What measurement is obtained in an anesthetized dog, when you apply finger pressure on the gums for one second and then release this pressure?

• A. Blood pressure
• B. Blood oxygenation
• C. Capillary refill time
• D. Hydration status

Answer: (C)

Capillary refill time is the quick assessment of peripheral perfusion. By pressing on the gums for about one second, you blanch the capillaries; when you release, the time it takes for the color to return equals the capillary refill time. In anesthetized dogs, CRT helps gauge whether blood flow to the tissues is adequate. A typical normal CRT is under about 2 seconds; longer refill times can signal reduced perfusion from low blood pressure, poor cardiac output, or vasoconstriction from anesthesia. It’s not used to measure blood pressure directly (that requires a cuff or arterial line), nor to measure oxygenation (that requires pulse oximetry or a blood gas), nor to assess hydration status (which is evaluated by mucous membrane moisture, skin turgor, etc.). Therefore, the measurement obtained in this maneuver is capillary refill time.