Goal directed therapy (GDT) is a technique, which employs a non-invasive cardiac output monitoring (NICOM) device to guide management of circulating blood volume and blood pressure during procedures. The purpose of this study is to determine whether the use of goal-directed therapy to optimize blood volume and cardiac output during the procedure can improve the outcome of patients undergoing endovascular treatment of a brain aneurysm.

Subarachnoid hemorrhage (SAH) as a result of ruptured intracranial cerebral aneurysms is a life threatening condition; with an estimated incidence of 6-10 cases per 100,000 persons per year. Endovascular coil emobolization of the aneurysm is performed to isolate the aneurysm and reduce the risk of re-bleeding. Unfortunately, despite timely and successful intervention approximate 25% of post-coiling patients suffer immediate and/or long-term injury including death as a result of intracranial bleeding. This is mainly a consequence of subarachnoid hemorrhage-related complications , especially cerebral vasospasm. Angiographic vasospasm and symptomatic vasospasm occur in 30-70% and 20-30% of SAH patients respectively. Goal-directed therapy (GDT) provides a means to assess and manage circulating volume and cardiac output. In this study, the investigators would investigate the use of GDT during aneurysm coiling procedures can improve the clinical course of these patients.

This will be a blinded, randomized pilot study to compare clinical outcomes for endovascular coiling patients allocated to one of two treatments: GDT or non-GDT. Randomization consented patients will be randomized into GDT or non-GDT groups in 1:1 ratio. The attending anesthesiologists will not be blinded because of the nature of the intervention. However, surgeons, patients, outcomes assessors will be blinded as to the treatment intervention.

In all patients, an arterial catheter (routinely used in these patients) will be inserted and connected to the Flotrac (Edward Lifesciences). After transferring the patients into the angiogram suite, routine monitoring such as pulse oximetry, electrocardiography, non-invasive blood pressure monitoring, end-tidal CO2 and temperature probe will be attached to the patients. Anesthesia will be conducted in the standard fashion. Patients will be randomized into two groups in 1:1 ratio: GDT or non-GDT therapy.

• GDT group: the attending anesthesiologist will use the data obtained from the Flotrac to manage fluid and hemodynamics during the procedure following the prescribed treatment algorithm. The treatment interventions will start on induction of anesthesia and continue until the patients are extubated or transferred back to intensive care unit with mechanical ventilation.
• Non-GDT group: Flotrac will be connected but the machine values will be blinded to the anesthesiologist and interventionist. The screens of the Flotrac will be covered by opaque plastic bag and the alarms will be turned off. The attending anesthesiologist will make clinical decisions regarding the management of fluids and hemodynamics based on current individual routine practices.

Inclusion Criteria:

• All adult patients (age> 18 years of age) scheduled for aneurysm endovascular coiling procedures over the next 2 years.
• Grade I to IV SAH within 5 days of presentation will be included in the study.
• Only patients identified as appropriate by the neurosurgeon/neuro-radiologist will be recruited.

Exclusion Criteria:

- Patients with un-ruptured aneurysm(s)

• Patients with previous clipping or coiling procedure for the same aneurysm.
• Patients undergoing concomitant extracranial-intracranial bypass procedures or other non-neurosurgical procedures.
• Patients with giant aneurysm (size> 25mm)
• Pediatric patients (<18 years of age) or pregnant patients
• Unable to obtain informed consent from patients or substitute decision maker (SDM).