Pulsatile Perfusion Therapy Phase II

Individuals who suffer from a stroke, cardiac arrest, or traumatic bleeding (hemorrhage) injuries often have compromised blood flow and oxygen to the brain which can lead to the death of brain cells, and if the patient survives, subsequent difficulty in thinking and performing tasks of daily living. Traditionally, delivery of a constant flow of blood to the brain has been thought to be the most important factor for the survival of brain cells. In this study, a novel intervention will be assessed called "pulsatile perfusion therapy", delivering blood flow in a slow pulsing pattern. It is anticipated this intervention will improve brain blood flow and oxygenation during these serious clinical events. There is a specific interest in whether delivery of brain blood flow with a slow pulsatile pattern will improve oxygenation of brain tissue, particularly when the brain is challenged under low oxygen (hypoxia) and low volume (hypovolemia) conditions, simulating stroke, cardiac arrest, and hemorrhage. A technique called oscillatory lower body negative pressure (OLBNP) will be used in healthy human participants, facilitating delivery of blood flow to the brain with different pulsing patterns. This technique will allow for determination of the ideal pattern of brain blood flow that improves oxygenation of the brain tissue. Measurements will be made of substances in the blood that may be released with pulsatile flow which act on the blood vessels to increase flow and delivery of oxygen.