Which solution is used for fluid replacement during dialysis?

• A. 0.45% saline
• B. 0.9% normal saline
• C. 5% dextrose
• D. Lactated Ringer's

Answer: (B)

Fluid replacement during dialysis uses an isotonic solution because it stays in the intravascular space without drawing water into or out of cells. Normal saline (0.9% sodium chloride) matches plasma osmolality, so it expands circulating volume safely and predictably, which is important for maintaining blood pressure and perfusion during dialysis.

The other options have drawbacks. A hypotonic solution would lower plasma osmolality and can cause water to shift into cells, risking cellular edema and instability of intravascular volume. A dextrose solution is hypertonic and can raise blood glucose and cause osmotic shifts that complicate fluid balance. Lactated Ringer’s contains electrolytes, including potassium and calcium, which can disrupt precise electrolyte control during dialysis and are generally not used for routine intravascular fluid replacement in this setting.