The good positioning of the VCKT is essential for the security of the procedure. We made the hypothesis that the localisation of the VCKT tip is widely influenced by the position (flexion-extension) of the limb in which the catheter is introduced, and that echographic assessment of VCKT position allows an elective positioning.

Population: 45 premature newborn who need catheterisation procedure were prospectively enrolled: BW (mean ± SD) = 1147 g ± 312, Lenght = 38,4 cm ± 3,4, post natal age 12 d ± 13.

Materiel & methods: We used a silastic small diameter (0.6 mm OD) catheter (Neocath, Vygon). The VCKT position is assessed by echography(Apogee CX, Interspec), the VCKT is held when its tip is at the junction of the vena cava and the right atrium and even when the catheterized limb is half-bent. Once the VCKT has been held, we measured the distance from the catheter tip and the right atrium when the limb was completely outstretched and when it was completely bent.

Results: 48 catheterisations procedures were performed, 25 in the upper limb and 23 in the lower limb. The echographic positioning of the VCKT was successful every time. The catheter position is strongly influenced by the catheterized limb position: the distance between the positions of the catheter tip when the limb is outstretched or when it is bent is 22 mm± 7 (for example, this is equivalent to 4 vertebral intervals for a 1200 g neonate). This distance was wider when the lower limb is used: 26 mm± 5 vs 18 mm ± 7 (p = 0.0001)

The echographic positioning with the limb half-bent (which is the physiologic position) allowed an equilibrated situation between the two extreme limb position: the limb outstretched, the catheter tip was at the same distance of the entrance of the right atrium than when it was bent: 11 mm± 6 vs 11 mm ± 6.

Conclusion: The position of VCKT is strongly dependent on the catheterized limb position. The echographic assessment of VCKT position with the an half-bent catheterized limb allows an elective positioning, improving the security of the procedure.