Should We Consider Revising the Cutoff Value of Capillary Refill Time in Healthy Neonates?

Dhairya Bimal Gandhi, Pareshkumar Amrutlal Thakkar, Niyati Parmar

Abstract

Background: Capillary refill time (CRT) is a widely accepted method to assess peripheral perfusion in neonates. Though CRT has been used in clinical practice for many years, its clinical use was not preceded by detailed clinical research.

Aims: To evaluate the normative data for CRT and factors affecting CRT, and to find out the upper cutoff value of CRT in healthy neonates

Materials and Methods: This study included 300 stable neonates (156 male and 144 female), born at 32 to 42 weeks’ gestational age (GA). In each neonate, the CRT was assessed over the chest, at room temperature and under the warmer, on day 1 of life, and again between days 2 and 3. The CRT was recorded using a camera to observe the skin color, and the timing was accurately measured using video editing software. Paired t test, unpaired t test, and ANOVA were used for the analysis of quantitative variables. P < .05 was considered significant at 95% confidence interval (CI).

Results: We had a total of 1,118 CRT readings from the 300 neonates. The mean and 95% CI CRT values at room temperature were 1.53 seconds and 1.88 seconds, respectively. The mean CRT value was significantly shorter under the warmer (1.23 s; P ≤ .0001). The mean CRT value in euthermic neonates was significantly shorter compared with that in hypothermic neonates (body temperature < 36.5°C; P ≤ .0001). Other factors that affected CRT were birth weight, GA, and size for GA.

Conclusions: The mean CRT value at room temperature was 1.53 seconds, and at the 95% CI, the mean CRT value was 1.88 seconds. The common upper cutoff value of CRT can be taken as 2 seconds. CRT is affected by body temperature, use of the warmer, birth weight, GA, and size for GA.