OBJECTIVETo evaluate the efficacy and safety of the parenteral administration of various quantities of amino acid in preterm infants.

METHODSPreterm infants (birth weight 1000-2000 g) recruited into the study were randomized into three groups. High amino acid group (HP): 2.4 g/(kg.d) of amino acid IV within 24 hours after birth increasing by increments of 1.2 g/(kg.d) to a maximum of 3.6 g/(kg. d); medium amino acid group (MP): 1.0 g/(kg.d) of amino acid IV 24 hours after birth, increasing by increments of 0.5 g/(kg.d) until a maximum of 3.0 g/(kg.d); and low amino acid group (LP): 0.5 g/(kg.d) of amino acid on D3, increasing by increments of 0.5 g/(kg.d) until a maximum of 3.0 g/(kg.d) as the final dose.

RESULTSTotally 96 preterm infants were recruited: HP 34, MP 32 and LP 30. There were no significant differences in demographic or clinical characteristics among the 3 groups. HP group showed lower postnatal weight loss (43.4 g, 95% CI 74.3, 12.6) and weight loss% (2.84%, 95% CI 4.79%, 0.71%) than LP group. HP group showed shorter length of stay in NICU (5.25 d), days to reach 2000 g (7.03 d) and days to tolerate 100 kcal/(kg.d) enteral nutrition (4.52 d) than LP group. Cost of hospitalization was significantly lower in HP group than in LP group (-6275 RMB, 1 US$=8 RMB) and MP group (-5715 RMB). Mean serum RBP (D4), threonine and tyrosine levels were significantly higher in HP group than in LP group. Serum insulin levels were similar; mean serum glucose level was lower in HP group than in LP group. HP infants had lower incidence of sepsis than LP infants (21.9% vs 40.0%). There were no significant differences in the levels of blood ammonia, acid-base balance (as determined by pH and NaHCO3-), BUN, Cr, AST, and ALT.

CONCLUSIONSIntensive and early administration of intravenous amino acid [2.4 g/(kg.d)] improves preterm infants' growth and the tolerance of enteral feeding. It also reduces the cost of hospitalization, and the incidence of sepsis.