CB is a patient on the medical floor. Earlier today D5 1/2NS + 40 mEq KCl was ordered to run at 75 mL/hr. Unfortunately, an error was made and her 1 liter bag has been running at only 45 mL/hr for the past 4 hours. How many extra mEq of KCl will CB need to receive now to equal what she would have gotten if the drip had been hanging at the correct rate for the past 4 hours?

The total required amount CB should have been receiving for the past 4 hours should be:

Required quantity = (75 mL / hr) * 4 hr

Required quantity = 300 mL

The actual quantity CB received however is only:

Actual quantity = (45 mL / hr) * 4 hr

Actual quantity = 180 mL

Therefore the deficit is:

Deficit quantity = 300 mL - 180 mL

Deficit quantity = 120 mL

Since in a 1 liter (1000 mL) bag there is 40 mEq of KCl, therefore the needed extra mEq of KCl that CB has to receive now is:

Additional KCl = 120 mL * (40 mEq / 1000 mL)

Additional KCl = 4.8 mEq