What are the fluid replacement principles for renal failure?

For patients with renal failure, the principle of fluid replacement is "output-based intake," meaning that fluid input should be carefully controlled and less is better than more. Specifically, daily fluid intake is calculated as follows: total fluid intake = insensible water loss + sensible water loss – endogenous water production. The details are as follows:

Renal failure usually results from chronic kidney disease that progressively leads to partial or complete loss of kidney function. Renal failure is classified into acute renal failure and chronic renal failure. Acute renal failure develops rapidly, often due to trauma or burns causing insufficient blood supply to the kidneys or urinary tract obstruction, resulting in kidney damage. Chronic renal failure refers to a gradual decline in kidney function caused by long-standing kidney diseases, leading to symptoms such as oliguria (reduced urine output), uremia, and electrolyte imbalances. When patients with renal failure cannot take food orally, fluid replacement can be used to maintain necessary nutrition and stabilize the internal environment. In cases where patients produce little or no urine, the guiding principle for fluid replacement is "output-based intake" and "less is safer."

A rapid drop in serum sodium levels indicates excessive fluid administration, whereas insufficient fluid may lead to dehydration. Both overhydration and underhydration can worsen renal failure. Therefore, during fluid replacement therapy, it is essential to closely monitor the patient's serum sodium levels and central venous pressure.