Intensive plasma exchange in the management of severe Rh disease

Fourteen high-risk cases of Rh alloimmunized women were treated by intensive plasma exchange on the cell separator throughout their pregnancies. The mean volume of plasma exchanged per week was 3.21 with a total volume of 10-123 1. The replacement fluid was mainly plasma protein fraction (PPF) supplemented with fresh frozen plasma (FFP). The mean duration of treatment was 131/2 weeks, ranging from 2 to 22 weeks, commencing at 12-30 weeks gestation. The complications encountered and the selection of the optimal time for delivery are discussed. The expected stillbirth rate in this series as determined by their past obstetric histories and anit-D levels was 62%. Intrauterine transfusion was given to only two of the infants and both were later stillborn. It was possible to reduce and maintain a lower level of anti-D in the serum of most of the patients and a successful outcome was achieved in nine of the 12 cases included for analysis (75%). Plasma exchange commenced early in pregnancy is recommended as a non-hazardous form of treatment in the management of severe Rh haemolytic disease. However, if the mean level of anit-D cannot be maintained at less than 35 iu/ml then the outcome is more likely to be fatal. Amniocentesis should be delayed where possible until 28 weeks gestation and intrauterine transfusion reserved for those cases where the anti-D level becomes uncontrollably high and the fetal death is imminent.