Which IV fluids most closely resemble jejunal electrolyte content?

Which IV fluids most closely resemble jejunal electrolyte content?

• A. Normal saline
• B. 1/2 normal saline
• C. D5 0.45% NaCl
• D. Lactated ringers

Answer: (D)

The key idea is matching IV fluid composition to the electrolyte content of jejunal secretions to replace losses without upsetting acid–base balance. Jejunal fluid is roughly isotonic with extracellular fluid and contains sodium and chloride along with bicarbonate, plus small amounts of potassium and calcium. An IV fluid that closely mirrors this pattern is lactated Ringer’s solution. It provides sodium, chloride, potassium, and calcium in physiologic amounts and includes a lactate component that the body rapidly converts to bicarbonate, helping buffer any acidosis from GI losses. This combination makes it the closest match to jejunal electrolyte content among common IV fluids. Normal saline has a high chloride load and no potassium or calcium, which can worsen acid–base balance when given in volume. Half-normal saline is hypotonic and lacks several electrolytes and bicarbonate buffering. A dextrose-containing solution with 0.45% saline adds free water and glucose but does not adequately replace the electrolyte content of jejunal secretions.

The key idea is matching IV fluid composition to the electrolyte content of jejunal secretions to replace losses without upsetting acid–base balance. Jejunal fluid is roughly isotonic with extracellular fluid and contains sodium and chloride along with bicarbonate, plus small amounts of potassium and calcium. An IV fluid that closely mirrors this pattern is lactated Ringer’s solution. It provides sodium, chloride, potassium, and calcium in physiologic amounts and includes a lactate component that the body rapidly converts to bicarbonate, helping buffer any acidosis from GI losses. This combination makes it the closest match to jejunal electrolyte content among common IV fluids.

Normal saline has a high chloride load and no potassium or calcium, which can worsen acid–base balance when given in volume. Half-normal saline is hypotonic and lacks several electrolytes and bicarbonate buffering. A dextrose-containing solution with 0.45% saline adds free water and glucose but does not adequately replace the electrolyte content of jejunal secretions.