BSc (Hons) Midwifery
Pre registration Student
Numerical Assessment in practice
workbook
Name:
Intake group:
The purpose of this workbook is to help you practise your
Numeracy skills. These are required by the NMC for the
achievement of Practice Learning Outcomes relating to
competence in numeracy, calculations and the safe
administration of medicines. This workbook may be used
as supportive evidence of your preparation, and therefore
can be used in your discussions with your
assessor/mentor.
2
Advice to Students
Work your way through this workbook, working on the practice questions as
you go. The answers are provided but try not to look at them before you have
completed the exercises. Always show how you have worked out a particular
question – this helps you identify any errors you might make, and could help
you, and a reviewer, understand how you have arrived at the answer.
Try wherever possible not to rely on using a calculator. By working things out
on paper and using your own numeracy skills, you are more likely to be able
to spot where an answer seems to be wrong – for example, you know ‘in your
head’ that the answer is likely to be 3 tablets and yet the calculator answer
suggests 12.
Remember
“For entry to the register, programme providers will use the ESC’s
(Essential Skills Clusters) to inform the nature and content of numerical
assessment where a 100% pass mark is required and all assessment
must take place in the practice setting. The number of attempts is to be
determined by the education provider.” NMC Circular 07/2007.
The Essential Skills Cluster states:
Summative health related numerical assessments are required to test skills
identified (*) within the ESCs that encompass calculations associated with
medicines. A 100% pass mark is required and assessment must take place in
the practice setting.
Medicines management in the context of midwifery practice is
predicated on a partnership approach between the woman and the
midwife. Its purpose is to provide therapeutic intervention when
necessary throughout childbirth to facilitate a positive outcome.
In order to meet the NMC’s directive that students’ numerical assessment
must take place in the practice setting, it is proposed that students meet the
following requirements:
First Progression Point (End of year 1 midwifery modules)
Competence statement:
safely’
‘Undertake medicinal product calculations
3
ESC skill
Competent
in
calculating
common
dosages of
medicinal
products
used in
normal
midwifery
practice
Requirement
1. Completion & pass of
on-line numeracy
assessment
2. Pass of Essential Skills
Cluster in clinical practice
Assessment
Students must achieve
19 out of 25 questions
and the test may be
taken a maximum of 5
times in order for the
standard to be achieved.
Evidence to be assessed
within practice and will
include a drugs
calculation test.
Pass
mark
75 %
100%
As preparation for the practice assessment to be conducted by the mentor,
students will be required to show evidence of achievement in the UWE on-line
numeracy test. Students must present the on-line results prior to
undertaking and demonstrating their achievement of the essential skills
cluster to their Sign-off Mentor at progression point one.
At the end of year two students should show Completion & pass of online Numeracy assessment. 80% (20 out of 25 questions.) in preparation
for year three.
Second Progression Point: for entry to the register. (End of year three
midwifery modules).
Competence statements:
1. ‘Within the parameters of normal childbirth, ensure safe and
effective practice through comprehensive knowledge of medicinal
products, their actions, risks and benefits including the ability to
recognise and respond safely to adverse drug reactions and
adverse drug events’.
2. ‘Undertake medicinal product calculations safely’.
ESC skill
Requirement
Assessment
1. Manages
drug
administration
and safely
monitors its
effect.
1. Completion & pass of
on-line numeracy
assessment.
Students must achieve
20 out of 25 questions
and the test may be
taken a maximum of 5
times in order for the
standard to be achieved.
Evidence to be assessed
within practice and will
include a drugs
calculation test.
2. Calculates
accurately the
medicinal
products
frequently
2. Pass of Skills Cluster
in clinical practice to
include administering of
medicinal products
safely via appropriate
routes including specific
Pass
mark
80%
100%
4
encountered
within the field
of practice.
requirements for
neonates.
As preparation for the practice assessment to be conducted by the mentor,
students will be required to show evidence of achievement in the UWE on-line
numeracy test. Students must present the on-line results prior to undertaking
and demonstrating their achievement of the essential skills cluster to their
Sign-off Mentor, at progression point two for entry to the register.
Students must achieve a pass in both components in order to meet the NMC
requirements. This Numeracy related workbook is available as an additional
supportive resource for students at the start of the programme. Whilst this is
not assessed by mentors, the Sign-off Mentor may utilise it as further
evidence in making their judgement of the assessment of the student’s
numerical competency.
Summative health related numerical assessments are required to test skills
identified (*) within the ESC’s that encompass calculations associated with
medicines. A 100% pass mark is required and assessment must take place in
the practice setting
Thanks to colleagues for help in preparing this pack
Author : Sue Davis
Critical reader : Dorothy Cook
5
The Metric System
SI units
This is another name for the metric system of measurement. The aim of
metrication is to make calculation easier than with imperial measurements.
