Use of Brain Oxygen Tension Level and Cleaved-tau Protein to Detect Vasospasm After SAH

Rupture of a cerebral aneurysm causes subarachnoid hemorrhage (SAH). Blood in the
subarachnoid space of the brain can cause irritation of the cerebral blood vessels, leading
to constriction of these vessels, a phenomenon known.as vasospasm. Cerebral vasospasm can
cause stroke and possibly death. Of all the patients with SAH, approximately 20-40% will
suffer from clinical vasospasm and more than 60% of those patients will never get back to
their previous functional status. Tools to identify early vasospasm and thus early treatment
could greatly decrease the morbidity and mortality following SAH.

Cleaved tau protein is a neuronal marker that has been detected in blood and CSF of stroke
patients early in its time course. Since vasospasm can lead to stroke, the purpose of this
project is to determine whether increase in cleaved tau protein in blood and/or CSF can
predict early stroke from vasospasm. Changes in brain oxygen tension measured by a brain
tissue oxygen monitor and cerebral blood flow measured by CT perfusion will be correlated
with cleaved tau protein levels and clinical status. Utilizing statistical analysis the
levels of Cleaved tau protein, brain oxygen and blood flow during hospitalization will be
correlated with patient outcome. Through this study we hope to identify increase in cleaved
tau protein and decrease in cerebral blood flow and oxygenation as predictors of early
vasospasm. Early detection and treatment of vasospasm could decrease the stroke rate in SAH
patients and therefore be of great benefit to society.

Inclusion Criteria:

- Patients with subarachnoid hemorrhage

- Patients with external ventricular drains

Exclusion Criteria:

- Patients in whom consent is not attainable