Ventriculostomy – Related Infections: Prognosis and Diagnosis in the Neurosurgical Intensive Care Unit

Abstract

External ventricular drains (EVDs) are commonly used in the management of acute neurological injury. Ventriculostomy – related infection (VRI) is a common complication associated with the presence of EVDs. Despite how common VRI is reported to be, there is minimal data regarding how a diagnosis of VRI affects long term outcomes in patients with EVDs. This is due to heterogenous and poorly validated diagnostic criteria for VRI, and confounding from the primary neurological diagnosis.

This thesis contains three studies which attempt to address some of the gaps in the literature on VRI. Firstly, we performed a systematic review to assess the relationship between a diagnosis of VRI and clinical outcomes. We found that a diagnosis of VRI was not associated with increased mortality, and had no adverse effect on functional neurological outcome. Secondly, we performed a study of registry data to assess the association between VRI and clinical outcomes, and found that a diagnosis of VRI was not associated with poor functional neurological outcome or mortality. VRI was associated with increased ICU and hospital length of stay, and increased insertion of VP shunts. Finally, we performed a prospective study using 16S rRNA PCR to assess whether standard diagnostic methods for VRI were adequate. We found a low incidence of positive PCR, which correlated best with CSF culture results. We also found no cases of “culture-negative VRI”, and that in patients with no microbiological evidence of VRI, the incidence of abnormal CSF findings was high.

These studies suggest that a diagnosis of VRI as defined by standard diagnostic criteria may not affect mortality or functional neurological outcome. It also shows that VRI is likely overdiagnosed and therefore overtreated. Future research with multi-centre cohort studies would help to establish a more accurate definition of VRI, to help better direct treatment and prevention strategies.