Water and mineral balance during total parenteral nutrition

The water balance of 10 full-term infants was investigated during postoperative total parenteral nutrition. When only the output of water in faeces, urine and vomit was taken into account the infants gained water (positive balance), 36.4 +/- 4.1 g/kg/day, with the given infusion. The total mean evaporative water loss was calculated to be 26.5 +/- 2.4 g/kg/day, which is slightly higher than that found in healthy newborn infants. When the same amounts of zinc and copper per kg body weight were given to two pre-term and to two full-term newborn infants, lower zinc concentrations were found in the serum of the pre-term infants. Negative balances of zinc were found in the pre-term infants, indicating that pre-term infants need more zinc/kg. Serum copper levels were normal in all infants.