Question:medium
Which of the following, if given in large volumes, can lead to hyperchloremic metabolic acidosis?
Which of the following, if given in large volumes, can lead to hyperchloremic metabolic acidosis?
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Large-volume normal saline can cause hyperchloremic metabolic acidosis due to excess chloride load.
Updated On: May 14, 2026
- Dextrose in NS (DNS)
- Normal saline (NS)
- 5% dextrose in water
- Ringer lactate
Show Solution
The Correct Option is B
Solution and Explanation
Step 1: Understanding the Question:
This question tests the physiological impact of intravenous fluids on the body’s acid-base balance, specifically focusing on the effects of chloride-rich solutions.
Step 2: Detailed Explanation:
Normal Saline (0.9% NaCl) Composition: Although called "normal," 0.9% saline contains 154 mEq/L of both Sodium (\(Na^+\)) and Chloride (\(Cl^-\)). This chloride concentration is significantly higher than the normal plasma level (approx. 98–107 mEq/L).
Mechanism of Acidosis: When large volumes of NS are infused, the plasma chloride concentration rises significantly (Hyperchloremia). According to the Stewart physical-chemical approach, an increase in chloride relative to sodium decreases the Strong Ion Difference (SID).
Bicarbonate Displacement: A rise in chloride leads to a reciprocal drop in bicarbonate (\(HCO_3^-\)) to maintain electrical neutrality in the plasma. This results in a metabolic acidosis with a normal anion gap.
Alternative Fluids: Ringer’s Lactate (RL) is a "balanced" crystalloid. It has a lower chloride concentration (approx. 109 mEq/L) and contains lactate, which the liver metabolizes into bicarbonate, helping to maintain a physiological pH.
Complications: Hyperchloremic acidosis can lead to decreased renal blood flow and increased risk of acute kidney injury in critically ill patients, which is why balanced fluids are often preferred for massive resuscitation.
Step 3: Final Answer:
Large-volume resuscitation with Normal Saline is the most common cause of iatrogenic hyperchloremic metabolic acidosis.
This question tests the physiological impact of intravenous fluids on the body’s acid-base balance, specifically focusing on the effects of chloride-rich solutions.
Step 2: Detailed Explanation:
Normal Saline (0.9% NaCl) Composition: Although called "normal," 0.9% saline contains 154 mEq/L of both Sodium (\(Na^+\)) and Chloride (\(Cl^-\)). This chloride concentration is significantly higher than the normal plasma level (approx. 98–107 mEq/L).
Mechanism of Acidosis: When large volumes of NS are infused, the plasma chloride concentration rises significantly (Hyperchloremia). According to the Stewart physical-chemical approach, an increase in chloride relative to sodium decreases the Strong Ion Difference (SID).
Bicarbonate Displacement: A rise in chloride leads to a reciprocal drop in bicarbonate (\(HCO_3^-\)) to maintain electrical neutrality in the plasma. This results in a metabolic acidosis with a normal anion gap.
Alternative Fluids: Ringer’s Lactate (RL) is a "balanced" crystalloid. It has a lower chloride concentration (approx. 109 mEq/L) and contains lactate, which the liver metabolizes into bicarbonate, helping to maintain a physiological pH.
Complications: Hyperchloremic acidosis can lead to decreased renal blood flow and increased risk of acute kidney injury in critically ill patients, which is why balanced fluids are often preferred for massive resuscitation.
Step 3: Final Answer:
Large-volume resuscitation with Normal Saline is the most common cause of iatrogenic hyperchloremic metabolic acidosis.
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