India adopted the WHO reduced-osmolarity oral rehydration solution for childhood diarrhoea, including cholera. What is the total osmolarity of this standard ORS formulation?

• A 331 mmol/L
• B 245 mmol/L ✓
• C 200 mmol/L
• D 310 mmol/L

Explanation

The reduced-osmolarity WHO ORS contains sodium 75, chloride 65, potassium 20, citrate 10 and glucose 75 mmol/L, giving a total osmolarity of 245 mmol/L. The earlier full-strength formulation had an osmolarity of 311 mmol/L with sodium 90, and was replaced because the lower solute load reduces stool output, vomiting and the need for unscheduled intravenous fluids. Sodium 90 belongs to the old formula, not the current one.

Reference: Park's Textbook of Preventive and Social Medicine, 27th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

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