR3, T3-37, ∆M (M0-M3) and lower M3, L3 were associated with higher risk of bacteremia (P < 0.05). Multivariate regression analysis showed that SOFA0, WPR0, M3, and T3-37 were independently associated with bacteremia. The prediction model for bacteremia Xbac = 0.1809 × SOFA0 + 6.532 × WPR0-1.171 × M3 + 0.6987 × T3-37- 2.297. TBSAB, SOFA0, and ∆M (M0-M3) were independently correlated with 90-day mortality. The risk prediction model X90d-m= 0.055 × TBSAB + 0.301 ×SOFA0 + 1.508 × ∆M - 7.196. External validation suggested that the specificity, sensitivity and AUC of the prediction model Xbac was 90.7%, 62.5% and 0.797, respectively; of the prediction model X90d-m was 69.2%, 90.0% and 0.873, respectively.

Conclusion: Peripheral M3, WPR0 and ∆M (M0-M3) during the primary surgery has reasonable predictive ability for bacteremia and 90-day mortality in severe burn patients, which could inform clinical antimicrobial judgment and prognostication.