A child suffering from acute diarrhoea is brought to the casualty and is diagnosed as having severe dehydration with pH of 7.23. Serum Na– 125, Serum K– 3, HCO3– 16. The best I.V. fluid of choice is –
**Core Concept**
The child in this scenario is suffering from severe dehydration, which is a life-threatening condition that requires prompt and accurate fluid management. The presence of metabolic acidosis, indicated by a low pH and decreased bicarbonate levels, necessitates the use of a specific type of intravenous (I.V.) fluid that can help correct the acid-base imbalance.
**Why the Correct Answer is Right**
The child requires a fluid that is rich in sodium and chloride to correct the severe dehydration, but also needs a buffer to help correct the metabolic acidosis. The correct choice is a fluid that contains bicarbonate, which will help increase the serum bicarbonate levels and correct the acid-base imbalance. The fluid should also contain some potassium to help replace the lost potassium ions.
**Why Each Wrong Option is Incorrect**
* **Option A:** This fluid is hypotonic and contains very little sodium, which is not suitable for severe dehydration. It also lacks bicarbonate, making it a poor choice for correcting metabolic acidosis.
* **Option B:** This fluid is also hypotonic and contains some potassium, but it lacks the necessary bicarbonate to correct the metabolic acidosis. It may even worsen the condition if used alone.
* **Option C:** This fluid contains some sodium and chloride, but it lacks bicarbonate and may even contain some lactate, which could worsen the metabolic acidosis.
**Clinical Pearl / High-Yield Fact**
In cases of severe dehydration with metabolic acidosis, it's essential to use a fluid that contains bicarbonate to help correct the acid-base imbalance. The choice of fluid should be based on the severity of dehydration and the presence of other electrolyte imbalances.
**Correct Answer:**
* **Normal Saline with 4.3% Sodium Bicarbonate (Hartmann's Solution)**: This fluid contains 130 mEq/L of sodium, 109 mEq/L of chloride, and 28 mEq/L of bicarbonate, making it an ideal choice for correcting severe dehydration and metabolic acidosis in this child.