During a cholera outbreak, relief teams prepare oral rehydration solution using the currently recommended WHO low-osmolarity formulation. Its total osmolarity is:

• A 311 mOsm/L
• B 280 mOsm/L
• C 245 mOsm/L ✓
• D 200 mOsm/L

Explanation

The reduced-osmolarity WHO ORS contains sodium 75 mmol/L, chloride 65, glucose 75, potassium 20, citrate 10, giving a total osmolarity of 245 mOsm/L. The older standard formulation had an osmolarity of 311 mOsm/L and caused more stool output and occasional hyponatraemia-related issues in practice, which prompted the change. Low-osmolarity ORS reduces stool volume, vomiting and the need for intravenous fluids in cholera and other acute diarrhoeas.

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

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

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