Question

MD order: 250 mg of a medication in 500 mL D5W Instructions : Infuse medication at 10mcg / kg / min Drop factor : 15gtts / mL
Client's weight : 140
Calculate the flow rate. Show all work using dimensional analysis

Answer 1

To calculate the flow rate, we need to find the total dose of the medication and divide it by the infusion time.

Step 1: Convert the weight to kg
140 lbs = 140/2.2 kg ≈ 63.64 kg (rounded to two decimal places)

Step 2: Calculate the total dose of the medication
Total dose = 10 mcg/kg/min × 63.64 kg × 60 min
Total dose = 10 × 63.64 × 60 mcg
Total dose = 38184 mcg

Step 3: Convert the total dose to mg
1 mg = 1000 mcg
Total dose = 38184 mcg ÷ 1000 = 38.184 mg

Step 4: Calculate the flow rate using the formula:
Flow rate (gtts/min) = (Total dose × Drop factor) ÷ Volume (mL)

Flow rate = (38.184 mg × 15 gtts/mL) ÷ 500 mL
Flow rate = 572.76 gtts ÷ 500 mL
Flow rate = 1.14552 gtts/mL

The flow rate is approximately 1.15 gtts/min.