Low positioning of umbilical-artery catheters increases associated complications in newborn infants. Randomized trial of umbilical arterial catheter position: clinical outcome. Efficacy of thromboresistant umbilical artery catheters in reducing aortic thrombosis and related complications. Umbilical artery catheters: high, low, or no. Effect of heparin infusates in umbilical arterial catheters on frequency of thrombotic complications.
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. In order to determine if umbilical arterial catheter position affects the incidence of necrotizing enterocolitis, clinical outcome was analysed in 308 infants whose umbilical arterial catheter had been randomly allocated to a high (n = 162) or a low (n = 146) position. Necrotizing enterocolitis was classified as suspected or confirmed; all renal, lower limb and local catheter complications were also recorded. High umbilical arterial catheters were in place for longer than low catheters, provided more samples and were removed as an emergency less often. Lower limb blanching and cyanosis were more common with low catheters. Eleven cases of confirmed necrotizing enterocolitis occurred in the "high" group and nine in the "low" group. One case of fatal aortic thrombosis was encountered in the high group. Positioning umbilical arterial catheters in a high position allowed longer functional use and did not increase the incidence of necrotizing enterocolitis. Previous in vitro and in vivo reports suggest that catheters constructed of polyurethane with heparin bonded to the surface (HB-PU) are less thrombogenic than catheters made of polyvinyl chloride (PVC). A randomized trial sufficiently large (power 80%) to detect a reduction in the incidence of umbilical artery (UA) catheter complications, including aortic thrombus formation, from 45% to 20% was conducted in 125 infants. The infants were monitored for complications possibly related to the use of a UA catheter, such as systemic hypertension and abnormalities of lower extremity perfusion. The presence of aortic thrombi was assessed by ultrasound study 3.5 +/- 1.2 (SD) days and 11.1 +/- 2.3 days after insertion of the catheter. The use of HB-PU umbilical catheters did not lead to a significant reduction in the incidence of complications and aortic thrombi compared with the use of PVC catheters. The lack of reduction may have been related to the prolonged duration of catheter use in both groups. A much larger study would have been required to detect a smaller, but perhaps clinically significant, reduction in catheter-associated complications. nan We studied 111 infants requiring an umbilical artery catheter, 59 with heparin and 52 without. Thirty-four thrombi were detected, 16 in the heparin group and 18 in the control group. The numbers of thrombi in the two groups was not significantly different, but the number of clotted or nonfunctioning umbilical artery catheters was greater in the control group (P less than 0.05), as was the incidence of hypertension (P less than 0.05). There were no other significant differences between the two groups. We conclude that the use of low doses of heparin may not change the incidence of umbilical artery catheter-related thrombi, but it does appear to lower the incidence of their sequelae.
There appears to be no evidence to support the use of low placed umbilical artery catheters. High catheters should be used exclusively.