Which of the following is a sign of shock in a casualty?

The presence of a weak or rapid pulse is a sign of shock in a casualty. During shock, the body goes into a state of compensation to maintain vital functions. When blood volume decreases due to trauma or other causes, the heart works harder to circulate whatever blood is available, leading to an increased heart rate. Additionally, because the blood flow to the extremities may decrease as the body prioritizes blood supply to vital organs, the pulse may feel weak or thready.

In contrast, options that indicate increased blood pressure, normal skin color, or a steady respiratory rate do not align with the physiological responses typical of shock. In fact, blood pressure typically decreases in shock as the body's compensatory mechanisms fail, skin may appear pale or gray due to poor perfusion, and the respiratory rate often increases as the body attempts to compensate for decreased oxygen delivery. Understanding these vital signs is crucial for assessing a casualty's condition and providing appropriate care in emergency situations.