SI stands for System international and is now recognised as the standard
system for measurement in most disciplines around the world. It was
introduced to the NHS in 1975.
Weight
1 kilogram
1 gram
1 milligram
=
=
=
1000 grams
1000 milligrams
1000 micrograms
1 microgram =
1 nanogram =
1000 nanograms
1000 picograms
Recognised abbreviations of these units are:
kilogram = kg
microgram = mcg
gram = g
nanogram = ng
milligram = mg
(Abbreviations for microgram and nanogram should not be used in
prescribing.)
Volume
1 litre
=
1000 millilitres
Recognised abbreviations of these units are:
litre = L
millilitre = ml
Height
6ft 2inches = 1.88 metres
5ft .3inches = 1.6 meters
Converting height
1 feet = 30.5 cms
1 inch is 2.5cms
Height conversion =
Feet to height X30.48 centimetres to feet x 0.328
Inches to cms x 2.54
centimetres to inches x0.3937
(Lapham and Agar 2003 )
6
Strength of a solution
This can be expressed as:
a) % weight versus volume = number of grams per 100mls
e.g. sodium chloride 30% = 30g in 100mls
b) Parts e.g. Adrenaline 1 in 1000 = 1g in 1000ml = 1mg in 1ml
Adrenaline 1 in 10,000 = 1g in 10,000ml = 1mg in 10mls
Converting Larger Units to the Next Smaller Unit
To convert a larger unit to a smaller unit you need to multiply by 1000.
Example:
Convert 5g to milligrams:
Convert 0.25kg to grams:
5 x 1000
0.25 x 1000
=
=
5000mg
250g
Practice:
Convert the following to micrograms
1. 0.5mg
2. 0.0625mg
3. 0.25 mg
Convert the following into nanograms
4 0.25 mcg
5 0.0625 mcg
6 1.5mcg
Converting Smaller Units to the Next Larger Unit:
To convert a smaller unit to the larger unit you divide by 1000.
Example:
Convert 6000g to kilograms :
Convert 325mg to grams:
6000/ 1000 =
325/ 1000
=
6kg
0.325g
7
Practice:
Convert the following into milligrams
7 300mcg
8 75mcg
9 187.5 mcg
Dealing with Decimal Points
25
x 0.5
____
12.5
25
x 0.05
_____
1.25
There is one number
after the decimal point
There are two numbers
after the decimal point
in the sum therefore one
in the sum therefore two
after the point in the answer.
after the point in the answer.
Practice
10.
2.5 x 100 =
11.
0.3 x1000 =
12.
7.5 x 30
=
13.
36  60 =
14.
125 550 =
15.
5.5  50 =
16.
250  1000 =
8
Fractions
To simplify fractions divide the top number into the bottom number, which
divides into both of these exactly.
This number is called a common factor.
e.g.
24 = 2 (both numbers have been divided by 12, which is a common factor
36
3 used in this fraction).
This could also have been completed in several steps:
24
36
= 12
18
(common factor is 2)
= 4
6
(common factor is 3)
= 2
3
(common factor 2)
Then
12
18
Then
4
6
Converting Fractions to Decimals
In order to convert a fraction to a decimal, you need to divide the top number
by the bottom number.
e.g.
1 =
2
2
(divide the bottom number into the top number)
0.5
1.0
= 0.5
Practice
17.
3
9
=
18. 6 =
12
21.
3
4
=
22.
1
100
19. 25 =
75
=
20.
7
8
9
Fluid Requirements
First 10kg
= 100ml/kg
Second 10kg
= 50ml/kg
Subsequent
= 20ml/kg
Practice:
Using the above formula calculate the daily fluid requirements
23. 6.2kg
24. 3.8kg
25. 29kg
Unit Conversion
26.
4000 micrograms = mg
6mg
2 litres =
0.24 micrograms =
ml
= micrograms
75 mg =
grams
187.5 micrograms =
650 ml =
litres
0.25 micrograms =
nanograms
mg
nanograms
10
Oral Liquids
A sedative produced in concentration of 500mg/5mls. Calculate the volumes
for the following doses:
27.
Dose Prescribed (mg)
250
350
65
150
750
Volume Required (ml)
Ranitidine comes in a concentration of 150mg in 10mls; calculate the
volumes needed for the following doses:
28.
Dose Prescribed (mg)
25
16
35
65
150
Volume Required (ml)
Drug Dosages for Injection
Volume Required = Dose prescribed
Dose you have
available
x
volume of stock solution
e.g.
A patient is prescribed cortisone 40 mg. The ampoules contain 50 mg in 2mls.
Calculate the volume required.
Using the formula
40 mg x 2ml
50mg
= 40 x 2
50
1
11
Answer =
8
5
= 1.6 mls
Practice
29. If 50 m.g of a drug is contained in 10ml of solution, how much must be
given to give 25mg?
