What could indicate that a casualty with no vitals might regain consciousness?

The indication that a casualty with no vitals might regain consciousness is best reflected by the return of a radial pulse. A radial pulse signifies that there is blood flow reaching the extremities, suggesting that the heart is beginning to pump effectively and circulation is being restored. This is a critical sign during resuscitation, as it often indicates that vital organs may be receiving blood and oxygen, which is essential for consciousness and overall physiological function.

In contrast, while a reduction in heart rate may suggest some return of cardiac function, it does not guarantee the delivery of adequate blood flow to the brain or other vital organs needed for consciousness. Immediate resuscitation efforts, although vital, do not provide a definitive indication on their own if any signs of life will return, as success can vary based on numerous factors. The application of a splint, primarily used for immobilization and stabilization of fractures, does not directly influence consciousness or vitals; it is more focused on injury prevention rather than reviving lost physiological functions. Thus, the return of a radial pulse is the most direct indicator that consciousness might return in this scenario.