Simple measurements to place umbilical catheters using surface anatomy

Area of Science:

• Neonatal Medicine
• Pediatric Surgery
• Medical Device Placement

Background:

• Accurate placement of umbilical venous catheters (UVC) and umbilical arterial catheters (UAC) is crucial for neonatal care.
• Existing formulas for estimating catheter insertion length, such as those by Shukla and Wright, have limitations in accuracy across varying infant demographics.
• External anatomical landmarks offer a potentially simpler and more intuitive method for determining correct catheter length.

Purpose of the Study:

• To develop and validate a novel method using external anatomical landmarks for estimating the appropriate insertion length of umbilical catheters in neonates.
• To compare the accuracy of this new method with established formulas based on birth weight (BW).

Main Methods:

• A retrospective study included neonates undergoing UVC or UAC placement.
• Catheter positions were confirmed radiologically, with UAC tips between T6-T10 and UVCs at the diaphragm level.
• Final catheter lengths were compared to lengths estimated by Shukla/Wright formulas and four morphometric measurements: umbilicus-to-nipple (UN), umbilicus-to-midpoint of inter-mammary distance, umbilicus-to-xiphoid process, and umbilicus-to-symphysis pubis (USp).

Main Results:

• The UN-1 cm measurement accurately estimated UVC insertion length in 94% of cases, significantly outperforming the Shukla formula (57% accuracy).
• The UN-1 cm + 2 USp measurement accurately estimated UAC insertion length in 92% of cases, surpassing the Shukla formula (57% accuracy).
• This combined morphometric measurement also showed higher accuracy for very low BW infants (94%) compared to the Wright formula (68%).

Conclusions:

• Simple morphometric measurements, specifically UN-1 cm and UN-1 cm + 2 USp, provide superior accuracy in estimating umbilical catheter insertion lengths compared to traditional BW-based formulas.
• These external landmark-based methods are suitable for neonates across all birth weight categories.
• The findings suggest a more reliable and accessible approach to umbilical catheter placement in clinical practice.