Download Prescribing IV Infusions

Prescribing IV Infusions
CWFS
Problem areas
• •Calculating infusion rates
• •Completing the form
• •Awareness of appropriate volumes and
dose
• •Compatibilities and the BNF
Prescribing infusions
• •Prescribe on correct chart
• Once only section of prescription chart for
injections (loading doses / IV bolus doses)
• Drug kardex for multiple boluses
• IV chart for infusions
• •Infusion fluid and strength
• No abbreviations
• What is in the bag before you add anything?
Volume
• Number of mls before you add anything
N.B. for continuous infusion max 2-3L
per day
•Additive and dose
The drug you are adding and the total
number of mg or units to add to the bag
•Rate in ml/hour
Injections/infusions
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•IV = fast injection/bolus
Usually just a few millilitres
•Slow IV = over 5-10 minutes
Usually <10ml unless by syringe driver
•Infusion = >100ml over at least 20 minutes
Rate has to be monitored
Compatibilities
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•BNF Appendix 6: Intravenous additives
Not exhaustive
Ask Pharmacy
•Check appendix carefully as not all drugs
are compatible with sodium chloride 0.9%
Practice 1
• •Mr.Ben is a 37 year old man admitted with a paracetamol overdose.
His plasma-paracetamol concentration (mmol/litre) indicates that he
requires acetylcysteine. He weighs 67kg.
• Prescribe on an intravenous prescribing sheet the acetylcysteine
regimen that he requires so that it can be administered
• •BNF Acetylcysteine
• Adult and Child, initially 150mg/kg over 15 minutes, then
50mg/kg over 4 hours then 100mg/kg over 16 hours.
• Dilute requisite dose in glucose 5% as follows: Initially 200ml
given over 15 minutes, then 500ml over 4 hours, then 1 litre
over 16 hours
Practice 1 -Answer
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•Step 1–calculate the dose over the period
of time you require (weight 67kg)
150mg/kg over 15 minutes = 10050mg
50mg/kg over 4 hours = 3350mg
100mg/kg over 16 hours = 6700mg
•Step 2–follow BNF instruction for dilution
initially 200ml given over 15 minutes
then 500ml over 4 hours
then 1 litre over 16 hours
Practice 1 -Answer
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•Step 3–calculate the rate
Rate = Volume / Time
•10050mg in 200ml dextrose 5% over 15 min
•3350mg in 500ml dextrose 5%over 4 hours
Rate = 500ml/4hours = 125ml/hour
•6700mg in 1 litre dextrose 5%over 16 hours
1l = 1000ml
Rate = 1000ml/16hours = 62.5ml/hour
IV practice 2
• •Mrs.Smith is a 28 year old epileptic who you wish to initiate on
sodium valproate. She is 50kg and currently unable to swallow.
• •BNF No. 53: Sodium valproate
• 􀂃Initiation of valproate therapy, by intravenous injection (over
3–5 minutes), 400-800mg (up to 10mg/kg) followed by a
continuous intravenous infusion up to max. 2.5g daily.
• •You wish to give her an initial loading dose of 4mg/kg followed by
an intravenous infusion of 1.6g over 24 hours
• •Prescribe the required loading dose and intravenous infusion that
she requires
IV practice 2 -answer
• •Step 1–calculate the initiation dose
• 4mg/kg = 4x50 = 200mg over 5 minutes
• Step 2 –What infusion fluid and volume do you
require?
– BNF: Glucose 5% or sodium chloride 0.9%, any
suitable volume.
– Pick one: Sodium chloride 0.9% 500ml
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•Step 3–Convert to ml/hour
500ml over 24 hours
= 20.8ml/hour
5.Prescribe it
Sodium chloride 0.9% 500ml
Sodium valproate 1.6g
Rate 20.8ml/hr
IV practice 3
• •Mr. Taylor is a 45 year old man requiring
inotropic support after infarction. He weighs 60
kg.
• •The consultant says he needs to be prescribed
dobutamine 2.5microgram/kg/min at a
concentration of 500micrograms/ml and give it in
glucose 5% 500ml.
• •Prescribe the IV prescription that he requires
IV practice 3 -answer
• •Step 1 –calculate total amount of dobutamine in bag
• 500ml at 500mcg/ml
– = 250000micrograms =250mg
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•Step 2 -calculate the dose over the period of
time you require
2.5mcg/kg/min
60kg
• 2.5x60x60
• = 9000mcg/hour = 9mg/hour
IV practice 3 -answer
• Step 3 –calculate the rate
• 9mg/hour
• 500mcg/ml
• Rate = 9000
• 500
• = 18ml/hour
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4.Prescribe it
Glucose 5% 500ml
Dobutamine 250mg
Rate 18ml/hr
Self-check for IV
prescriptions
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•Correct chart?
•Correct drug?
•Amount of drug in infusion?
•Volume and name of diluent?
•Rate and/or duration of administration?
•Route of administration?
•Dated and signed?
Calculations
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•Read the question carefully
•Extract all information from question
Which information is given?
What are you asked to calculate?
•Get as much info as possible from BNF
(dosage, administration, etc.)
Appendix 6: Intravenous additives
Express question as an equation
Safety Check
• Consider asking somebody else to check
your work, especially if tired / stressed