Effect of External Ventricular Drain Versus Intraparenchymal Pressure Monitor Placement on Outcome After Severe Traumatic Brain Injury

Introduction: Indications for invasive intracranial pressure (ICP) monitoring are well established in traumatic brain injury (TBI) guidelines. However, the use of external ventricular drains (EVDs) or fiberoptic intraparenchymal monitors (IPMs) as first line monitoring devices is varied across institutions. Despite this, there are few studies that have been able to determine whether the type of monitor influences patient outcomes.  Here we compare outcomes in severe TBI patients treated with EVD and IPM.

Methods: A retrospective review was conducted at a level 1 trauma center from 2010-2019. One hundred and ninety-five patients > 18 years-of-age with severe TBI requiring invasive ICP monitoring were included. Patients who underwent craniotomy/craniectomy prior to monitor placement were excluded. Primary outcomes included mortality, GOS-E, and decompressive craniectomy due to refractory intracranial hypertension (RICH). Univariate statistical analysis was conducted, and categorical and continuous variables were analyzed using the chi-squared and Mann-Whitney tests, respectively.

Results: EVD compared to IPM was not statistically associated with improved mortality (p=0.09), favorable outcomes (GOS-E >4) (p=0.19), decompressive craniectomy for RICH (p=0.37), or central nervous system infection (p=0.11). However, EVD placement was associated with increased instances of ICP elevation within the first week (p < 0.001), increased median length of stay in the intensive care unit (p=0.001), increased need for device revision (p=0.01), and decreased need for hyperosmolar therapy within the first week (p < 0.001). Finally, the EVD group had a higher proportion of patients with CT Marshall score 3-6 (41.3% vs. 23.1%, p=0.020).

Conclusion : Initial management of severe TBI with EVD was not associated with improved mortality, favorable outcome, or reduced need for decompressive craniectomy for RICH compared to IPM. However, EVD was associated with decreased hyperosmolar therapy. In our cohort, patients who were initially managed with EVD had radiographically more severe brain injury and basal cistern effacement, as captured by the CT Marshall score.