Intravenous infusion is a calculation which ensures that the total medicine needed by the patient is given at the required rate.
So they are a few things we need to know:
- The total dose of medicine required by the patient?
- How much of the drug we need to add to the IV infusion bag?
- Is there is a maximum infusion rate the medicine can be given?
- What is the rate? That is to say, how many mLs per minute needs to be administered to the patient
Drug Y is required by the patient at a rate of 1200mcg/Kg with the patient weighing 60kg.
250mg of Drug Y is reconstituted in 5mL then made up to a 250mL 0.9% sodium chloride infusion bag.
How many mLs of Drug Y infusion bag solution is required to treat this patient? Drug Y is given at a maximum infusion rate of 40mg/hour. How many minutes will this be administered over?
Lets break this question down with the following:
Step 1: What is the total dose of Drug Y needed by the patient?
1200mcg/kg is the required dose. Which is the same as 1.2mg/kg.
The patient weighs 60 kg.
So, 1.2mg x 60 = 72mg
The total dose required by the patient will be 72mg of Drug Y
Step 2: What is the concentration of Drug Y in the infusion bag?
250mg of Drug Y is reconstituted in 5mL then made up to 250mL of 0.9% sodium chloride infusion bag.
So this will be 250mg in 250mL of 0.9% sodium chloride.
Note the 0.9% strength of sodium chloride is irrelevant here.
The infusion bag will therefore contain: 250mg/250ml which is the same as 1mg/1ml
Step 3: How many mLs of Drug Y solution is required to treat this patient?
As in step 1 the total dose required for the patient is 72mg and the infusion bag contains 1mg/1mL of Drug Z.
Therefore how many mLs of the infusion bag would we need to give the patient if the dose of Drug Z is 72mg ?
72mL of the infusion bag will contain 72 mg of drug Z.
The patient requires 72mLs of Drug Z solution
Step 4: How many minutes will this be administered over?
Drug Y maximum infusion rate is 40mg/hour same as 40mg/60mins.
We need to give 72mg to the patient.
40mg/60minutes can be simplified down to 10mg/15 mins
10mg/5mins X 70 = 70mg/105mins
10mg/15mins can be simplified down to 1mg/1.5minutes
so 2mg would be 2mg/3minutes
70mg/105min + 2mg/3mins = 72mg/108mins
Therefore the total time of Drug Y administration would be 108 minutes
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