Capillary refilling time in newborn babies: Normal values

Abstract

Aim - To assess the normal values of capillary refilling time (CRT) in healthy newborn babies; to assess the effect of different nursery containers (incubator, radiant warmer, crib), phototherapy, birthweight, gestational age, size for gestational age and sex on CRT; to compare CRT at different body sites as well as to assess the variation between observers. Methods - Healthy neonates (n = 469) of different gestational ages and different sizes for gestational age, were studied 1 to 7 days after birth. CRT was measured in four of the most suitable sites - namely, midpoints of the sternum and the forehead, the palm of the hand and the plantar surface of the heel (defined as chest, head, palm and heel, respectively). The applied pressing time was 5 seconds. CRT was measured with a manual stopwatch. Results - Only the chest and the head distribution curves followed the Gaussian curve. The mean values and standard deviation of CRT in all tested nursery containers, including phototherapy for the chest, ranged from 1.82 (0.34) seconds to 2.01 (0.423) seconds, and for the head from 1.59 (0.36) seconds to 1.83 (0.31) seconds. The mean value of chest CRT was always longer than the head CRT for all parameters. Significant differences were found between different nursery containers, receivers, and non-receivers of phototherapy and between observers. No difference was found between sex, birthweight, gestational age and size for gestational age. Conclusions - The upper limit of normal for neonatal CRT was 3 seconds. Nursery containers, phototherapy, and observers produced significantly different results, but the differences were not clinically important. CRT values of the midpoints of the sternum and the forehead are the most consistent.