## a) Dilution and rate of administration

*A 55 year old (62kg) is prescribed one dose of 40 mEq KCl to be administered to correct his hypokalemia. Your pharmacy stocks 10 ml vials of KCl 2mEq/mL. The manufacturer recommends the maximum concentration for administration is 10mEq/100ml and the max rate of administration is 0.5 mEq/kg/hr*

*i) How much diluent would you need to prepare the patient’s dose? (1 mark)*

Pharmacy stock: 10 ml vials of 2 mEq/ml KCl => **20 mEq/10ml**

Patient requires 40 mEq => 2 vials = **40 mEq/20ml**

Max concentration allowed is 10 mEq/100ml => **40 mEq/400ml**

**380ml diluent** is required to convert 40 mEq/20 ml to 40 mEq/400ml.

*ii) From the solution you prepared for this patient, what specific rate of administration would you inform the nurse to give the medication? (2 mark)*

Max administration rate is 0.5 mEq/kg/hr

Patient weighs 62 kg

0.5 x 62 = 31 mEq/hr

You need to calculate how many mls of 40 mEq/400ml will give you 31 mEq.

400ml x (31/40) = 310 ml

Max rate of administration 310ml/hour (or 5.17 ml per min, or round down to 5 ml per min if the machine is not able to be that accurate).

*iii) How long would you anticipate the infusion time to be? (1 mark)*

Infusion rate is 310 ml for one hour. After one hour 90 ml of the 400 mEq/400ml solution will be left.

90/310 = 0.3 hr

in total **1.3 hours. **