Determination of umbilical catheter placement using anatomic landmarks

Background: The placement of umbilical catheters is an essential part of initial newborn resuscitation and stabilization in the delivery room and later in the neonatal intensive care unit. While a variety of calculations have been derived based on patient morphometrics to determine the insertional length of the catheters, these equations remain inexact.

Objective: To determine a new method to calculate umbilical catheter insertion length using the anatomic pathway of catheters on lateral radiographs.

Methods: This was a retrospective study of infants who had umbilical catheters placed in our institution based on a diagnostic imaging database from 2004 to 2007 for all lateral abdominal and corresponding chest radiographs with umbilical vein and/or artery catheters in neonates. From a total of 82 umbilical venous catheter (UVC) and 55 umbilical arterial catheter (UAC) radiographs, the anatomic pathways were traced using Sigmascan Pro v4.0 software. An equation was derived for both UVC and UAC lengths that best approximated the traced length.

Results: The UVC length could be a simple measurement from the umbilicus to the mid-xiphoid-to-bed distance, measured on the lateral aspect of the abdomen (r(2) = 0.90). The UAC length was approximated by the following regression equation: 1.1 × (xiphoid-ASIS + umbilicus-ASIS) + 1.6, where ASIS is the anterior superior iliac spine (r(2) = 0.94).

Conclusions: Anatomic path-based calculations of umbilical catheters can accurately predict radiographic measured lengths. Prospective studies to validate this method against actual inserted length are required before promoting this approach.