What is the immediate treatment for a casualty with a suspected spinal injury?

The immediate treatment for a casualty with a suspected spinal injury focuses on the stabilization of the spine and the avoidance of any movement. This approach is critical because even minor movements can exacerbate the injury, potentially leading to further damage to the spinal cord or surrounding structures.

Stabilization can involve manually holding the head and neck in alignment with the spine to prevent any rotation or flexion. This is often referred to as "spinal immobilization" and is essential in preserving neurological function and minimizing the risk of paralysis.

The other options, while important in various aspects of patient care, do not address the immediate need to protect the spine in a suspected spinal injury scenario. For instance, although performing a rapid assessment of vital signs is important, it does not prioritize the stabilization of the injury. Similarly, administering pain relief or inserting an intravenous line may be necessary later but should not precede the critical step of immobilizing the spine to ensure the casualty's safety.