Transcript Document

Module (1) – Intravenous
Medications
IV access
IV Drug administration
Calculating Drug doses
Introduction
This module, as with the other four, is designed so
you may do the steps at any time over the next six
months. You may re-visit the website whenever
you wish, download the entire module, print it off
or indeed repaper your bathroom with it.
However the skills and knowledge contained
within it are essential to being a PRHO so you
should be familiar and competent with them all
before you qualify. They are often assessed and
may be included in an assessment prior to finals.
You should include all notes and answers in your
PPD folder which will be appraised but not
formally assessed
Aims and Objectives
This module is designed to facilitate your
learning around intravenous medications.
By the end of this module you should be
• Aware of the steps necessary in obtaining
IV access.
• Aware of the steps necessary to draw up and
administer an intravenous drug.
• Able to calculate the dose of an IV
medication before administering it.
Challenging Practice
Before you start this part of the module
• Write out the generic steps you carry out
every time you perform a procedure e.g.
gain consent; wash hands
• Write out the specific steps for the
following procedures
- Gaining IV access
- Drawing up an IV medication
- Administering an IV medication
Part (a) – Skills practice
In order to perform the skills in this part of the
module – you will need to be in a skills centre
with access to :• A mannekin arm
• IV access set
• IV medication (you can use saline or similar)
• The drug chart provided
You will need to think what specific items you will
need for each skill
Generic approach to all procedures
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Introduce yourself with name and role
Check you have the correct patient by introduction and ID band (if in-patient)
Explain procedure and gain verbal consent – ‘Is that alright / OK?’
Check you have ALL the appropriate items to do the procedure and they are in
working order.
Wash hands prior and after procedure
Position the patient for ease of procedure and their comfort; Ensure they are able to
maintain this position for the duration of the procedure.
Proceed explaining and reassuring as you carry out the procedure.
Once completed thank the patient AND reposition them comfortably whilst
maintaining their dignity.
CLEAR UP THE MESS! Place sharps and other similar items e.g. bloodied items,
into the sharps bin.
Explain / Confirm to nursing staff what you have done and what if anything you
would like done as a result e.g. ‘I have re-sited a cannula in the left arm to be used for
IV antibiotics’; Indwelling catheter – ‘Please measure and record hourly urine
output’; Agree any observations that may need to be done and other issues – NBM;
Analgesia; Possible complications.
Record procedure in the notes – include any difficulties and possible complications.
Accurately record any conversation with patient and relatives around these problems.
Siting a Peripheral Intravenous Cannula
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Follow generic guidelines for all procedures
For this trick you will need
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Tourniquet
Gloves
Appropriate sized iv cannula
Steret
Cannula dressing e.g. vecafix
IV saline flush – saline; syringe and ‘drawing up’ needle
Sharps bin
Having gained verbal consent, place patient’s arm comfortably on bedside or similar.
Ensures all correct equipment present; Draw up saline flush
Put on gloves
Place tourniquet on arm
Identify appropriate vein
Clean area with steret
Warn patient of sharp jab
Insert cannula into vein at approximately 45 degrees; Look for flash back.
Undo the tourniquet
Remove introducer whilst advancing the cannula; once sited cap it.
Fix cannula to skin with appropriate dressing
Flush the cannula using the saline flush.
Dispose of sharps and other items correctly.
Explain to staff what the cannula is to be used for and where it is sited.
Explain (when challenged) what they would do if the cannula is not sited successfully.
Drawing up an Intravenous Medication
This part of the procedure is often assessed
in isolation but you should think about it as
part of the administration of an IV
medication; You will need to check you
have the correct patient, explain to them
what you are going to do, check they have
no contra-indications or allergies to the
medication. Then you can draw up the drug.
Drawing up an Intravenous Medication
Check
• You have the correct patient and drug chart.
• The drug chart for drug, dose, route and time of administration.
• You have all the necessary equipment
- ‘Green’ needle; appropriate syringe; the drug ampoule; steret; saline flush and for
powdered preparations - mixing solution i.e. saline, water for injection or dextrose.
