Umbilical artery catheterization in newborns. III. Thrombosis--a study of some predisposing factors

Nurses' guide to early detection of umbilical arterial catheter complications in infants

Umbilical arterial catheters (UAC) are routinely used in the care of critically ill newborns. Complications related to UACs include vascular compromise, hemorrhage, complications related to malposition, severance of the catheter itself, and infection. This article is Part II in a series dedicated to assessing infants with an umbilical catheter. Part I focused on infants with umbilical venous catheters; this article will focus on the physical assessment relevant to infants with an UAC. Complications related to UACs can occur during any phase of treatment: insertion, while indwelling, or after discontinuing the catheter. Review of clinical signs of complications along with clinical photographs, will assist caregivers in promptly recognizing UAC-related complications.

Changes of the coagulation and fibrinolysis system in malignancy: their possible impact on future diagnostic and therapeutic procedures

The interaction between malignant cell growth and the coagulation and fibrinolysis system has been a well known phenomenon for decades. During recent years, this area of research has received new attention. Experimental data suggest a role for the coagulation and fibrinolysis system in tumor development, progression and metastasis. Also, clinical research suggests that targeting the coagulation system or fibrinolysis system might influence the course of malignant disease beneficially. This paper reviews data on various hemostatic and fibrinolytic parameters in malignancy; the possible use of such parameters as risk markers in oncology patients; and possible targets of anti-neoplastic therapies using anticoagulant and/or antifibrinolytic strategies. Current evidence suggests that the tissue factor/factor VIIa pathway mediates the most abundant procoagulant stimulus in malignancy via the increase in thrombin generation. Tissue factor has been suggested to mediate pro-metastatic properties via coagulation-dependent and coagulation-independent pathways; tissue factor has also been implicated in tumor neo-angiogenesis. However, so far no model has been validated that would allow the use of tissue factor in its soluble or insoluble form as a marker for risk stratification in tumor patients. On the other hand, there is now good evidence that parts of the fibrinolytic system, such as urokinase-type plasminogen activator and its receptor ("uPAR"), can be used as strong predictors of outcome in several types of cancer, specifically breast cancer. Observation of various treatment options in patients with thromboembolic disease and cancer as well as attempts to use anticoagulants and/or therapies modulating the fibrinolytic system as anti-neoplastic treatment strategies have yielded exciting results. These data indicate that anticoagulant therapy, and specifically low molecular weight heparin therapy, is likely to have anti-neoplastic effects; and that their use in addition to chemotherapy will probably improve outcome of tumor treatment in certain types of cancer. However, the body of clinical data is still relatively small and the question whether or not we should routinely consider the coagulation and/or fibrinolysis system as therapeutic targets in cancer patients is yet to be answered.

von Willebrand factor-collagen binding activity is increased in newborns and infants

von Willebrand factor (vWF) antigen (vWF:Ag) and vWF-collagen binding activity (vWF:CBA) were measured in plasma by parallel quantitative ELISAs in normal newborns and infants (n = 71). The medians for vWF:Ag (IU/ml) and vWF:CBA (U/ml), respectively, were 1.46 and 1.91 for 2-7 day-old (n = 43), 1.22 and 1.40 for 2-4 week-old (n = 14), 1.22 and 1.15 for 2-6-month-old (n = 14) infants and 0.98 and 1.08 (n = 36) in normal adults. Elevated levels of vWF:Ag, but particularly vWF:CBA were seen for up to 4 weeks of life reaching adult levels between 2 and 6 months of life. The elevated levels of the vWF parameters indicate that caution should be exercised when interpreting laboratory data and diagnosing von Willebrand disease in newborns and young infants and warrant the use of age-specific reference ranges. The efficient haemostasis observed during early neonatal life may in part be due to the increased ability of vWF to interact with collagen.

