The Effect of Early Protein Supplementation on Prevention of Hyperkalemia in Extremely Low Birth Weight Infants

Randomized double blind prospective clinical trial. All infants admitted to University Hospital neonatal intensive care unit with birth weight of < 1000 grams, mmore than 24 weeks gestation and with no congenital anomalies will be enrolled in the study. This will include inborn infants and those that are transported from outlying hospitals and admitted at <12 hours of life. After informed consent, infants will be randomized to receive either standard of care nutritional management or nutritional management per study protocol with the addition of protein supplementation. Randomization will take place in the pharmacy.

Control Group: Infants enrolled in the control group will be started on intravenous fluids (IVF) on admission to the NICU with 5% Dextrose and 1500 mg calcium gluconate per 500 cc for a total fluid intake of either 120 or 150 cc/kg/day. The attending neonatologist in accordance with the infant's gestational age and maturity will make the decision regarding total fluid intake. The control group will be started at 0.5 gram/kg/d of protein ( Amynosin PF) on DOL 1 and increase by 0.5 gram/kg/day every day to a maximum of 3 grams/kg/day.

Study group: The study group will receive the same total fluid intake (120 cc/kg/day or 150 cc/kg/day) and 5% dextrose infusion with calcium gluconate and the addition of 2 grams/kg/day of protein (Aminosyn PF). The study group will receive 2 grams/kg/day of protein for 24 hours to 36 hours and will increase by 1 gram/kg/day up to a maximum of 4 grams/kg/day.

In both groups, caloric intake will start at 29-34 kcal/kg day (i.e., approximately 20-25 calories per kilogram from glucose and 9 calories per kilogram from lipids). Caloric intake will be progressively increased depending on the infant's tolerance to glucose. Protein to glucose ratio in the control group will be 250-312 and nitrogen balance ratio (including all calories) will be approximately 362-425. In the study group, protein to glucose ratio will be 64-80 and nitrogen balance ratio (including all calories) will be 93-109. The control group corresponds to the current standard of care. The study group nitrogen balance is within the limits of recent studies which show that a nitrogen balance ratio of 46-78 is appropriate for ELBW infants.

Glucose infusion rate (GIR) will be increased by attending neonatologist depending on infant's glucose tolerance. Usually GIR is started at 6 mg/kg/min and increased by 1 milligram per kilo per minute every 24 hrs. in ELBW infants. For fluctuations in glucose, adjustments in glucose infusion rate (GIR) will be via piggyback dextrose to the IVF if necessary.