Abstract
Interest in the renal function of newborn infants has been aroused by recent studies which indicate that the glomerular filtration rate is relatively low during the newborn period. The application of a method devised by one of us 1 to 7 apparently normal full-term infants ranging in age from 4 to 9 days suggested glomerular filtration rates between 20 and 40% of the average normal adult values. McCance and Young 2 have since published an extensive study of renal function of newborn infants, in which are included observations on inulin clearances in 3 infants, aged 6 to 13 days, with meningoceles. Urine collections were made by means of catheterization, and the determined inulin clearances were of the order of 43% of the average adult value. These workers pointed out that the inulin clearances varied considerably with the minute urine volumes. In addition, they observed corresponding changes in urea clearances. Gordon, Harrison, and McNamara, 3 determining urea clearances in premature and full-term infants ranging in age from 7 to 70 days, also obtained values considerably below the normal adult levels. They did not find increases in the urea clearances when the flow of urine, initially 0.05 to 0.20 cc per minute or 0.4 to 1.0 cc per square meter per minute, increased by 25 to 100%.
The observations reported here were made on a 24-hour-old infant, weighing 2100 g, who was admitted to the St. Louis Children's Hospital on July 18, 1941, because of an extrophy of the bladder. The 2 ureteral orifices were visible and readily accessible. Ureteral catheters were inserted easily and a steady flow of urine was obtained. Blockage necessitating irrigation of the catheters was not encountered during the period of the studies to be described and it was felt that accurate collections were made with a minimum of manipulation.
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