Association of Serial Ventricular Routine Cerebrospinal Fluid Findings with Complications and Outcome in Aneurysmal...

Cerebrospinal fluid (CSF) inflammation is frequently seen in patients with aneurysmal subarachnoid hemorrhage (aSAH) requiring an external ventricular drain. Its role as a physiological response to the extravasation of blood, as a driver of delayed cerebral ischemia (DCI) and chronic hydrocephalus, or as a marker of ventriculostomy-related infection remains controversial. This study explored the associations between longitudinal routine CSF parameters and the development of DCI, shunt-dependent hydrocephalus, and functional neurological outcome in a large aSAH cohort.

In this retrospective study, 702 samples from 169 patients with aSAH with at least three serial ventricular CSF samples from an external ventricular drain within the first 14 days after aSAH were included. Routine CSF parameters-that is, leukocyte count (CC) and erythrocyte count (EC), CSF lactate (LCT), and CSF/plasma glucose ratio-were considered. For bivariate analysis, values and time points of peak CC, EC, LCT, and trough CSF/plasma glucose ratio, respectively, and mean values in the early, middle, and late phase after aSAH were considered. For the analysis of longitudinal CSF parameter dynamics, generalized linear mixed-effects modeling was applied. Patients were compared according to the development of DCI, shunt-dependent hydrocephalus, and dichotomized short-term and long-term functional neurological outcome.

Longitudinal CC followed a nonlinear course over the first 14 days, with a peak around day 4 to day 8 after aSAH with a temporal relationship between peak CC and the occurrence of DCI. Higher initial EC with a more rapid decline was associated with favorable functional outcome, whereas persistently elevated LCT levels were seen in patients with unfavorable outcome. Patients with microbiologically confirmed ventriculostomy-related infection did not stand out significantly regarding CC absolute values or longitudinal dynamics.

Intrathecal inflammation during the first 14 days after aSAH with a peak around day 7 seems to be a physiological response to the extravasation of blood into the CSF space. In patients with favorable outcome, EC decay was more rapid, indicating a more efficient clearance of blood from the subarachnoid space.