• Drug against drug chart and ensure it is in-date and correct dose
• Mixing solution is correct and in-date
For pre-mixed solutions simply draw up the medication into an appropriate syringe
For powdered preparations
• Tear off protective cover from drug ampoule and clean with steret
• Draw up appropriate volume of mixing solution
• Insert needle into drug ampoule and inject small volume (1-2 ml) of solution; never
force the solution against pressure (unless you want to wear it!)
• Gently mix the powder and solution; You may need to add a little more solution to
completely dissolve the powder. DON’T shake as this will lead to excessive bubbles and
froth
• Once dissolved, draw the mixed solution back into the syringe; If you inject a little air
from the syringe into the ampoule you will find the solution is drawn back into the
syringe.
• Once all the solution is drawn up – make sure it is mixed and eject any air bubbles.
• Keep the syringe hub covered until you are ready to inject the medication
Administering an intravenous medication
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Introduce yourself with name and role
Check you have the correct patient by introduction and ID band
Explain procedure and gain verbal consent – ‘Is that Ok?’
Check they have no
– Known drug or other allergy history
– Contra-indications to the intervention
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Check the drug against the prescription
Check the drug is ‘in date’ ie not time expired
Administer drug slowly – usually over approximately 1 minute.
Sign for it on the drug chart.
Agree with nursing staff what you would like them to do next –
observations, monitor response, potential side effects or complications.
• Ask yourself ‘Are there any sequelae I need to consider as the PRHO?’
e.g. Monitor levels, Check bloods (FBC - post transfusion; U+Es –
post IV diuretics, ACEI).
Calculating doses of IV medications
• When calculating the doses of any medication
whether it be tablets, elixir, IV or IM injections or
infusions it is essential to get the dose and the
units correct. By following simple rules you
should be confident in your ability to get the dose
correct every time – getting it wrong can be fatal!
• For many of you with mathematic backgrounds,
calculation using algebra is relatively easy. The
following use of dimensional analysis may seem
very basic but will keep you amused whilst the
rest of us mere mortals struggle
Dimensional Analysis
Dimensional analysis is commonly used by chemistry and physics
students to ensure they don’t make basic calculation errors when using
lots of values in an equation with different units; Each time one
converts one unit to another we use a conversion factor, which we will
call the dimensional analysis conversion factor (DACF) e.g 450g to kg
– the DACF = 1000g / 1 kg
Thus 450g / Xkg = 1000g / 1 Kg
XKg = 450g x 1 Kg
1000g
= 0.450 Kg
Dimensional analysis ensures that both sides of an equation are
‘singing from the same hymn sheet’. I.e. The units on both sides are
the same. By cancelling the units above and below the line, the units
you are left with on one side should equal those of the value you are
seeking. If they don’t match, you have mucked up somewhere!
However it will not ensure your maths is correct.
Dimensional analysis
Example One
Farmer Giles is a sheep farmer. He is required by the
Ministry of Agriculture to wash his sheep in a new wool
protector. He is told by the ministry literature that if he
washes 20 sheep per hour for 12 hours per day he can wash
his entire Flock in 3 days.
Farmer Giles keeps his sheep in separate areas of the farm
and uses his own nomenclature for his groupings. There
are 5 sheep in a ‘BOX’, 5 Boxes in a ‘CORRAL’ and 5
Corrals in a ‘FLICK’. He estimates he has 10 FLICKS
around the farm completing his FLOCK. Please calculate if
the Ministry literature is correct.
Well did you get it correct? – Here’s the solution
using dimensional analysis
20 sheep / hour = How many Flicks
X Flicks = 20 sheep x IBox x 1 corral x 1 Flick
1 hour
1 hour x 5 sheep x 5 Box x 5 corral
Note: the units all cancel each other out so you know you have
flick/ hour as the units which means the equation is ok
= 0.16 FLICK / hour
If he works twelve hours per day for three days
= 0.16 x 12 hours / day x 3 days
= 1.92 x 3
= 5.76 Flicks in 3 days
If he has 10 flicks around the farm he will be there a few more
days and thus he tells the Ministry to go take a running jump!
If that one confused you – try this one borrowed from
www.wine1.sb.fsu.edu/chm1045/notes/Intro/Dimanal/Dimanal.htm - Dr
Michael Baker – a teacher with a similar outlook on education!
