Dosage Calculation Question for Healthcare Professionals!

Question

1) A healthcare provider has ordered dobutamine 10 mcg/kg/min IV for your 68 YO patient who weighs 172 lb. The dobutamine is available as 1000 mg/250 mL. At what rate will you set the IV infusion pump?

Wojcik, Bradley J.. Nursing Dosage Calculation Workbook: 24 Categories Of Problems From Basic To Advanced! (Dosage Calculation Success Series) (p. 122). Nurse Superhero. Kindle Edition.

Answer 1

Answer 2

1. First convert the patient's weight to kg. The ratio of kg to pounds is 1 kg / 2.2 lbs
2. 172 lbs ( 1 kg / 2.2 lbs) = 78.2 kg
3. The dose ordered is 10 mcg/kg/min so we want to know how much drug to give per minute. For ever 1 kg the patient needs 10 mcg of dobutamine. The ratio is 10 mcg dobutamine / 1 kg
4. 78.2 kg (10 mcg dobutamine / 1 kg) = 782 mcg, so we need to give ~780 mcg of dobutamine per minute
5. We need to convert this to mg, since the available dobutamine strength is in mg/ml.
6. 780 mcg/ 1,000 = 0.78 mg
7. Dobutamine is available as a ratio of 1000 mg dobutamine / 250 mL.
8. 0.78 mg dobutamine (250 ml / 1,0000 mg) = 0.195 ml, so we need to infuse 0.195 ml per minute.
9. Multiply this by 60 minutes to get the hourly rate.
10. 0.195 ml/min x 60 minutes = 11.7 ml / hour

Answer 3

Hello student,

This is a very typical question for healthcare students and yet a very important one. It's simple and direct, however, it could turn out tricky if you miss the units.

The question asks to find the rate at which the IV pump should be set so that the patient receives the right amount of the dose, based on his body weight.

Step 1: Find the dose required by the patient:

Patient weight: 172 lbs. However the dose is given as 10 mcg/kg/min (which is in Kgs)

So convert lbs to Kgs: 172/2.2 = 78.18 Kgs (1 Kg = 2.2 lbs)

Since per Kg dose of the drug is 10 mcg/min. Therefore, the patient requires: 78.18 x 10 = 781.8 mcg/min.

Now, dobutamine is available as 1000 mg/250 mL (which is mgs and not mcg).

Therefore, we convert the mcg dose to mg: 781.8 mcg/min = 0.7818 mg/min (1 mg = 1000 mcg)

Now, most IVs are given for a period spanning in hours. Therefore, the patient dose is 0.7818 x 60 = 46.9 mgs/hour.

Since, dobutamine is available as 1000mg/250 mL. Therefore, we need to calculate the volume of this drug to be administered to the patient through 1 hour, to deliver 46.9 mgs.

Therefore, (46.9 x 250)/1000 = 11.7 mLs/hour

Hope this helps. Good luck!

Abbas