Evaluation of the distance between the xiphoid process and the umbilicus: Is it appropriate for the measurement of the umbilical venous catheter length?

Abstract

Objective: Umbilical venous catheter is a commonly used intervention for total parenteral nutrition, antibiotic therapy, and investigations, especially in very low birth weight infants hospitalized in neonatal intensive care units. Catheter length can be calculated using several methods such as Dunn's method, Shukla–Ferrara's formula, and revised Shukla's formula. In this study, we evaluated with echocardiography whether the length of umbilical venous catheter inserted by measuring the upper limit of the xiphoid process and the lower limit of the umbilical ring is appropriate.Materials and Methods: A total of 12 premature infants with a birth weight ≤1500 g with umbilical venous catheter inserted were included in the study. The length of the umbilical venous catheter was determined by measuring the distance between the upper limit of the xiphoid process and the lower limit of the umbilical ring. Evaluation was performed first by chest X-ray followed by echocardiography. Results: On chest X-ray, the tip of the catheter appeared longitudinal below the diaphragmatic level in all infants. In none of the cases was the umbilical venous catheter found intracardiac when evaluated by echocardiography. The catheter tip was localized in the cavoatrial junction in four infants, thoracic inferior vena cava in five infants, and ductus venosus in three infants. Conclusion: In our study, we found that the length of umbilical venous catheter determined by measuring the distance between the upper limit of the xiphoid process and the lower limit of the umbilical ring did not lead to overadvancement, and this method can be used in practice. However, further studies with larger series are needed to draw more definitive conclusions on this issue.