Size of internal jugular vs subclavian vein in small infants: an observational, anatomical evaluation with ultrasound.

BACKGROUND

The primary goal of this study was to compare the size and depth of the internal jugular vein (IJV) and the subclavian vein (SCV) in infants under general anaesthesia. A secondary goal was to determine the correlation of weight, height, head circumference, and age to the size and depth of these veins.

METHODS

Sixty small infants weighing from 1.4 to 4.5 kg were included. Using ultrasound, the diameters via short-axis (SAX) and long-axis (LAX) views, cross-sectional area (CSA), and depth of the left and right IJV and SCV were measured.

RESULTS

The diameter of the IJV was 7.9% larger on average than that of the SCV as measured via the SAX and LAX views (mean: 3.1 vs 2.9 mm; Wilcoxon's signed-rank test: P<0.01). The CSA of the IJV was 27% larger on average than that of the SCV (mean: 10.2 vs 8.0 mm(2); Wilcoxon's signed-rank test: P<0.01). Seventy-five per cent of the neonates showed a larger CSA of the IJV. The SCV was 8.4% deeper on average from the skin surface than the IJV (mean: 6.4 vs 5.9 mm; Wilcoxon's signed-rank test: P<0.01). There was a significant positive correlation between weight, height, head circumference, and age to the size and depth of the veins (Spearman's rank correlation: P<0.01).

CONCLUSIONS

Because of its most likely larger size, the IJV can be recommended as the better choice for cannulation in comparison with the SCV. However, other factors should also be considered.