86. REDUCTION IN NEONATAL HYFHWENYLAIMMAFKIA WITH A LOW PHENYL-ALANINE AMINO ACTD SOURCE

Abstract

We have recently drawn attention to the worrying incidence of hyperphenylalaninaemia in parenterally fed neonates (1), and have therefore compared Vamin 9 Glucose (KabiVitrum; 5.5 g/1 phenylalanine) with Vaminolac (KabiVitrum; 2.7 g/1 phenylalanine), a modified amino acid solution based upon the composition of human breast milk. Neonatal surgical patients requiring total parenteral nutrition were randomly allocated to receive either Vamin or Vaminolac as the amino acid source. 13 patients (A gastroschisis, 4 small bowel atresia, 3 necrotising enterocolitis, 2 tracheo-oesophageal fistula) were given Vamin and 6 (4 NEC, 1 gastroschisis, 1 jejunal volvulus) received Vaminolac. Amino acid intake was stabilised at 2.5g/kg/ day for a minimum of 3 days prior to plasma amino acid analysis, performed twice weekly for one week, then at weekly intervals. The median plasma phenylalanine concentration in the Vamin group was 200Umol/l (range 49-983umol/l, n=32) compared with only 68umol/l (range 47-154umol/l, n=13; p < 0.00003) even though patients receiving Vamin were of significantly greater post-conceptual age at the time of sampling (median 38 weeks, range 31-53 weeks) than Vaminolac patients (median 38 weeks, range 31-41 weeks; p< 0.00003). No patients had grossly elevated plasma tyrosine concentrations or evidence of liver dysfunction. Three of the neonates given Vamin were found to have plasma phenylalanine concentrations above the commonly accepted neuro-toxic level of 600umol/l. The use of Vaminolac compared with Vamin 9 Glucose is therefore associated with a significant reduction in potentially toxic plasma phenylalanine concentrations. (1) Puntis JWL et al., Lancet 2:1105-1106 (1986).