79: Vasospasms and Thromboembolism

I. PROBLEM

An infant with an indwelling umbilical artery catheter develops a vasospasm in one 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 are at a high risk for thromboembolism because of their immature hemostatic system and smaller vessel size, and the fact that they require frequent catheter use. The majority of neonatal thromboembolisms are iatrogenic from umbilical artery or venous catheters, indwelling central catheters, and peripheral arterial lines.

II. IMMEDIATE QUESTIONS

1. Can the catheter be removed? 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 80% of venous thromboembolisms in newborns are secondary to central venous lines. Arterial thrombosis is less common than venous thrombosis. The incidence of UAC-related thrombosis is 14–35% by ultrasound, and up to 64% by angiography. In some cases of thrombosis, the catheter should not be removed so thrombolytic medication can be given through it.

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

3. How severe is the vasospasm? Deciding on the severity of the vasospasm may dictate treatment choices (see Section IV.B.1 and 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. Autoimmune disorders, premature rupture of membranes (PROM), diabetes, preeclampsia, infertility, oligohydramnios, prothrombotic disorder, intrauterine growth restriction (IUGR), chorioamnionitis, family history of thrombosis, antiphospholipid or anticardiolipin antibodies.

   2. Delivery. Instrumentation, fetal heart rate (FHR) abnormalities, emergency cesarean section, traumatic delivery.

   3. Neonate. Central arterial catheters (most common risk factor for arterial thromboembolism), central venous catheters (one of the most common risk factors for venous thromboembolism), some congenital heart diseases, birth asphyxia, sepsis, small for gestational age (SGA), respiratory distress syndrome (RDS), polycythemia, necrotizing enterocolitis (NEC), pulmonary hypertension, dehydration, surgery, extracorporeal membrane oxygenation/extracorporeal life support (ECMO/ECLS), congenital renal vein defects, congenital nephrotic or nephritic syndrome, prematurity, hypotension, disseminated intravascular coagulation (DIC), impaired liver function, fluctuations in cardiac output, low cardiac output, prothrombotic disorders.

   4. Inherited factors. Protein C, protein S deficiency; factor V Leiden mutation; antithrombin deficiency; prothrombin gene G20210A mutation; elevated lipoprotein a levels; and others.

III. DIFFERENTIAL DIAGNOSIS

1. Vasospasm. A muscular contraction (spasm) of an arterial vessel, manifested by acute color change (white or blue) in the perfused extremity (upper or lower extremity, sometimes only on the toes or fingers). Occasionally, the color change extends to the buttocks and the abdomen. The change in color may be transient or persistent. It may be caused by prior injection of medication or a manifestation of thromboembolism/thromboembolic phenomenon. Arterial blood sampling can also be a ...