Tourniquets Increase Proximal Pressure

There is an urgent clinical need to improve survival and neurologic outcomes after cardiac arrest. When a patient goes into cardiac arrest, cardiopulmonary resuscitation (CPR) with chest compressions is the current standard of care treatment to mechanically circulate blood through the patient's body. The immediate and long-term success of CPR is critically dependent on the maintenance of adequate coronary and cerebral perfusion. The investigators propose that CPR outcomes can be improved by capitalizing on the innate mechanism of vasoconstriction and preferentially routing the limited oxygenated blood to the heart and brain. The proposed solution is occlusion of extremity vasculature will increase coronary and cerebral perfusion and improve patient outcomes after cardiac arrest. Prior research has investigated the efficacy of manipulating peripheral vascular resistance with tourniquets in animal studies with improved cardiac and cerebral perfusion and survival. To prove this is an adequate solution in humans, the investigators plan to use tourniquets on the legs to occlude the peripheral vasculature in healthy humans and measure more proximal blood pressure before and after tourniquet deployment. Proof of concept of this solution will make way for development of novel devices for use during cardiac arrest and CPR to improve heart and brain perfusion and ultimately improve cardiac arrest outcomes. The investigators will recruit 30 healthy human participants and measure their blood pressure in their arm. They will then place two commercially-available, FDA-approved tourniquets around each thigh to stop blood flow to the legs. The investigators will measure the blood pressure in the arms again. They will then release the tourniquets after blood pressure measurement. This will be repeated three times with breaks between each repetition.