CONCENTRATION OF URINE SOLUTES BY YOUNG INFANTS

Abstract

The water exchange of five infants, one to two months old, is described during the water restriction imposed by feeding food mixtures of undiluted evaporated milk. It is shown that the urine solutes can be concentrated to the level of 1.2 osM/l. The high order of the concentrating ability by the kidneys of these young patients means that, in healthy infants one month old or older, over half of the water provided by the infant's usual food can be conserved to cover abnormal losses by other routes of water removal. A chart is given for the estimation of the renal water requirement for infants at any given concentration of urine solutes on a variety of intakes.