Adverse lighting condition effects on the assessment of capillary refill

In 1989, Champion et al recommended revising the Trauma Score to exclude capillary refill because it is "difficult to assess at night. . . ." However, a literature search produced no studies evaluating the effect of lighting conditions on the assessment of capillary refill. This study was undertaken to determine if any such effect exists. Three hundred nine participants at an emergency medical services (EMS) seminar were asked to assess each others' capillary refill in both light and dark environments. The participants were nurses, emergency medical technicians (EMTs), and paramedics who had been instructed in the assessment of capillary refill. In daylight conditions (partly cloudy day, lux meter = 15 to 16), capillary refill was reported as normal in 94.2% of the participants, delayed in 1.9% of the participants, and undetected in 3.9% of the participants. In dark conditions (moonlight or street lamp, lux meter = 4 to 6), capillary refill was reported as normal in 31.7% of the participants, delayed in 1.6% of the participants, and undetected in 66.7% of the participants. chi 2 analysis demonstrated a statistically significant difference between capillary refill assessment in light versus dark environments (P < .001).