Management of aortic thrombosis secondary to umbilical artery catheters in neonates

During the past ten years, we have surgically managed seven neonates who developed total occlusion of the distal aorta due to umbilical artery catheters. All patients experienced symptoms of congestive heart failure. Five patients presented with severe hypertension, and all of these had aortorenal involvement: three infants had aortorenal thrombosis and two infants had infrarenal aortoiliac thrombosis with suprarenal extension of thrombus. Two infants had aortoiliac thrombosis with clot confined to the infrarenal aorta. Aortic thrombosis imposes an additional severe hemodynamic insult in these already seriously ill infants. Survival in this group of patients depends upon prompt recognition of this problem, effective surgical correction, and careful perioperative management. Our experience suggests that this diagnosis should be entertained in the infant presenting suddenly with congestive heart failure, hypertension, or lower limb ischemia after umbilical artery catheterization. The diagnosis is preferably confirmed by real-time ultrasound and/or radionuclide flow scan, although aortography may sometimes be necessary. Surgical management includes early transabdominal aortotomy with thrombectomy. Prompt thrombectomy resulted in the survival of six patients. One infant died in acute renal failure. Renal function and leg perfusion is satisfactory in the remaining patients, although one child required later operative correction of renovascular hypertension. Two additional patients needed prolonged postoperative antihypertensive therapy for 14 to 34 months before this problem resolved. Long-term follow-up is necessary for managing renovascular hypertension and monitoring lower extremity perfusion.

Congestive heart failure and absent femoral pulses in newborns without coarctation of the aorta

Two infants with thrombosis of the abdominal aorta are discussed. In each case the presentation was indistinguishable from that in coarctation of the aorta, with heart failure and absent femoral pulses. Surgery in one infant successfully relieved the obstruction. The diagnosis may not be suspected from the history. Aggressive management is indicated.

Newborn factor VIII complex: elevated activities in term infants and alterations in electrophoretic mobility related to illness and activated coagulation

The factor VIII coagulant activity (FVIII:C), factor VIII related antigen (FVIII:RAG), and factor VIII ristocetin cofactor activity (FVIII:RCF) was determined in the cord blood samples of 30 healthy term newborns. Sodium citrate anticoagulant, cold, and a proteolytic inhibitor were used in sample processing. All three factor VIII activities were elevated in infants compared to adults; additionally, FVIII:RAG was significantly higher in vaginally compared with caesarean section delivered infants. Crossed immunoelectrophoresis of the term infant plasma showed a consistently normal factor VIII mobility. An additional group of 22 sick premature and term infants had determinations of factor VIII antigen and crossed immunoelectrophoresis. The FVIII:RAG of sick infants was approximately twice that of the well term infants. Infants with severe lung disease, asphyxia, thrombosis and sepsis had normal electrophoretic mobility despite marked elevations in FVIII:RAG. Abnormal, symmetrical, more anodal migrations were seen only in a group of severely ill newborns with dissiminated intravascular coagulation (DIC) or signs of activated fibrinolysis. These results suggest that the elevated FVIII activities seen in well infants and most sick newborns are the result of increased release of a normal form of the FVIII molecule. Those elevations seen in sick newborns with DIC result from increased release and the production of an altered, faster moving FVIII molecule.

Renal blood flow in high and low positions of aortal catheter in rabbits

The effect of aortal catheterization on renal blood flow (RBF) was evaluated in seven rabbits weighing 2500 to 3500 g. RBF was measured 21 times from 13 kidneys during aortal catheterization with an isotope (133 Xe) technique. The catheter was positioned in the aorta of each rabbit both above and below the origins of the renal arteries. The results of these two measurements were compared. Two phases of RBF, a fast first phase and a slow second phase, were determined. The fast phase of RBF was 5.3 ml/g/min, when it was in the high position. The results of the slow phase were identical, 0.16 ml/g/min, in both positions. No significant statistical difference could be found according to the phase of the catheter (paired t-test). These results in rabbits suggest that the aortal catheter does not cause any immediate decrease in RBF. This finding has clinical importance in aortal catheterization in neonates to obtain arterial blood samples. When considering the position of the aortal catheter in neonates factors other than RBF should be taken into account.

Umbilical artery catheterization in newborns. V. A clinical follow-up study

The long-term effects of umbilical artery catheterization were studied in forty-nine children. At the age of about 18 months their gross motor and neurological development, peripheral circulation, and growth of the legs were investigated. The infants with catheter-related thrombo-embolism in the legs diagnosed in the neonatal period with the aid of angiography and investigated by plethysmography were re-examined once or more during the first year of life by strain-guage plethysmography. One child who showed total occlusion of the iliac artery as newborn, had a difference in calf circumference at the 18-month examination of 1.5 cm, the only finding in this study related to catheter-associated thrombosis. In infants with neonatal thrombo-embolism in the legs the initial crural difference in systolic blood pressure diminished slowly, and at 12 months a blood-pressure difference of more than 10 mmHg remained in only one infant.