Dimensional analysis for party planning…
If you have ever had a party you have used dimensional analysis. The amount of
beer (or soft drinks) and munchies you will need will depend on the number of
people you expect. For 30 people you may estimate you need to go and buy
120 bottles of beer and 10 large pizzas (obviously not a medic party!) How did
you guestimate these numbers? Here’s the dimensional analysis.
4 bottles / person and 1/3 of a pizza per person
30 persons x (4 beers) = 120 beers
person
30 persons x (0.333 pizza) = 10 pizzas
person
But should you buy beer in six packs or cases? – 1 case = 4 six packs = 24 Beers
120 beers x 1 six pack x 1case = 5 cases
6 Beers
4 six packs
1 case / 4 six packs = 5 cases / x six packs = 20 six packs it’s easier to carry cases so
buy the cases!
Dose of medication = Rate of Infusion x Concentration
For each of the examples below you will need to use
the following equations. Please refer back to them as
you work through the problems
Dose of medication = Rate of Infusion x Concentration
Where:
Dose =
volume or mass or units E.g. mcg / kg / min
unit time (usually minutes)
Rate =
volume in ml = ml per hour unless infusing
unit time (Hrs)
an infusion in less than 1
hour
Concentration = dose available I.e. mg or mcg per ml
volume available
Infusion Rate
From Dose = Rate x Concentration
Rate = Dose x
1
Concentration
If Concentration e.g. 250 mg / 1000ml
Thus Rate (ml) = Dose x 1000ml
Hr
250mg
This is a useful equation to remember for
drip rates which are set in ml/Hr when run
through a pump
Try this one for size ….
You are asked to set up an infusion with a
pre-mixed bag of Phenytoin. The bag
contains 1000mg / litre and you need to
give an infusion of 500mg over 6 hours.
What rate will you set the pump at (ml/hr) –
Try to use multidimensional analysis to
ensure your units are correct.
Ooh! – Suits you Sir!
Rate Xml = 500mg x 1000ml (Units are correct)
Hr
6Hr
1000mg
= 83.3 ie 83ml/Hr
Calculate the doses required for the following medications
(1) You are asked to give a patient 3mg/kg of
gentamicin once per day. The patient weighs 83kg.
How much will you give him?
(2) A patient is to be given 70mg of clexane. The
only preparation contains 120mg in 5mls. What
volume of clexane preparation will you draw up?
(3) A 50Kg patient is receiving 2g of killabug every
eight hours. The recommended dose is 100 –
300mg/kg/day. Is the prescribed dose appropriate?
Hopefully you felt I was insulting you!
(1) 83Kg x 3mg = 249 mg Total
(2) If in 5mls there are 120mg – How many mls are needed
for 70 mg?
5mls = Xmls Thus X = 70mg x 5mls = 2.92mls
120mg 70mg
120mg
Thus you would draw up 3 mls – as this is most appropriate
volume
(3) 2g / 8 hourly = 6g / 24 hours
How many milligrams / Kg / 24 hours?
6g x 1000 mg x 1
= 120 mg / kg / 24 hours
24hrs 1g
50Kg
Thus the dose is appropriate
Try these for size …
(1) You are asked to draw up and give 0.25 mg of Digoxin.
The vial contains 500mcg per ml. How many ml will
you administer?
(2) A patient is prescribed Amoxycillin syrup 500mg tds.
The syrup is 125mg/5ml. How many ml will you
prescribe per dose?
(3) A patient is prescribed 250 mg of Augmentin IV. The
nurse tells you that there are 600mg in the 5ml vial. How
many ml will you draw up?
(4) A patient is prescribed Hy-life 400mcg subcut. You can
only find a vial with 0.5mg / 5ml. How many ml will
you administer?
Just taking the Michael aren’t I?
Answers – You will need to show your workings
(1) 0.5ml
(2) 20ml
(3) 2.1ml
(4) 4ml
And finally on this infusion front ..
You are asked to draw up and give an
infusion of gentamicin over 45
minutes. The patient is to receive 3 mg
/ Kg and weighs 100Kg. The infusion
is to be made up in a 50 ml bag of
D5W.
