Chapter 84: Vasospasms and Thromboembolism

I. PROBLEM

An infant with an indwelling umbilical artery catheter develops a vasospasm in 1 leg. The nurse notifies you that another infant with an indwelling umbilical line has no pulses in the lower legs with severely decreased perfusion. Infants during the first month of life are at much higher risk of thrombosis and its complications when compared to any other pediatric age. This is due to many factors: an immature coagulation and fibrinolytic system (hypofibrinolytic state, decreased synthesis and altered function of some coagulation proteins, accelerated clearance of factors, platelet function differences, more active coagulation mechanism), smaller vessel size, and frequent indwelling catheter use (thrombogenic material in catheter, catheter slows blood flow and may damage the vascular endothelium, frequent medications may damage vessel wall). Other risks include maternal, delivery, neonatal, acquired, and inherited prothrombotic abnormalities. Incidences vary depending on the source, type of thrombosis, and screening methods used, but overall incidence of a symptomatic thromboembolic event is 5.1 per 100,000 live births and 2.4 to 6.8 per 1000 neonatal intensive care unit (NICU) admissions, affecting term and preterm male and females equally.

II. IMMEDIATE QUESTIONS

1. Is there a catheter in place? Can the catheter be removed? Catheters involved include central venous catheters, arterial and venous umbilical catheters, and other arterial catheters. The most prevalent risk factor for an arterial or venous thrombosis is an indwelling vascular catheter. It has been stated that “90% of thromboembolic events are catheter related.” Evaluate the need for the catheter. If the catheter can be removed, this is the treatment of choice. Vasospasm is most commonly related to the use of umbilical artery catheters (UACs), but it can also occur in other catheters such as radial artery catheters. Over 90% of venous thromboembolisms in newborns are secondary to central venous lines. Portal venous thrombosis is often associated with the placement of an umbilical venous catheter (UVC). Arterial thromboses are almost always secondary to arterial vascular catheterization of central or peripheral arteries (UAC: renal artery thrombosis, aortic thrombosis). In some cases of thrombosis, the catheter should not be removed so thrombolytic medication can be given into the line. Note: Renal vein thrombosis is the most common type of venous thrombosis not related to a central venous catheter.

2. Was a medication given recently through the catheter? Most medications, if given too rapidly, can cause a vasospasm.

3. How severe is the vasospasm? Deciding on the severity of the vasospasm may dictate treatment choices (see Sections IV.B.1 and IV.B.2).

4. Is there a pulse in the affected extremity? A loss of pulse with a thrombus is a medical emergency.

5. Does the infant have any risk factors for thromboembolism?

   1. Maternal. Advanced maternal age, hypertension, autoimmune disorders, premature rupture of membranes, maternal diabetes, maternal obesity, maternal lupus, preeclampsia, infertility, oligohydramnios, prothrombotic disorder, intrauterine growth restriction (IUGR), chorioamnionitis, family history of thrombosis, antiphospholipid or anticardiolipin antibodies.

   2. Delivery. Instrumentation, fetal heart rate abnormalities, emergency delivery/cesarean section, ...