Metabolic Responses to Early and High Protein Supplementation in a Randomized Trial Evaluating the Prevention of Hyperkalemia in Extremely Low Birth Weight Infants

Objective: To determine whether early and higher intravenous amino acid (EHAA) supplementation decreases hyperkalemia in extremely low birth weight (ELBW) infants (<1000 g). Study design: Infants were enrolled at birth in a randomized, double-masked, prospective fashion and treated for 7 days. The standard group (SAA) infants received intravenous amino acid (AA) starting at 0.5 g · kg^-1 · d^-1 and increased by 0.5 g · kg^-1 every day to a maximum of 3 g · kg^-1 · d^-1. EHAA group infants received 2 g · kg^-1 · d^-1 of AA soon after birth and advanced by 1 g · kg^-1 every day to 4 g · kg^-1 · d^-1. Data analysis was by SPSS 11.5, with statistical significance at α = 0.05 and 90% power to determine a difference in mean K⁺ level of 2. Results: Sixty-two patients, mean gestational age of 26.0 ± 2.0 weeks and birth weight of 775 ± 136 g, were enrolled. Hyperkalemia (K⁺ ≥6.5 mEq/L) occurred in 13% of the studied population; no difference in incidence of hyperkalemia was found between the SAA and EHAA groups (16% vs 10%, respectively, P = .70). Serum blood urea nitrogen was higher in the EHAA group. AA infusion was stopped early in 6 patients for high blood urea nitrogen or elevated ammonia level. Conclusions: During the study period, hyperkalemia decreased significantly and was not affected by EHAA supplementation in the first week of life.