Which finding is an early sign of shock in a dog?

• A. Decreased heart rate
• B. Increased heart rate and capillary refill of 1-2 seconds
• C. Capillary refill of 3+ seconds with pale membranes
• D. Normal body temperature

Answer: (B)

In shock, the body first responds to reduced perfusion by trying to keep blood flowing to the vital organs. The heart rate increases as a compensatory mechanism to boost cardiac output. Capillary refill time is a quick window into peripheral perfusion; in the early stage of shock, perfusion to the extremities is still relatively adequate, so capillary refill is typically within the normal range or only mildly delayed (about 1–2 seconds). Seeing both a faster heart rate and a capillary refill in the 1–2 second range fits the early compensatory phase, before marked peripheral hypoperfusion develops.

A decreased heart rate would be atypical early on, since the body usually ramps up sympathetic activity to maintain pressure and flow. A capillary refill time of 3+ seconds with pale membranes signals more advanced shock with significant poor perfusion. Normal body temperature alone isn’t a reliable indicator of shock, because temperature can vary and may not reflect perfusion status in the early stage.