Impact of Thoracic Irrigation on Empyema Patterns in Trauma Patients

Authors:
Katherine Russo, Joshua Preston, Wen Yang, Randi Smith, Jonathan Nguyen, Jason Sciarretta

Body of Abstract:
Background:

Empyema is a significant complication following traumatic hemothorax, contributing to prolonged hospitalization, increased morbidity, and the need for invasive interventions. Thoracic irrigation (TI) has emerged as a minimally invasive strategy for managing retained hemothorax, yet its influence on the development and microbiologic profile of subsequent empyema remains unclear.

Methods:

A retrospective review was performed of trauma patients who underwent TI for retained hemothorax at an urban Level I trauma center between 8/2023 and 8/2025, identifying those who subsequently developed empyema. A historical comparison cohort included all traumatic empyema cases over a four-year period (1/2019 – 7/2023) preceding TI protocol implementation. Empyema was defined by the presence of positive pleural cultures. Data collected included demographics, injury patterns, pleural microbiology, ICU length of stay (LOS), and mortality. Continuous and ordinal variables were summarized as median [IQR] and compared using the Wilcoxon rank-sum test. Categorical variables were summarized as n (%) and compared using Fisher’s exact test.

Results:

Among 124 patients who underwent TI during the study period, the overall empyema rate was 2.4%. A total of 35 culture-proven empyemas were identified: 3 post-TI patients and 32 historical controls without TI. Patients who developed empyema after TI had a significantly longer time to diagnosis compared with those without TI (30 days [29.5-33] vs. 13 days [9.8-19.5], p=0.031). Polymicrobial empyema occurred less frequently in the TI group (33% vs. 72%), though this difference did not reach statistical significance. Rates of anaerobic infection were similar between cohorts (33% vs. 41%). No significant differences were observed in demographics, injury mechanism, ISS, thoracic AIS, ICU LOS, or mortality between groups (Table 1).

Conclusion:

In trauma patients who developed empyema, those who underwent prior thoracic irrigation demonstrated delayed onset of empyema and a lower observed rate of polymicrobial infection compared with patients who did not undergo TI. Although limited by the small number of post-TI empyemas, these findings suggest that TI may influence the microbiologic profile or temporal development of pleural space infection. Larger studies are needed to clarify the impact of TI on empyema pathophysiology and clinical outcomes following traumatic hemothorax.