Worked example

Weight-based IV infusion - practice problem 5

A patient weighing 65 kg has propofol 1000 mg in 100 mL. The prescriber orders 5 mcg/kg/min.

Weight65 kg

Ordered rate5 mcg/kg/min

Bag1000 mg in 100 mL

What pump rate (mL/hr) delivers this order?

Answer: 2 mL/hr

Step-by-step solution

1. Find the bag concentration in mcg/mL

1000 mg × ( 1000 mcg ÷ 1 mg ) ÷ 100 mL

= 10000 mcg/mL

2. Dose per minute: multiply the rate by the patient's weight

5 mcg/kg/min × 65 kg

= 325 mcg/min

3. Convert to mcg per hour

325 mcg/min × ( 60 min ÷ 1 hr )

= 19500 mcg/hr

4. Divide by concentration so mcg cancels, leaving mL/hr

19500 mcg/hr × ( 1 mL ÷ 10000 mcg )

= 2 mL/hr