HYDROGEN ION [H]+ LOAD AND CALCIUM-PHOSPHATE SOLUBILITY IN IV NUTRITION AND THE PRETERM INFANT (PTI)

Abstract

Significant osteopenia occurs in circa 30% of PTI. Inadequate mineral substrate intake to match intrauterine accretion rates is thought to be a major cause. Calcium (Ca) and Phosphate (iP) intake in IV feeding is restricted by solution solubility to less than half the desired intake. 17 PTI (median wt 1.20kg, gest 28w) were entered into a cross-over study comparing Addiphos (KabiVitrum) and K2 HPO4 as the iP source, while keeping amino acid intake standard. Results: (i) An increase in Ca - iP solubility and increased Ca and iP intake (P<0.001) can be achieved by lowering solution pH using Addiphos instead of K2 HPO4. (ii) Plasma Ca and iP is significantly increased with Addiphos (P<0.01). (iii) To match intrauterine Ca and iP accretion there was a 2x increase in [H]+ load. (iv) With (iii) there was no significant change in blood acid-base parameters, but there was an increase in urine titratable acidity excretion. Conclusion: Intravenous Ca and iP concentration of infusion can be increased by lowering pH of parenteral solution using Addiphos. This increased [H]+ load is well tolerated by PTI.