Predicting Depth of Pediatric Central Lines

To develop simple formulas to predict optimal insertion depth for left thoracic central venous catheters in children, investigators retrospectively measured left internal jugular and subclavian veins in 257 children (<13 years; median, 20 months) who underwent chest computed tomography angiography.

Vein lengths were measured along the path of standard central line placement, to the junction of the superior vena cava and the right atrium (the optimum termination point for the catheter tip); the left internal jugular vein was measured from the superior border of the left clavicle, the left subclavian vein from the anterior border of the left clavicle.

Based on these measurements, the investigators derived formulas for optimal insertion depth: 0.07 × height (cm) for the left internal jugular vein and 0.08 × height (cm) for the left subclavian vein. These formulas predicted correct vein lengths in 99% and 94% of the children, respectively. Optimal catheter depth for the right internal jugular vein was measured from the anterior border of the right clavicle, yielding a formula of 0.06 × height (cm), although this was not validated.