A Study of the Comparison of Uitrasonography with Radiography to Localize the Umbilical Venous Catheter in the Neonate

Choi, Byoung Min; Yoon, Jae Kyun; Shon, Hyung Joo; Yoo, Kee Hwan; Hong, Young Sook; Lee, Joo Won; Kim, Soon Kyum

Abstract

PURPOSE: Incorrect umbilical venous catheter(UVC) position results in an increased incidence of complications and rnisleading pressure measurements. Most modern catheters are radiopaque and are easily seen on plain film radiographs but the exact relation of the catheter tip to vascular anatomic landmarks is not available. We assessed the ability of ultrasonography to locate the tip of UVC. And we described the relationship between the locations of the tip of UVC on the ultrasonography and the anatomical landmark seen on the radiography.
METHODS
From February 1997 to June 1997, 40 newborns admitted to NICU at Guro Hospital, Korea University, and required UVC insertion for clinical care. UVC position was checked by anteroposterior and cross table lateral radiography. And then ultrasonographic assessment was performed using Hewlett Packard Sonos-1000(Hewlett Packard, UK) with a 5 MHz transducer. The ultrasonographic examinations were documented on hard copy and compared with current plain film radiographs. The sensitivity, specificity, positive predictive value, negative predictive value for the radiography as a test to detect properly positioned UVC were calculated. RESULTS: 1) In 23 of 40 newborns the UVCs were properly positioned by anteroposterior radiography (T8-T10), but ultrasonographic examination showed that 3 UVCs were malpositioned(false positive value 13%). Detection of properly located UVC by anteroposterior radiography had a sensitivity of 76.9%, specificity of 78.6%, positive predictive value of 87% and negative predictive value of 64.7%. 2) In 13 of 40 newborns the UVCs were properly positioned by anteroposterior radiography (T8- T9), ultrasonographic examination showed that all UVCs were positioned in RA and IVC(false positive value 0%). Detection of properly located UVC by anteroposterior radiography had a sensitivity of 50%, specificity of 100%, positive predictive value of 100% and negative predictive value of 51.9%. 3) In 18 of 40 newborns the UVCs were properly positioned by cross table lateral radio- graphy(less than 7mm between diaphragm and tip of UVC), but ultrasonographic examination showed that all UVCs were positioned in RA and IVC(false positive value 10.5%). Detection of properly located UVC by cross table lateral radiography had a sensitivity of 69.2%, specificity of 100%, positive predictive value of 100%, negative predictive value of 63.6%. CONCLUSION: Ultrasonographic catheter localization is a noninvasive technique that uses no ionizing radiation and has no known deterimental side effects, and allows direct visualization of the pertinent vascular anatomy and provides more information than traditional radiography. Use of ultrasonographic guidance at the time of UVC insertion allows the catheter position to be immediately adjusted, with confirmation of the amended position, obviating the need for repeated radiological evaluations. When ultrasonography is unavailable, proper placement of UVC can be estimated by use of radiography to position the tip of UVC between the eighth and ninth thoracic vertebral body by anteroposterior radiography and less than 7mm above or below the diaphragm by cross table lateral radiography.