preconditioning for aneurismal subarachnoid hemorrhage

Conditions: Subarachnoid Hemorrhage

Summary: in remote preconditioning, ischemia in one organ protects distant organs from ischemic insults. e.g. brief induced limb ischemia protects the brain from an otherwise more severe stroke. the objective of this study is to determine if remote ischemic preconditioning can be safely and effectively instituted in patients with subarachnoid hemorrhage, who are at high risk for developing disabling cerebral ischemia. the investigators will also preliminarily assess if there is evidence for neuroprotection. this will be a phase 1b study. additional objectives are: 1. to determine if remote ischemic preconditioning can be safely and effectively instituted in patients with subarachnoid hemorrhage, who are at high risk for developing disabling cerebral ischemia. 2. analogously to a dose-escalation study the investigators propose to study the safety and tolerability of increasing durations of limb ischemia until a target time of 10 minutes of limb ischemia has been reached.

the investigators propose to study patients with subarachnoid hemorrhage, who generally have a high risk of ischemic stroke in the 2 weeks following the initial bleed, and patients with clipped or coiled aneurysm. the investigators will apply a blood pressure cuff around leg and use it to interrupt the circulation for 5-10 minutes. the investigators will repeat this for a total of 3 times every 24 to 48 hours up to 14 days. the cuff will be inflated for 5-10 minutes and then deflated for 5 minutes. there will be 3 cycles of this. the cuff will be inflated to 200mmhg. the investigators will first start with 5 minutes of cuff inflation to either the arm or leg. the investigators will determine if this is safe in at least 6 patients. the investigators will then increase the duration of cuff inflation to 7.5 minutes for another 6 patients. if no adverse events are noted the investigators will the proceed to study 10 minutes of inflation in another 6 patients. if no side effects are noted the investigators will then determine that this is well tolerated. the study will be monitored by a data safety monitoring board who will make decisions about escalating the duration of cuff inflation. if 2 or more patients develop an adverse event that is related to the procedure the investigators will stop and no longer continue at that level of cuff inflation and the previous level of cuff inflation will be determined to be the safe and tolerated level. the investigators will collect safety data on adverse events such as tolerability, local tissue trauma or deep vein thrombosis.

Eligibility criteria:
inclusion criteria: aneurismal subarachnoid hemorrhage exclusion criteria: 1. hunt hess scale \> 4 2. inability to undergo limb preconditioning due to local wound or tissue breakdown, history of peripheral extremity vascular disease or patient discomfort. 3. inability to obtain informed consent from the patient or a health care proxy. 4. ankle-brachial index \< 0.7 5. inability to start limb preconditioning within 4 days of bleeding.

Keywords: limb preconditioning remote preconditioning ischemic preconditioning