What is the rate of the infusion set in
ml/Hr?
Either …Or ….
Rate ml = (3 x 100) mg x 50ml x 60 mins
Hr
45 mins (3 x 100mg)
= 50 x 60 = 66.7 = 67 ml / Hr
45
Or
If 50 ml = Xml Thus X = 50 x 60 = 67 ml / Hr
45 mins 60mins
45 mins
Last Infusion calculation for 30 Km
An infusion of Kilabug is made up to
be 2g in 500ml D5W. It should run at
3mg / minute. What rate will you set
the infusion pump in ml/Hr?
Last Answer Saloon ….
An infusion of Kilabug is made up to be 2g in 500ml D5W. It
should run at 3mg / minute. What rate will you set the
infusion pump in ml/Hr?
(Did you use the sexy Multidimensional analysis or was it
just too easy??)
Rate (ml) = 3mg x 500 ml x 60 mins x 1g = 90 = 45 mls
Hr 1 min 2g
1hr 1000mg 2
Hr
And now for something completely different ..
When you have been on anaesthetic or ITU attachments have you ever wondered what the 1:
10,000 or 2% by volume actually means?
Well let me put you out of your misery …
When a solution is written as 1:X,000 = Mass (g) : Volume (ml)
Thus 1:1000 = 1g per 1000ml
= 1g x 1000mg per 1000ml
1g
= 1000mg per 1000ml
I.e 1mg per 1ml = 1mg / ml
So 1:10,000 is 1mg per 10 ml
A 2% solution means Mass (g) per 100ml volume
Thus 2% = 2g per 100ml
2g x 1000mg per 100ml
1g
I.e. 2000mg per 100ml = 20mg per ml = 20mg /ml
Here’s some to tickle your ventricles
(1) How many ml of 1:10,000 ADR will you draw up to
contain 0.25mg ADR?
(2) How many mg of ADR in 4ml of 1:1000 ADR?
(3) How many mg of Lignocaine are there in 25ml of 2%
solution?
(4) You are asked to mix up a solution of Lignocaine with
250mg of Lignocaine 250ml. What is the mass by
percentage (X%) solution you have mixed?
(1) How many ml of 1:10,000 ADR will you draw up to contain 0.25mg ADR?
Answer 1g per 10,000ml = 1mg/10ml
1mg = 0.25mg
10ml
X ml
Thus you should draw up 2.5ml
(2) How many mg of ADR in 4ml of 1:1000 ADR?
Answer 1g : 1000ml = 1mg / ml
Thus 4mg of ADR in 4ml
(3) How many mg of Lignocaine are there in 25ml of 2% solution?
2% = 2g / 100ml = 2000mg per 100ml = 20mg per ml
Thus in 25 ml - 25x 20 = 500mg
Thus 500 mg Lignocaine
(4) You are asked to mix up a solution of Lignocaine with 250 mg of Lignocaine per
250ml. What is the mass by percentage solution you have mixed?
250mg per 250ml = 100mg in 100ml = 100mg x 1g = 0.1g: 100ml
1000mg
Thus 0.1g / 100 ml = 0.1% solution
Answers (1) 2.5ml (2) 4mg (3) 500mg (4) 0.1%
For further challenges …
Ability of hospital doctors to calculate drug
doses – Rolfe S. and Harper NJN. – BMJ
1995, 310, 1173 -1174
Learning Outcomes
By the end of this module:
(1) You should have practiced
•Inserting an intravenous cannula
•Drawing up and administering an intravenous medication
(2) You should be able to calculate doses to be administered,
infusion rates and mass by volume (1:X,000) and mass by
percentage volume (X% solutions).
You will need to continue to practice these skills on all of
your firms. They are necessary to be a competent PRHO and
they may be assessed during this final year.
You will learn further skills around intravenous drips and
infusions in module (4)
Recommended websites
www.wine1.sb.fsu.edu/chm1045/notes/Intro/Dimanal/Dimanal.html
www.-isu.indstate.edu/nurs/mary/mathprac.html
www.classes.kumc.edu/son/nurs420/CalculatingDrugDosages.html
www.cs.jcu.edu.au/~michael/web/Sections6.html