Ventilator-associated pneumonia in severe traumatic brain injury: the clinical significance of admission chest computed tomography findings

Abstract

Background: Ventilator-associated pneumonia (VAP) in severe traumatic brain injury (STBI) is a significant morbidity. Bilateral dependent consolidation (BDC) can be seen on admission chest computed tomography (CCT) in STBI. We hypothesize that this finding may be associated with VAP.

Materials and methods: We retrospectively studied patients who sustained STBI after blunt injury and survived >48 h, who were admitted over a 40-mo period. We defined STBI as an admission Glasgow Coma Scale Score ≤ 8. We identified VAP by an elevated white blood cell count, a new infiltrate on chest x-ray, and a positive respiratory culture in a ventilated patient. Variables included demographics, injury, admission CCT, and culture data. We compared BDC-positive and BDC-negative patients.

Results: There were 33 cases of VAP in 94 study patients (35.1%), in whom the incidence of intracranial pressure (ICP) monitoring (66.7% versus 39.3%; P = 0.011) was significantly increased. Ventilator-associated pneumonia was significantly increased in the 28 patients (29.8%) in the BDC-positive group (16 [57.1%] versus 17 (25.6%); P = 0.004). Bilateral dependent consolidation independently predicted VAP. In the 33 VAP cases, gram-negative organisms were present in 27 patients (81.8%), with a predominance of Enterobacteriaceae (16 patients [48.5%]). Culture results did not significantly differ between the early (<4 d) versus late or BDC-positive versus BDC-negative VAP groups.

Conclusions: Ventilator-associated pneumonia is common after STBI, and BDC is independently associated; however, there is no predilection for specific organisms. Admission CCT findings may prove useful in identifying a group of STBI patients at higher risk for VAP.