30. Prescribed: Erythromycin 270 mg
Available:
300mg in 10 mls
31. Morphine 9 mg is required and the stock solution is 15mg in 1 ml. How
much is required?
32. The ampoule reads 500micrograms in 5 mls of solution. How much
solution is needed to give 10 micrograms?
33. Sally Ali is in hospital following surgery. She has an intra-venous infusion
of 1 litre normal saline every 8 hours; she has vomited twice (30ml and
45ml); and her catheter has drained 1 300ml of urine during the last 12
hours.
What is the difference between Sally’s fluid intake and output (in ml) over the
last 12 hours ?
12
34. Jane, who has a bi-polar disorder, is going through a period of significant
depression and there is some concern that her fluid balance is not being well
maintained (see chart below for details).
a) Complete this table to give the daily total for both intake and output
FLUID INTAKE (millilitres)
TIME
3rd March
4th March
5th March
08:00
09:00
10:00
11:00
12:00
13:00
14:00
15:00
16:00
17:00
18:00
19:00
300
300
250
DAY
TOTALS
20:00
21:00
22:00
23:00
00:00
01:00
02:00
03:00
04:00
05:00
06:00
07:00
FLUID OUTPUT (millilitres)
6th March 3rd March 4th March 5th March. 6th March
250
280
280
230
250
250
125
135
225
300
135
133
240
270
140
152
200
300
250
175
220
370
230
270
250
525
225
250
300
450
330
125
100
380
150
350
320
400
300
NIGHT
b) What
TOTALS
is Jane’s average daily fluid intake over these 4 days?
24
c)HOUR
What
TOTALS
is Jane’s average daily fluid output over these 4 days?
35. d) Jane is thought to be developing a chest infection, so 400mg of an
antibiotic is prescribed, to be administered 6-hourly. The antibiotic comes in a
suspension of 125mg in 5 ml.
How many ml will be needed for all doses over a 24-hour period?
345
13
36 . Susan has regular epileptic seizures but these are reasonably controlled
through the use of medication. Currently she is prescribed Phenytoin in a
suspension which contains 15mg/2.5ml. The initial dose is worked out
according to body weight (3.5mg per kg daily).
a) If Susan is 86kg what would her initial daily dose be (to the nearest 10mg)?
Because Susan’s epilepsy is now generally well-controlled she is actually
prescribed 255 mg Phenytoin a day to be given in 2 equal doses.
b) How many millilitres of suspension should be given in each dose?
Dosage calculations
It is the midwife’s role to ensure the woman is given the correct amount of
tablets which means finding out the amount of drug in each tablet and then
calculating how many tablets to give to the woman.
Sally is prescribed Drug A - 120 mg. but the tablets are only available as
40mg each
How many tablets are required?
The formula is the number of tablets + Amount prescribed
Amount in each tablet
The prescription is the total quantity to be given or what you want.
The availability is the quantity in each tablet or what you have got
So you can use the following formula to remember .
The number of tablets = what you want
What you have got
Answer for this example is 3 tablets
14
Another important point is the need to ensure that the prescribed
amount and the availability are in the same units.
So you may need to convert milligrams into grams or convert grams into
milligrams.
Try the example below.
37. Mrs James is prescribed 350mg of drug A, four times daily for one week.
Drug A is dispensed in tablets containing 175mg.
Mrs James daily dose of drug A in grams is:
Remember in practice it is highly unlikely that you will need to give the woman
more than three or four tablets. So if this is occurring check with the
pharmacist who may be able to advice.
Also note that paediatric doses are usually only half the adult dose.
Intravenous Drugs
The rate of flow of fluid down an intravenous line must be regulated and this is
normally controlled by a machine called an infusion controller. In some case
you may have a giving set that needs you to set the drip rate measured in
drips per minute. It is important that you know which you are dealing with as
some infusion controllers allow you the operator to alter the flow of liquid and
they may also require you to set the flow rate which is measured in millilitres
per hour. And other requires a drip rate. This is normally written on the
machine.
To calculate the flow rate, you need to divide the volume in mls by the
duration in hours.
A woman may be prescribed 500mls Intravenous Infusion (IVI) over 12 hours .
What is the flow rate?
Answer 500 divided by 12 is 41.66ml/hr.
If you do not have the facility to enter decimals, then round to the
nearest whole number the answer would then be 42ml/hour.
15
On some types of flow controller, the size of each drop of liquid given is
governed by the machines internal functions. These are normally fixed at the
factory and cannot be altered for safety.
The constant quantity gives rise to the drop factor which is the number of drops
which make up every millilitre of fluid delivered.
Special paediatric infusion controllers are also available.
