This study is testing a method called intravascular hypothermia for people with a recent neck spinal cord injury (SCI). Hypothermia means making the body cooler, and intravascular means it is done inside the blood vessels. The study will check if this cooling helps people recover better. Every year, many people in the US suffer from SCI, leading to serious problems like being unable to move or feel parts of their body. The study hopes that cooling can help them recover movement and sensation, making them more independent. This method could also help with other conditions like strokes or heart attacks in the future.

• **Duration:** Treatment must start within 24 hours of injury.
• **Participation:** Ages 18-70 with certain injury severity; cannot have serious other injuries, bleeding, or certain health conditions.
• **Benefits:** Potential for improved recovery and independence.