121 Optimal Potassium Intake for Preterm Infants on Parenteral Nutrition

Abstract

Background and aims: Current guidelines for preterm parenteral nutrition aim to approximate normal foetal growth and avoid postnatal catabolism by achieving an earlier and higher intake of amino acids (AA) and calories (early aggressive parenteral nutrition, EAPN). Few investigations have explored whether electrolytes and water homeostasis could be modified by EAPN, but none have assessed electrolytes needs on EAPN. We performed a prospective observational trial to estimate potassium needs in relation to nutritional approach. Methods: During 14 months all preemies (≤32 weeks) receiving PN in central or peripheral venous line were eligible. During the first week, we performed daily determination of plasma and urine electrolytes (8-hour collection), we recorded intakes, body weight and calculated potassium balance. For analysis infants were divided into 3 groups: low protein (LP) 2g/kg/day. Results: 154 infants were entered. In the HP group kaliemia and kaliuria were significantly lower and non-oliguric hyperkaliemia was prevented. Potassium balance differed among groups: LP -3.6 mmol/kg/wk, MP -0.3 mmol/kg/wk and HP +2.6 mmol/kg/wk (p< 0.001). AA intake was the main independent factor influencing potassium balance, followed by caloric intake and day of life. Discussion: Potassium balance and homeostasis are influenced by cellular integrity and function. AA intake is the main determinant for avoiding catabolism after birth. We showed that early AA intake have a strong influence on potassium balance. Our data allow us to calculate the optimal potassium requirements, in relation to AA and caloric intakes and day of life.