Cerebrospinal Fluid Drainage Trajectories Are Associated With Ventriculoperitoneal Shunt Placement After Aneurysmal...

Predicting the need for ventriculoperitoneal shunt (VPS) placement after aneurysmal subarachnoid hemorrhage (aSAH) remains challenging, particularly among patients requiring prolonged external ventricular drainage (EVD). Existing predictors largely rely on static clinical or radiographic features and may not capture how cerebrospinal fluid (CSF) drainage evolves over time. We evaluated whether longitudinal CSF drainage trajectories, adjusted for EVD height, were associated with VPS placement after aSAH.

We performed a retrospective analysis of a prospective multicenter observational study of 149 adults with aSAH treated with EVDs at 6 US neurocritical care centers. Daily CSF drainage volume, EVD height, time from EVD placement, and VPS placement were analyzed using mixed-effects modeling to assess differences in CSF drainage trajectories over time.

Thirty-four patients (22.8%) underwent VPS placement. Patients who underwent VPS placement had longer EVD duration and higher average daily and total CSF drainage during hospitalization. In longitudinal models adjusted for EVD height, CSF drainage trajectories diverged over time. Divergence emerged after day 8 from EVD placement, with CSF output declining more rapidly in patients who did not undergo VPS placement, whereas drainage remained more sustained in patients who underwent VPS placement. By day 18, height-adjusted CSF drainage was significantly higher among patients who underwent VPS placement. Among patients with EVD drainage for 18 days or longer, fewer than half underwent VPS placement, highlighting persistent uncertainty in this clinically challenging subgroup.

Longitudinal CSF drainage trajectories, adjusted for EVD height, were associated with VPS placement after aSAH. Differences in CSF drainage trajectories emerged after day 8 and became more pronounced during prolonged EVD management. These findings suggest that longitudinal CSF drainage trajectories may complement static clinical and radiographic predictors in future shunt prediction models and studies of EVD weaning.