Low positioning of umbilical-artery catheters increases associated complications in newborn infants.

We performed a randomized prospective study of the effect of placement position of umbilical-artery catheters on complication rates in high-risk newborn infants. A higher complication rate (31 of 40 vs. 13 of 33) (P less than 0.005) occurred in the group with the catheter tip at the third to fourth lumbar segment, as compared to those with the tip at the seventh to eighth thoracic segment, owing to more episodes of blanching and cyanosis of the extremities. There was no difference between groups in the rate of complications requiring catheter removal. Aortography revealed thrombosis in 21 of 23 patients studied, but there was no clinical evidence of impaired circulation. In retrospect, we found that, independently of catheter position, administration of antibiotics through the catheter was associated with an increased rate of complications (63 vs. 20 per cent). Umbilical-artery catheterization entails potential risks regardless of the position of the catheter; placement of the catheter with its tip at the seventh to eighth thoracic segment may be associated with fewer complications than at lower positions.