To analyze the safety of indwelling neonatal umbilical vein catheter (UVC) at high or low tip positions.

We retrospectively analyzed 155 neonates with indwelling UVC in Guangdong Women and Children Hospital from March 2015 to May 2016. According to the position of the catheter tip, these infants were divided into high position group (the tip was at the same level as the central vein) or low position (the tip was below the portal vein) group. Several parameters including indwelling time, liver function, liver B-ultrasound and catheter-related bloodstream infections in the two groups were analyzed. Data were statistically analyzed using Mann-Whitney U test, Wilcoxon signed rank sum test or Chi-square test.

(1) A total of 155 infants were enrolled in this study. Their gestational age ranged from 25 to 41 weeks and their birth weight were 700 g to 4 690 g. UCV was inserted at the age of 0.5-8.0 d for 0-12 d. In the low position group, seven cases ended in early extubation due to fluid extravasation caused by shallow insertion. The indwelling time of the low position group was shorter than that of the high position group [M (P₂₅-P₇₅), 6 (4-7) d and 7 (5-7) d, Z=-2.580, P=0.010]. There were no significant differences in gender, gestational age, birth weight, and age at catheterization between the two groups. (2) No abnormality in the two groups was revealed by liver ultrasound. Complications such as neonatal necrotizing enterocolitis, thrombosis and embolism, air embolism and liver abscess were not reported. The proportion of liver function abnormalities in the high group was 6.9% (6/87), which was not statistically significant as compared with 4.4% (3/68) in the low position group (χ²=0.431, P=0.512). (3) Blood culture was performed for all cases, of which 116 (74.8%) were catheter culture (including 71 in the high position group and 45 in the low position group). The incidence of catheter-related bloodstream infection in the high position group was 5.6% (4/71) and the infection rate was 7.4 per thousand catheter days, while in the low position group these figures were 6.7% (3/45) and 8.0 per thousand catheter days, respectively. There was no significant difference between the two groups (χ²=0.052, P=0.820). (4) Results of catheter culture showed that seven cases were positive, including three for Staphylococcus haemolyticus (two in low position group and one in high position group), one for yeast-like fungus (high position group), one for Enterococcus faecium (high position group), one for Staphylococcus aureus (high position group) and one for Candida albicans (low position group).

The indwelling time of UVC at high tip position is longer than that at low position, and although there are no differences between the complications and the incidence of catheter-related bloodstream infection in the two groups, but its safety needs further study.

Umbilical veins; Catheters, indwelling; Time; Infant, newborn