Ventilator-associated Pneumonia Predicts Acute Cognitive Disability in Severe Traumatic Brain Injury

Author(s):
Shruthi Srinivas; Christopher Gilliam; Jacob Roden-Foreman; Russell Payne; Anna Liveris; Anthony Tigano; Michelle Kincaid ; Stephanie Doris; William Brigode; Johanna Stecher; Katherine McBride; Tanya Egodage; Joy Song; Kaushik Mukherjee; Brett Tracy; Liz Liz Penaloza – Villalobos

Background:

Cognitive impairment is a common sequela of traumatic brain injury (TBI) and may be exacerbated by concomitant clinical factors.  Ventilator-associated pneumonia (VAP) is linked to poor outcomes in this population, yet its effect on cognitive disability is unknown.

Hypothesis:

We hypothesized that there would be an association between cognitive disability and VAP during the acute posttraumatic period in patients with a severe TBI.

Methods:

We performed a post-hoc analysis of a prospective, multicenter, observational study of adults with a severe (Glasgow coma score ≤ 8), blunt TBI at 8 US trauma centers from 2020 – 2023. We excluded patients who died during their hospitalization. Patients were grouped by whether they had VAP, which was defined as pneumonia and mechanical ventilation ≥ 48 hours. Our primary outcome was severe cognitive disability or worse, defined as a disability rating scale (DRS) score >13, at discharge and/or 28-days post-injury. Backward selection multivariate regression was performed using VAP and other clinically relevant variables to predict cognitive disability.

Results:

There were 309 patients in the cohort, of which 31.7% (n=98) had VAP. The VAP group had higher rates of diffuse axonal injury (DAI; 37.3 vs 22.3%, p=0.004), subarachnoid hemorrhage (82.7 vs 70.6%, p=0.024), neurosurgical interventions (63.3 vs 38.4%, p<0.001), tracheostomy (72.5 vs 28.9%, p<0.001), and neurostimulants (54.1 vs 28.4%, p<0.001). Median injury severity score was higher in patients with VAP (29 vs 25, p=0.007). Patients with VAP had longer length of stay (32 d vs 19 d, p<0.001) and duration of mechanical ventilation (13 d vs 3 d, p<0.001).  Of the VAP group, 72.5% required tracheostomies, median time to VAP diagnosis was 7 d [4, 12], time to tracheostomy was 10 d [7, 16], and time between the two events was 4 d [2, 11]. Higher proportions of severe cognitive disability (64.3 vs 19.9%, p<0.001) and higher (worse) median DRS scores (8 vs 2, p<0.001) were seen in the VAP group. On regression analysis, controlling for DAI, medical comorbidities, neurostimulants, neurosurgical intervention, and ventilator days, VAP was independently associated with severe cognitive disability at discharge (aOR 4.2, 95% CI 2.2-7.8).

Conclusions:

VAP is common among patients with TBI and independently predicts severe cognitive disability during the acute posttraumatic period. Adherence to VAP prevention techniques may help mitigate the cognitive impairment seen in this population.