Question

A patient is ordered to receive chloride supplementation by intravenous infusion of a sodium chloride solution [Na CI, MW-58.44 g/mol). The patient is ordered to receive 0.7 mEq of CI - ions per hour. A 750 mL intravenous bag is prepared that contains 17 mL of a 14.6% solution of sodium chloride. What should be the infusion rate (in units of mL/min) necessary to produce the ordered dose of 0.7 mEq/hr of chloride? (Note: Consider the total solution volume to be 750 mL. Also assume the sodium chloride salt completely disassociates in solution. Please do not assume the specifics of this question are exactly clinically relevant due to the variability in this question.)

Answer 1

14.6% NaCl means 14.6 gram of NaCl in 100 ml of the solution .

So amount of NaCl in 17 ml = 14.6 * 17 /100= 2.48 gram = 2480 mg

So number of moles of NaCl= 2480/58.5 = 42.4 millimoles

So number of equivalents of Cl- = 42.4 new

So 42.4 mEq of Cl- present in 750 ml of solution.

So 0.7 mEq present in 750/42.4 * 0.7 = 12.38 ml

Infusion rate per minute = 12.38/60 = 0.21 ml/minute.

So the infusion rate should be 0.21 ml/minute.