Clinical History:

A two-day old term infant was transferred from a local hospital to newborn intenstive care unit (NBICU) in respiratory distress. On arrival the neonate had ecchymoses over the trunk and legs. Coagulation studies included prothrombin time (PT) and partial thromboplastin time (PTT) each >100 seconds, platelet count 170,000/microliter, and fibrinogen 0 mg/dl. D-dimer levels were not elevated.

Questions:

1. What additional coagulation test should be ordered immediately?

   Testing with correction results in both PT and PTT >100 seconds. These results are consistent with heparin either in a line, or the child, but fibrinogen levels should be measurable.

Further History:

A pathologist was contacted for help in interpreting the results above. Unfamiliar with the reagents used to obtain the current values, he requests a new sample and has the same tests run at UUMC. Results include: PT and PTT each >150 seconds, platelet count 134,000/microliter, fibrinogen 202 mg/dl, and D-dimers were not elevated.

1. Can you explain the difference in fibrinogen levels between the labs?

   The first lab has fibrinogen levels extrapolated from the PT curve. The second lab uses a direct determination of fibrinogen, and heparin only mildly affects the assay.

Further History:

The pathologist was now convinced the infant had been given an overdose of heparin. The nursing staff in the NBICU were surprised when given this information, stating "this child has not even been in the same room with a bottle of heparin."

1. What additional test can be run to convince the staff of the problem?

   A heparin assay = 4.8 U/ml with therapeutic values being .2-.4 U/ml.

2. Fresh frozen plasma (FFP) was ordered for the infant. Will FFP help?

   FFP will not correct the coagulopathy since the infused plasma will only be contaminated with circulating heparin.

3. What should be given to reverse a heparin overdose?

   Protamine sulfate is needed to reverse the heparin.