Impact of Subarachnoid Hemorrhage in Ventriculostomy-Related Infections Prospective Comparison of Two Neurosurgical Injury Contexts

BACKGROUND:Long thought to be immune privileged, the central nervous system (CNS) is far from being devoid of local immunity. Subarachnoid hemorrhage (SAH) and traumatic brain injury (TBI) represent two distinct CNS injury situations which, while both exposed to external ventricular drains (EVDs), present different incidences of ventriculostomy-related infection (VRI). We sought to compare VRI incidence and initial cerebrospinal fluid (CSF) inflammatory profiles in these two clinical situations. METHODS:From 2015 to 2020, 227 patients treated for SAH (193) or TBI (34) with an EVD were prospectively included. CSF samples were sent daily for microbiological examination, cell count, and biochemical analysis. VRI was defined as a positive CSF culture associated with CSF profile modifications and clinical signs. Ventriculostomy-related colonization (VRC) was defined as positive catheter culture at removal. Positive events were defined as VRI and/or VRC. RESULTS:Eleven patients suffered from VRI, with an incidence of 3.6 VRI per 1000 catheter-days. All VRIs occurred among SAH patients without a significant difference. Median duration of drainage was 12 [7 - 18] days, there were no significant differences for known VRI risk factors. Positive events were significantly higher in SAH patients (20.7 vs 2.9%, p=0.013). Inflammatory CSF markers and serum WBC were higher in SAH patients. CONCLUSION:Local inflammatory markers were markedly higher in SAH than in TBI. However, positive events were more frequent in SAH. Furthermore, SAH may be a risk factor for VRI. Hypothesis that a primary injury to the subarachnoid space could impair CNS immune functions should be explored.