Radiologic Localization and Lengths of Umbilical Artery Catheter to Major Aortic Branches Determined by Ultrasonography in Neonates

ABSTRACT

PURPOSE: Incorrect positioning of umbilical artery catheter (UAC) results in an increased incidence of complications and erroneous pressure measurements. We radiologically localized major aortic branches and calculated the length of catheter from umbilicus to celiac artery, renal artery and aortic bifurcation for optimal positioning of UAC. To determine the neonatal body measurement that best predicts optimal UAC lengths, we studied three commonly used parameters-birth weight (BW), total body length (TBL) and shoulder-umbilicus length (SUL). METHODS: Fifty one high type of UAC were routinely identified by sonographic scanning from the epigastrium in longitudinal projection and 42 low type of UAC from the flank in coronal projection. The distances from the catheter tip to the celiac artery, the renal artery and to the aortic bifurcation were measured by electronic calipers and were compared with the length of the catheter from umbilicus to the tip on the chest anteroposterior radiograph. RESULTS: The celiac arteries originated from T10-T12, renal arteries Ll-L2, and aortic bifurcations L3-L5. There was positive correlation between BW, TBL or SUL and the length of catheter to the celiac artery (r2=0.476, 0.749 or 0.753), to the renal artery (r2= 0.785, 0.847 or 0.720), and to the aortic bifurcation (r2=0.714, 0.809 or 0.747). CONCLUSION: Although any one of the three parameters can be used clinically, we prefer the TBL and SUL parameters for its reliability and usefulness in emergency settings. The use of a new distribution plot of origins of major branches and regression equations for calculation of the lengths may help deciding the optimal position of UAC.