Remote Ischemic Limb Preconditioning In Healthy Volunteers

Does Remote Ischemic Limb Preconditioning Improve Cerebral Vasomotor Reactivity in Healthy Volunteers?

The investigators would like to determine if remote ischemic leg preconditioning in healthy volunteers improves cerebral vasomotor reactivity as measured by breath holding and transcranial doppler vasomotor reactivity.

This study is to determine if remote ischemic leg preconditioning improves short and long term cerebral vasomotor reactivity in healthy volunteers as measured by breath holding and transcranial doppler vasomotor reactivity. Previous studies on brachial vasomotor reactivity have shown a beneficial effect of remote ischemic preconditioning. It remains uncertain if a similar beneficial effect can be reproduced with cerebral vasomotor testing. Many biological mechanisms and effector pathways triggered by preconditioning have demonstrated endothelial protection and beneficial vascular effects.

Either the right or left leg of the participant(s) will be made transiently ischemic for 5 minutes following by 5 minutes of rest. This will be repeated for 4 times.

Either the right or left leg of the participant(s) will be made transiently ischemic for 10 minutes following by 5 minutes of rest. This will be repeated for 3 times.

Either the right or left leg of the participant(s) will be squeezed without causing ischemia for 10 minutes following by 5 minutes of rest. This will be repeated for 3 times.

A blood pressure cuff is placed over the upper thigh of the participant(s) and inflated to 30 millimeters of mercury (mmHg) above systolic blood pressure. The loss of pedal pulses is confirmed by palpation. The cuff remains inflated for 5min and is followed by 5 minutes of reperfusion/rest. This will be repeated 4 times.

A blood pressure cuff is placed over the upper thigh of the participant(s) and inflated to 30 mmHg above systolic blood pressure. The loss of pedal pulses is confirmed by palpation. The cuff remains inflated for 10min and is followed by 5 minutes of reperfusion/rest. This will be repeated 3 times.

A blood pressure cuff is placed over the upper thigh of the participant(s) and inflated to 40 mmHg, sufficient to apply pressure but not affect blood flow. The presence of pedal pulses is confirmed by palpation. The cuff remains inflated for 10min and is followed by 5 minutes of rest. This will be repeated 3 times.

Inclusion Criteria: Healthy volunteers Exclusion Criteria: Presence of chronic medical conditions such as diabetes, hypertension, cardiac disease etc. Any prescribed medication Pregnancy [by history and last menstrual period] Any leg injury that would, in the opinion of the investigator, affect preconditioning