Association of delayed enteral nutrition with hospital-acquired pneumonia and 30-day mortality following craniotomy for severe traumatic brain injury: a retrospective cohort study.

Background: Hospital-acquired pneumonia (HAP) is a serious complication after craniotomy for severe traumatic brain injury (TBI), but evidence on modifiable factors, especially delayed enteral nutrition, remains limited. Objective: To evaluate factors associated with HAP after severe TBI surgery, focusing on enteral nutrition timing and the association between HAP and 30-day mortality. Methods: This retrospective cohort study included 600 adult patients undergoing craniotomy for severe TBI who survived >48 h. HAP was diagnosed according to CDC/NHSN criteria. Multivariable logistic regression identified factors associated with HAP, and a fully adjusted model assessed the HAP-mortality association. Model performance was assessed by the AUC and Hosmer-Lemeshow test. Sensitivity analyses included forced inclusion of tracheostomy and comparison of the primary model (pre-HAP ventilation duration) with the total ventilation model. A 48-h landmark analysis was also performed. The primary outcome was postoperative HAP; secondary outcomes were ICU stay and 30-day mortality. Results: Postoperative HAP incidence was 11.5%. After adjustment, delayed enteral nutrition (≥48 h) was independently associated with HAP (OR = 4.46, 95% CI: 2.52-8.19, Conclusion: In severe TBI patients undergoing craniotomy, delayed enteral nutrition was independently associated with increased HAP risk, and HAP was associated with higher 30-day mortality. These findings highlight the potential importance of early enteral nutrition, but causal inference is limited by the observational design; prospective studies are needed.