Effect of heparinization of fluids infused through an umbilical artery catheter on catheter patency and frequency of complications. Prevention of umbilical artery catheter clots with heparinized infusates. Effect of adding heparin in very low concentration to the infusate to prolong the patency of umbilical artery catheters. Effect of heparin infusates in umbilical arterial catheters on frequency of thrombotic complications. Efficacy of thromboresistant umbilical artery catheters in reducing aortic thrombosis and related complications. Heparin and the risk of intraventricular hemorrhage in premature infants.
Heparinization of fluids (1 unit/ml) infused through an umbilical artery catheter (UAC) was efficacious in prolonging catheter patency in a double-blind, randomized, controlled clinical study. On the basis of life-table analysis, the half-life of catheter function was seven days in the heparinized group as compared with just over two days in the nonheparinized group (P less than .01). UAC occlusion occurred in 4 of 32 patients in the heparinized and 19 of 30 in the nonheparinized group (chi 2 = 17.6, P less than .01). Blood transfusions, number of arterial blood gases drawn through the UACs, and fluid infusion rates were not related to catheter occlusion. Heparinization of the UAC infusion did not alter the partial thromboplastin time or the incidence of catheter-related thromboembolic phenomena in the extremities. Heparinization of fluids infused through a UAC appears to be useful in the care of critically ill neonates. 49 neonates requiring umbilical artery catheters (UACs) were randomly assigned to receive standard or heparin-containing infusates. 3 of 23 (13%) of the patients receiving heparin had catheters removed because they became functionally occluded compared to 15 of 26 (58%) in the control group (p less than 0.005). 4 of 13 (31%) single injection aortograms obtained in control infants demonstrated thrombi, compared to none of 7 in the heparin group. 1 patient in the heparin group had an aortic clot demonstrated at post-mortum examination. There were neither clinical coagulopathies nor abnormalities of partial thromboplastin time attributable to the administration of heparinized fluids. Heparinization of UAC infusates appears to be a safe method of reducing the risk of catheter occlusion. Heparin effect on large vessel clot risk remains unproven. A randomized controlled study was done to determine whether the addition of heparin, in very low concentration (0.25 U/ml), to fluids administered through an umbilical artery catheter (UAC) would affect the duration of catheter patency. UAC occlusion occurred in 2 of 15 patients in the heparin group and in 11 of 15 patients in the control group (p = 0.001). Using life-table analysis, the functional life span of UAC was estimated. On day 8, 100% of UACs in heparin group and 9% of UACs in control group were patent (p < 0.05). Coagulation profile remained unaltered after addition of heparin compared with that before the start of the therapy. There was no difference in the incidence of subependymal intraventricular hemorrhage between the two groups. It is concluded that heparin in such low concentration is effective in prolonging duration of UAC patency without causing adverse effects. 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. 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. This study was carried out to determine whether the routine use of low-dose heparin in umbilical catheter infusates increases the risk of intraventricular hemorrhage or alters the coagulation profile in premature infants.
                In a randomized, blinded trial, 113 infants born at less than 31 weeks' gestation were assigned to receive, in their umbilical catheter infusate, either 1 unit of heparin per milliliter (n = 55) or no heparin (n = 58). Prothrombin time, activated partial thromboplastin time, fibrinogen concentration, and antithrombin III activity levels were determined at the start and the completion of the study. Cranial ultrasonography was performed during the first week of life.
                There was no difference in the incidence of intraventricular hemorrhage between the heparin and no heparin groups, 35.8% and 31.5%, respectively (p = 0.6). Similarly, no difference was detected in the incidence of severe intraventricular hemorrhage (grades III/IV). Prothrombin time, activated partial thromboplastin time, and fibrinogen levels were not significantly different between the two groups. However, the use of heparin was associated with a lower antithrombin III activity level. Antenatal indomethacin use was associated with a 2.9 increased risk of intraventricular hemorrhage (95% confidence interval, 1.15 to 7.17).
                A low dose of heparin added to umbilical catheter infusates does not increase the incidence or severity of intraventricular hemorrhage or significantly alter the coagulation profile in premature infants.
Heparinization of the fluid infused through an umbilical arterial catheter decreases the likelihood of umbilical arterial catheters occluding. The lowest concentration tested so far (0.25 units/mL) has been shown to be effective. Heparinization of flushes without heparinizing the infusate is ineffective. The frequency of aortic thrombosis has not been shown to be affected; however, the confidence intervals for this effect are very wide. The frequency of intraventricular hemorrhage has not been shown to be affected by heparinization of the infusate, but again the confidence intervals are very wide and even a major increase in the incidence of grade 3 and 4 intraventricular hemorrhage would not have been detected.