In hypovolemic shock, the body compensates through the sympathetic nervous system. The earliest and most sensitive sign is tachycardia (pulse >100 bpm), as baroreceptors detect falling cardiac output and trigger compensatory heart rate increase before blood pressure drops significantly.

The progression of signs in hypovolemic shock:

1. Tachycardia (earliest)
2. Anxiety, restlessness
3. Decreased pulse pressure
4. Hypotension (late sign — indicates severe loss)
5. Decreased urine output (oliguria)
6. Cold, clammy skin, altered consciousness (late/severe)

As a Charge/Head Nurse, recognizing early shock is critical. By the time BP falls, the patient has already lost approximately 30\% or more of circulating blood volume.