The purpose of the study is to investigate if briefly stopping blood flow to the patient's
leg will lead to the patient's body being better able to tolerate possible decreased blood
flow to regions of the brain which otherwise frequently happens after subarachnoid
Previous studies show that various organs such as the heart, brain or kidney can tolerate
longer periods of decreased blood flow if prior to that insult shorter periods of decreased
blood flow were experienced.
Rupture of brain aneurysms is a common cause of death and disability, accounting for as many
as 10% of stroke cases in the United States. While much of the resulting injury to the
nervous system is caused by the initial bleeding from the aneurysm, many of these patients
develop cerebral vasospasm, pathological constriction of the blood vessels supplying the
brain, several days following hemorrhage. As many as a third of patients can suffer a
resulting neurological deficit and stroke, presumably caused by the decreased blood flow to
the brain (ischemia). This delayed brain injury accounts for a significant percentage of
poor outcomes following aneurysm rupture. Remote ischemic preconditioning by transient limb
ischemia (produced by inflation of a blood pressure cuff on the arm or leg) has been shown
to minimize ischemic injury to other organs, most notably the heart. This "remote ischemic
preconditioning" has the promise of protecting the brain from ischemic injury. Whereas in
other forms of stroke the onset of ischemia cannot be predicted in the general population,
following aneurysm rupture the investigators know patient's risk of developing vasospasm.
Therefore, ischemic preconditioning following aneurysm rupture may help prevent some of the
ischemic injury caused by vasospasm. One small study has shown decrease in vasospasm and
metabolic products of ischemia in patients treated with remote ischemic preconditioning
after subarachnoid hemorrhage. Decreased vasospasm due to remote ischemic preconditioning of
the brain following aneurysm rupture still needs to be validated and question remains if
that shows a mortality and morbidity benefit.
Remote Ischemic Preconditioning (RIPC) Procedure: Following enrollment, computer generated
randomization will be done to see if the patient gets RIPC or sham-RIPC procedure. Patients
will receive four cycles of lower limb remote ischemic preconditioning, starting at the
earliest post-hemorrhage day. The remote ischemic preconditioning will typically take place
on post-hemorrhage day 2 - 12. Each cycle of RIPC will consist of four 5-minute cycles of
lower limb ischemia followed by 5-minute periods of reperfusion. A large manual bedside
blood pressure cuff will be wrapped around the upper thigh of one leg. The cuff will be
inflated to a pressure 20 mm Hg greater than the systolic arterial blood pressure measured
by the patient's arterial line or upper limb blood pressure cuff. The adequate level of
inflation will be confirmed by the absence of pulse in the ipsilateral pedal artery as
detected by Doppler. The cuff will remain inflated for 5 minutes. The cuff will then be
deflated and the limb will be allowed to re-perfuse for at least 5 minutes. After the cuff
is deflated, the same procedure will then be repeated three times for a total of four
cycles. Patients receiving the sham-RIPC procedure will have the cuff inflated to a pressure
of 20 mmHg lower than systolic, hence to not occlude blood flow or cause ischemia. The rest
of the study will be conducted similarly in both groups. Research staff will be aware if the
patient is in the sham or treatment group. Patient, their nurse, treating physicians, lab
technicians and Transcranial Doppler (TCD) technicians will not be made aware if the patient
is receiving sham or treatment procedure.
Evaluation of Tolerance to the RIPC Maneuvers: The patient will be continuously monitored
for pain and discomfort during the RIPC session. If the patient pain is more than 6 in the
traditional 1-10 scale or if the patient expresses their desire to stop the maneuver, the
procedure will be stopped, and the data regarding number and duration of the maneuvers will
be recorded. A down-escalation of the treatment will be proposed, by reducing the number of
cuff inflations to 3 or 2, as tolerated.
Hemodynamic evaluation of the effect of RIPC Maneuvers: Intracranial pressure (if bolt or
external ventricular vein (EVD) present), blood pressure, oxygen saturation and heart rate
will be monitored through the pre-conditioning process. If heart rate or BP changes greater
than 20% of baseline and cannot be attributed to anything else the preconditioning will be
stopped and allowed to normalize before retrying or be aborted based on bedside nurse,
physicians, or research staff discretion. Oxygen saturation will also need to be above 92%
at all times and ICP<20 when starting or at discretion of the bedside nurse or physician.
Glascow Coma Score (GSC) will be monitored by nursing staff and recorded per ICU protocol.
(TCD) measurements will be performed per ICU protocol.
Clinical assessments of the patients will be performed daily and at discharge from the ICU
as per protocol. Modified Rankin Scale will be performed by research staff on arrival, Day
14, discharge, and by telephone at 1 and 6 months.
Data gathered from patients' chart will include location of aneurysm, interventions
performed, Hunt & Hess score, Fisher grade determined by CT-head, PT/PTT/INR, chemistries
and CBC (standard of care labs). Also information regarding ICU length of stay, hospital
length of stay, Transcranial Doppler measurements, GCS during stay, mortality and
demographics data will be gathered (includes age, sex, race, prior to admission Rankin
1. > 18 years of age
2. Diagnosis of recent aneurysmal subarachnoid hemorrhage
1. Patients with a known history of lower limb vascular disease, lower limb vascular
bypass surgery and/or peripheral neuropathy