Question

70kg 250mg dose to infused on 250ml at 6mcg/kg/min. what will it be set per ml/hr

Answer 1

1. To calculate the millilitres/hour we first need to work out what dose is contained in one millilitre of the infusion dosage. We can do this by dividing the volume of the dosage by the weight of the medicine it contains. In this case 250ml/250mg = 1ml/mg. Therefore, 1ml of this infusion solution contains 1mg of drug
2. We then need to calculate the dosage per weight of the patient and convert this into milligrams (since the infusion strength available is in milligrams/mililitre). For a 45kg patient the dose required would be 70kgx 6 micrograms/kg = 420 micrograms. Converting this into milligrams would give 0.42mg (420/1,000); this amount of drug is required per minute. then in 1 hour , 0.42*60=25.2mg drug is required.
3. Using the infusion strength, you know that 1ml would administer 1mg of drug, so 25.2ml would administer 25.2mg. We would therefore set the infusion rate as 25.2ml/hour (22.5mg/1, where 1 is the strength of the dosage in ml/mg).