Simple Formula to Place Central Venous Catheter Tip at T6 After Surgical Cutdown in Neonates

Abstract

The objective of this paper was to develop a generally applicable formula to estimate correct catheter length after surgical cutdown in right internal jugular vein (RIJV) in neonates. The carina has been utilized as an anatomic landmark indicating superior vena cava-right atrium junction (SVC-RA) for the optimal placement of the central venous catheter (CVC) tip position. However, this landmark may not be accurate in neonates. Recent researches noted that the sixth vertebral body (T6) could better serve as a new landmark of SVC-RA in neonates and smaller children. We prospectively performed RIJV cutdown. For a controlled and reproducible surgical procedure, the venous entry site was consistently taken as the point where the omohyoid muscle crosses the RIJV. On intraoperative infantogram, the vertical distance between the venous entry site and T6 was measured and the catheter was inserted to this length. A linear regression model was investigated using the following variables to elicit the best prediction model for catheter length: gestational age, postconceptional age, birth weight, and weight at operation. Weight at operation best correlated with the measured CVC length (R2 = 0.916, P = 0.00), and the following linear equation was derived: estimated CVC length (mm) = 9 × [weight at operation (Kg)] + 30. There was no statistically significant difference between measured and estimated CVC length. With this formula, the optimal catheter length could easily be estimated when considering RIJV cutdown.