11.12 Non-Alcoholic Fatty Liver Disease (NAFLD) Is Associated With Increased Post-Traumatic Pneumonia

J. A. Bailey1, L. Brown1, A. Y. Parikh2, R. H. Wachsberg1, A. Kunac1, B. Koneru1, D. H. Livingston1  1New Jersey Medical School,Newark, NJ, USA 2Morristown Medical Center,Morristown, NJ, USA

Introduction:  Non-alcoholic fatty liver disease (NAFLD) has become epidemic in the US and has been associated with pulmonary complications following elective surgery and liver transplantation, but has not been considered as a comorbidity after trauma. Abdominal CT scanning can detect moderate-to-severe fatty infiltration of the liver. We hypothesized that trauma patients with pulmonary complications would have an increased incidence of pre-existing NAFLD compared to the trauma population at-large. 

Methods:  Data on adult ICU trauma patients with the diagnosis of ventilator-associated pneumonia (VAP) (N=147) were extracted from a prospective ICU respiratory database. Presence of NAFLD was identified using defined metrics comparing liver-to-spleen density on their admission abdominal CT. Analysis included demographics, ventilator and ICU days, respiratory failure, recurrent pneumonia, bacteriology, and mortality. To determine the baseline prevalence of NAFLD in the trauma population, 130 additional consecutive trauma patients who underwent abdominal CT on admission were analyzed.  

Results: The prevalence of NAFLD in the general trauma population was 27%. In contrast, NAFLD was present in 50% of trauma ICU patients who went on to develop VAP (p=0.001).  Known risk factors for VAP were similar in patients with and without NAFLD:  age (43 vs 49 years), BMI (28 vs 28), emergent intubation (68% vs 65%), TBI with head AIS ≥3 (31% vs 32%), and ISS (30 vs 33).  There were no differences in bacteriology, ventilator days or ICU stay.   

Conclusion: The presence of NAFLD on admission CT was significantly higher in ICU patients with post-traumatic VAP compared to the baseline trauma population. Given other risk factors were equal, we postulate that NAFLD may represent a pre-existing inflammatory focus that may alter the immune response to injury and represent an independent risk factor for post traumatic VAP.  The mechanisms for the increase in VAP remain speculative but this novel observation requires further prospective study, which might provide potential avenues of intervention to decrease the incidence of post-traumatic VAP.