This is being studied because intranasal insulin may be a way to prevent the brain injury that occurs after a cardiac arrest. Cardiac arrest is a life-threatening condition in which the heart suddenly stops beating and there is no blood flow to the body. If cardiac arrest is not treated immediately, it causes sudden death. Even when immediate treatment gets the heart beating again, many victims remain comatose and die later from brain injury. Nasal insulin, given immediately after a cardiac arrest may prevent or reduce brain injury. Nasal insulin reduces brain injury in animal experiments, and has been used to try to improve brain degeneration in patients with Alzheimer's disease. However, cardiac arrest patients may need higher doses than patients with Alzheimer's disease, therefore, this study is to examine those higher doses.
This study is to determine the safety and tolerability of regular insulin (Humulin R) when given intranasally (as drops in nostrils).~Healthy participants will be enrolled to determine the maximum tolerated dose of intranasal insulin.