Compare normal saline and lactated Ringer's solution regarding composition and typical use.

• A. Normal saline is isotonic; LR contains lactate and other electrolytes and is a balanced solution; LR is often used for fluid resuscitation but may be avoided in hepatic impairment.
• B. Normal saline is hypotonic; LR is hypertonic; both are used interchangeably in all patients.
• C. Normal saline contains dextrose; LR does not contain electrolytes.
• D. Normal saline is used only for dressing wounds; LR is used only for irrigation.

Answer: (A)

Understanding crystalloids involves comparing composition and how they affect fluid and acid-base balance. Normal saline is 0.9% sodium chloride, which makes it isotonic with plasma and provides sodium and chloride. It’s commonly used for initial fluid resuscitation and basic IV maintenance. But delivering it in large amounts can raise chloride levels and cause hyperchloremic metabolic acidosis, and it may not be ideal for ongoing large-volume resuscitation.

Lactated Ringer's is a balanced crystalloid that includes sodium, chloride, potassium, calcium, and lactate. The lactate acts as a bicarbonate precursor after metabolism in the liver, giving it a mild buffering effect and making LR more like the body's natural electrolyte mix. This is often preferred for fluid resuscitation and perioperative fluid management because it helps maintain acid-base balance better than saline. However, in hepatic impairment, lactate metabolism is reduced, so LR is avoided or used with caution.

So, normal saline is isotonic but can contribute to acidosis with large volumes, while lactated Ringer's is a balanced solution with additional electrolytes and a buffering lactate, used for resuscitation except in patients with liver dysfunction.