Sir.—Surgery for a child with hemophilia B can be safely accomplished by maintaining factor IX levels above 20%.1 Although this can be done with plasma prothrombin concentrate, its use has been associated with thrombotic complications.2-5 Fresh-frozen plasma avoids thromboses, but the volumes required are excessive. These potential dangers are magnified in the newborn period, especially in the premature infant.
We report a successful approach to the preoperative and postoperative management of patent ductus arteriosus ligation in an extremely immature infant with documented factor IX deficiency.
Patient Report.—The infant was a 580-g Hispanic male delivered after 24 weeks' gestation complicated only by spontaneous rupture of membranes. The mother was a 23-year-old gravida 7, para 0, aborta 6. Apgar scores were 3, 4, and 7 at 1, 5, and 10 minutes, respectively.
The maternal grandfather has hemophilia B with a factor IX level of 1.8%. He has five