Normal renal function in the first two days of life.

Our knowledge about renal function in the first two days of human life is meagre. Most of it is due to Thomson (1944, 1947, 1949), Smith, Yudkin, Young, Minkowski and Cushman (1949) and Hansen and Smith (1953). Dean and McCance (1947) measured the inulin, diodone and creatinine clearances of four children aged 2 days, and other investigators have included one or two children under 3 days old in a series which they were studying for one or more aspects of renal function (Dean and McCance, 1948; Rubin, Bruck and Rapoport, 1949; Vesterdal and Tudvad, 1949) but, except in the case of Ames' (1953) work on the excretion of water, there have never been enough of these children to make much of the findings, and our ideas about the function of the baby's kidney are almost entirely based upon studies which have been made on older age groups (Bamett, 1940; McCance and Young, 1941; Gordon, Harrison and McNamara, 1942; Barnett, Hare, McNamara and Hare, 1948; Dean and McCance, 1949; McCrory, Forman, McNamara and Barnett, 1952). Thomson (1944) gave average figures and the individual scatter for the volumes of the urines of newborn infants, their specific gravities and pH, the concentration of chloride (Cl) and urea, and later (1949) added his findings for the urea clearances. He also (1947) studied two children with 'dehydration fever'. He made no comparisons with adults. In studying renal function, particularly clearances, it is usual to give enough fluid either by mouth or vein to promote a large diuresis. This facilitates the collection of specimens, but it would be an unphysiological thing to do to a baby less than 48 hours old who at that time normally passes through a period of undernutrition and dehydration. It would have destroyed one of the main objects of this investigation, moreover, which was to try to piece together some of the events which normally take place during those two days. The babies were investigated, therefore, under standardized but almost normal conditions and compared with adults who had been subjected to what we know is a similar degree of starvation and hydropenia.