1033. Blood clearing rate and need for ventriculo-peritoneal shunt in patients with a subarachnoid hemorrhage.

Authors: Athanasios Petridis, MD, IFAANS; Angelika Zhivotovskaya; Igor Fischer; Hans Jakob Steiger (Duesseldorf, Germany)

Introduction: After aneurysmatic subarachnoid hemorrhage blood disappears from the subarachnoid spaces in various rates from case to case. 30% of patients become hydrocephalic and need a ventriculo-peritoneal shunt. We studied the association between the wash out rate from the subarachnoid space and indication for ventriculo-peritoneal shunting. Methods: Retrospective study of N=227 patients with aneurysmatic subarachnoid haemorrhage Fisher 1-4 treated in our department from 2015-2017 (2 years). Cranial CT was performed on days 1, 3, 6, 9 and 12 after haemorrhage. We evaluated the CT for disappearance of blood in the subarachnoid spaces (basal and external) in the time periods 0-3, 4-6, 7-9 and 10-12 and >12 days (qualitative analysis with two parameters: no blood or blood). Other parameters analysed were, need for ventriculo-peritoneal shunting, external ventricular drain, endovascular or microsurgical treatment, vasospasms ventricular hemorhage, intracerebral haemorrhage and craniectomy. Results: Fisher grade 3-4 bleedings were significantly associated with hydrocephalus compared to Fisher 1-2 bleedings. A faster wash out rate was significantly associated with less incidence of hydrocephalus( 5 vs 7 days). Ventricular haemorrhage was associated with a significantly higher rate of hydrocephalus and shunting. In patients with hydrocephalus (indication for shunting or external drain) the time of wash out between basal and peripheral blood was significantly increased (6 days vs 4 days). Conclusion: The wash out rate of blood in the basal cysterns and the external (peripheral) subarachnoid spaces is significantly associated with hydrocephalic states in patients with subarachnoid hemorrhages Fisher grade 3 and 4. The longer the blood stays in the subarachnoid spaces and the greater the time difference between washout from the basal cisterns and the peripheral CSF space is, the greater the incidence of hydrocephalus after subarachnoid haemorrhage and need of ventriculoperitoneal shunting. Intraventricular haemorrhage significantly increased the risk of shunting.