Temporal Changes in CSF Cell Parameters After SAH: Comparison of Ventricular and Spinal Drain Samples

Forty percent of patients with aneurysmatic subarachnoid hemorrhage (aSAH) develop acute hydrocephalus requiring treatment with cerebrospinal fluid (CSF) drainage. CSF cell parameters are used in the diagnosis of nosocomial infections but also reflect sterile inflammation after aSAH. We aimed to study the temporal changes in CSF parameters and compare external ventricular drain (EVD)-derived and lumbar spinal drain-derived samples.

We retrospectively identified consecutive patients with aSAH treated at our neurointensive care unit between January 2014 and May 2019. We mapped the temporal changes in CSF leucocyte count, erythrocyte count, cell ratio, and cell index during the first 19 days after aSAH separately for EVD-derived and spinal drain-derived samples. We compared the sample sources using a linear mixed model, controlling for repeated sampling.

We included 1360 CSF samples from 197 patients in the analyses. In EVD-derived samples, the CSF leucocyte count peaked at days 4-5 after aSAH, reaching a median of 225 × 10⁶ (interquartile range [IQR] 64-618 × 10⁶). The cell ratio and index peaked at 8-9 days (0.90% [IQR 0.35-1.98%] and 2.71 [IQR 1.25-6.73], respectively). In spinal drain-derived samples, the leucocyte count peaked at days 6-7, reaching a median of 238 × 10⁶ (IQR 60-396 × 10⁶). The cell ratio and index peaked at 14-15 days (4.12% [IQR 0.63-10.61%]) and 12-13 days after aSAH (8.84 [IQR 3.73-18.84]), respectively. Compared to EVD-derived samples, the leucocyte count was significantly higher in spinal drain-derived samples at days 6-17, and the cell ratio as well as the cell index was significantly higher in spinal drain-derived samples compared to EVD samples at days 10-15.

CSF cell parameters undergo dynamic temporal changes after aSAH. CSF samples from different CSF compartments are not comparable.