W Wong, TF Fok, CH Lee, KW So, Y Ou, YK Siu, KL Cheung, PC Ng

In the absence of a general consensus among paediatricians, a variety of crystalloid and colloid solutions are being used for partial exchange transfusions (PET) in the treatment of polycythaemia in newborns. These include fresh whole blood, fresh frozen plasma, plasma protein fraction, 5% albumin, isotonic saline, Ringer solution and serum. Fresh whole blood and fresh frozen plasma are no longer recommended because of the risk of transmission of severe infections. The crystalloid solutions, being cheaper and infection-free, are obviously superior to the colloid if their efficacy can be proven.

In a randomized controlled trial that is still ongoing, we compare the use of isotonic saline and 5% albumin in PET in the treatment of polycythaemic newborns. Criteria for PET were as follows: (1) haematocrit (Hct) >= 70% with or without symptoms or (2) Hct >= 65% with symptoms. These patients were randomized into two groups - in group one normal saline was used for the PET and in group two 5% albumin. Our preliminary results show that among the 23 infants so far randomized, PET with either saline (n= 10) or 5% albumin (n= 13) resulted in a significant decline in Hct immediately after PET, and the Hct at 4 and 24 hours post-PET were significantly lower than the pre-PET Hct. The magnitude of fall in Hct and the 4 and 24-hour post-PET Hct did not differ between the saline and albumin groups (Table).

PET with either replacement fluids was not associated with any complication. The serum sodium and potassium concentrations were not significantly affected by the PET in either group. We concluded that isotonic saline solutions can replace colloid solutions in the treatment of polycythaemic neonates. We are at present trying to enroll more infants in order to improve the power of our study.