INTRODUCTION
Capillary refill time (CRT) is a simple and quick test requiring minimal equipment or time to perform. Prolonged CRT is a ‘red flag’ feature, identifying children with increased risk of significant morbidity or mortality.1–4 Although national and international guidelines, including National Institute for Health and Care Excellence guidelines, recommend the use of CRT as part of the initial assessment of unwell children,1,2 it is infrequently measured in general practice.5
WHAT DOES CRT MEASURE?
As there is no evidence for a relationship between CRT and blood pressure,6 CRT should not be used as a surrogate for blood pressure in children. There is, however, limited evidence to support a relationship between CRT and arterial blood flow, as well as other invasive cardiovascular parameters, such as superior vena cava oxygenation and core–peripheral temperature gap.6 Therefore, CRT is likely to have some value as a measure of peripheral perfusion.
HOW SHOULD CRT BE MEASURED?
The choice of site (for example, finger, hand, foot, or chest) at which CRT is measured can result in significantly different values. CRT can also be affected by the duration of pressure, and the ambient and skin temperatures, with longer duration of pressure and lower temperatures resulting in longer CRTs.6
The use of a timer to measure CRT is associated with greater …