Rapid Water and Slow Sodium Excretion of Acetated Ringer’s Solution Dehydrates Cells

UNLABELLED: Acetated Ringer's solution is a slightly hypotonic infusion fluid (osmolality 270 mosmol/kg) that has inspired the belief that the fluid causes a shift of water volume to the intracellular space. We assessed the role of the kidney in modifying this volume shift by infusing 25 mL/kg of Ringer's acetate solution (mean, 1565 mL) over a time period of 15, 30, 45, and 80 min on different occasions in 5 healthy female volunteers. Regardless of the rate of administration, the excreted urine contained only half as much sodium (mean, 67 mmol/L) as the infused fluid. As there was only a slight increase of 0.9 mmol/L in the serum sodium level, mass balance calculations indicated that 274 mL of water had shifted from the intracellular to the extracellular space 30 min after the infusions ended (P < 0.001). This fluid shift was also maintained over the subsequent 90 min. In conclusion, infusion of Ringer's acetate solution does not promote cellular swelling as a result of the excretion of urine that is low in sodium. A slight dehydration of fluid from the intracellular space still persisted when our measurements ended 2 h after completing the infusion. IMPLICATIONS: The kidney promotes slight cellular dehydration after infusion of Ringer's acetate solution by rapid excretion of water, whereas natriuresis occurs more slowly. In volunteers, this translocation amounted to 18% of the infused fluid volume and persisted for at least 2 h.