Abstract

1. The renal clearances of mannitol and sodium para-aminohippurate were determined before and during anesthesia. Ether was administered to eight human subjects and cyclopropane to seven.

2. All studies were conducted on patients in good condition with normal renal function as inferred from the usual clinical criteria. All observations were completed before any surgical procedures were started.

3. In seven of the eight patients who received ether, and in all who received cyclopropane, the average glomerular filtration rate and effective renal plasma flow fell during anesthesia. The average filtration fraction rose in each patient except in one, who also showed no significant changes in mannitol or para-aminohippurate clearances. Average urine flow fell in both groups, accompanied by a rise in the average U/P ratio. Individual variations in all of these measurements were observed.

4. The changes in kidney function observed during ether and cyclopropane anesthesia were qualitatively similar; quantitatively, they were greater with cyclopropane, and somewhat less subject to individual variation. Thus, average glomerular filtration rate fell 21 pen cent with ether, and 31 per cent with cyclocpropane; average effective renal plasma flow fell 39 per cent with ether and 52 per cent with cyclopropane; average filtration fraction rose 25 per cent with ether and 35 per cent with cyclopropane.

5. Possible reasons for the variation of our data from that of previous workers are presented. Certain physiologic and therapeutic implications of these data are suggested.