Which clinical sign best evaluates tissue perfusion?

• A. Capillary refill time
• B. Mean pulse pressure
• C. Systolic blood pressure
• D. Heart rate

Answer: (B)

Evaluating tissue perfusion is best done by signs that reflect how well blood is reaching the tissues, especially at the microvascular level. Capillary refill time directly gauges peripheral perfusion: after blanching a nail bed or a small area of skin, the speed with which color returns tells you how effectively blood is flowing to the tissues. In neonates, a refill time longer than about 2 seconds suggests reduced perfusion and potential shock or dehydration, making it a sensitive bedside indicator.

Mean pulse pressure, the difference between systolic and diastolic pressures, does not measure tissue perfusion directly. It reflects aspects of cardiac function and arterial tone, but it can be influenced by many factors and may not accurately indicate how well tissues are being perfused at the moment. Systolic blood pressure and heart rate can be variable and compensated in early distress, so they’re less reliable on their own for assessing perfusion.

So, capillary refill time is the most informative single clinical sign for evaluating tissue perfusion at the bedside.