Capillary Refill Time (CRT)

Capillary Refill Time (CRT) is a quick assessment of circulatory health (perfusion). It measures how long it takes for colour (blood) to return to tissue after pressure is applied. This can help identify shock, dehydration, or poor circulation.

How to Check Capillary Refill Time:

1. Find the gums: Gently lift your pet's upper lip to expose the gums above the teeth.
2. Apply pressure: Press your finger firmly against the gum until it turns white (blanches).
3. Release and count: Remove your finger and count how many seconds it takes for the area to return to its normal pink colour.
4. Assess the result: Normal CRT is less than 2 seconds.

Interpreting Capillary Refill Time:

• Less than 1 second ("flash CRT"): May indicate early shock, high blood pressure, excitement, or fever.
• 1-2 seconds: Normal
• More than 2 seconds (prolonged CRT): Poor perfusion, indicating possible shock, severe dehydration, or heart failure. Requires urgent veterinary attention.

Other Observations (Mucous Membrane Colour & Moisture):

• Colour: Should be pink.
  • Pale/white gums: Anaemia, shock, blood loss.
  • Bright red gums: Sepsis, heat stroke, carbon monoxide poisoning.
  • Blue/purple gums (cyanosis): Lack of oxygen. Critical emergency.
  • Yellow gums (jaundice): Liver disease, destruction of red blood cells.
  • Brown gums: Paracetamol toxicity (esp. cats).
• Moisture: Should be moist and slippery. Tacky or dry gums indicate dehydration.