Type 4: Osmolarity of IV solutions (D5W, D5NS, D5½NS)

5. mEq and mOsmol 5.2) mOsmol 5.2.1) mOsmol - General

5.2.1.1) mOsmol - General Hard 1


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Calculate the total milliosmoles of 50 mL of dextrose 5% solution in water (D5W).


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lb equals 13.89 mOsmol kg

    Dextrose 5% means 5g of dextrose is present in 100 mL. The volume of the solution is 50 mL.
    Since it does not dissociate in the solution, for dextrose, we can write the 'golden formula' as:
    `1\quad mmol=[180]` mg = `[1]` mOsmol.

    Using dimensional analysis:

    `(5 \quad g)/(100 \quad mL) × (1000\quad mg)/(1\quad g) × (1\quad mOsmol)/(180\quad mg) × 50 \quad mL`
    `= 13.89` mOsmol. Ans.