The drop rate +Total drops
Time in minutes
If the total volume of fluid is given in millilitres and the drop factor for the
controller is known (written on the machine), the total number of drops which
the woman will receive can be calculated by the expression.
Total number of drops = drop factor X volume in ml
Also if the time is given in hours we can calculate the time in minutes by
multiplying 60 x time n hours.
Drop rate = drop factor x volume in ml
60 x time in hours
38. Calculate the drop rate if the women requires 5% dextrose solution to be
given IV over 12 hours via a machine that has a drop rate of 20.
20 = 20 drops per ml x 500ml =
60X 12 hours
Infant Artificial feeding
This is a further example of the use of formulae
If babies are artificially fed it is important that feeds are made up correctly.
Infants are normally fed on demand, but if the Paediatrician feel it is important
and the condition of the baby requires regular feeds, the infant should receive
150 -200ml/kg body weight /24 hours.
To calculate the volume of feed, values are substituted into the following
equation.
Amount of milk x weight of baby
Number of feeds in 24 hours
16
To calculate the volume of a feed for a baby weighing 4.8Kg to receive 4
hourly feeds
150x4.8
= 120 ml per feed.
6
Or
200 x 4.8
= 160ml per feed
6
39. An infant (Max) is expected to regain his birth-weight after 2 weeks, then
gain 200g per week until 3 months of age; 150g per week for a further 3
months of age.
Assume 3 months = 13 weeks.
The volume of feed Max requires is calculated according to the formula:
Max requires approximately 115kcal/kg body weight per 24 hours.
The birth weight of baby Max is 2.9kg.
a) Calculate the volume of feed required if Max is to be fed every three hours.
Secondly
b) Calculate the expected weight of Max when aged 14 weeks
40. You may also have to calculate the energy requirements
If the baby requires approximately 115 kcal/kg body weight per 24 hours.
and the birth weight of baby Sam is 2.9kg.
What is the energy requirements?
Given that 1kcal = 4.2kJ, calculate the energy Sam receives in a day, when
she is 14 weeks old (to the nearest whole number)?
17
Another calculation midwives may need to do is the Body Mass
index.(BMI)
The most common measurement is BMI (kg/M²) = Weight(KG)
[Height(M)]²
Below 18.5
18.5 -24.9
25 - 29.9
30 & Above
Underweight
Normal
Overweight
Obese
41. Calculate the following BMI
Sarah is 1.6 m (height)and weighs 82kg =
42. Calculate the following BMI
Polly is 1.72m (height) and weight 72kg =
Insulin
These drugs are expressed in terms of units as a standard measurement.
There are no calculations involved in the administration of insulin either by
injection or devices such as pens. Insulin comes in units and all you have
to do is draw up the prescribed units or use the pen with the required dose.
Insulin syringes are calibrated as 100 units in 1ml and are available as 1ml
and 0.5 ml syringes. So if the dose is 30 units, you draw up to the 30 unit
mark on the syringe.
Heparin is also expressed in terms of units rather than weight.
The strengths available are:
1,000units/mL 1mL, 5mL, 10mL ampoules
5,000 units /ml 1mL.%mL ampoules
10,000 units /ml 1mL ampoules
25,000units/mL 1mL ampoules.
18
A strength of 25,000 units ml is also available for subcutaneous use as 0.2ml
ampoules containing 5,000 units.
Calculations are required depending on the dose prescribed and the mode
used to give it to the client. E.g. subcutaneous or intravenous.
43. You need to give an infusion of heparin containing 29,000 units over 24
hours. Assuming that the only strength you have available are 25,000
unit/ml and 5,000 units per ml, how much do you need to draw up for the
dose prescribed.?
You are advised to read the Nursing and Midwifery Council
Standards for Medicines Management (2008) before YOU start to give
any medicines. Standard 8 in particular
Also read the Midwives rules and standards (2004) rule 7.
Remember
Safe medication means giving the correct medication, to the right
person, in the right amount, at the right time and by the correct route
You need to ensure you familiarise yourself with administrations routes,
common abbreviations, and the pharmacy drug charts used in your Trust.
Other aspects such as trade names /brand names/ pharmaceutical forms/
clinical details/contraindications and interactions should be considered.
Pregnancy and lactation- clinical trials are mainly based on animal
studies and any observations in humans recorded.
Reference in the text
Lapham R Agar H (2003) Drug calculations for Nurses a step b step
approach 2nd edition. Hodder and Arnold London
Coben D Atere-Roberts E (2005) Calculations for Nursing and Health
care 2nd Edition Palgrave Macmillian Hampshire.
Or UWE
http://learntech.uwe.ac.uk/numeracy
19
Common midwifery drugs used in OSCE practice.
Syntometrine
Dosage : 1ml. - 5 units syntocinon
500mcg ergometrine
Route: Intramuscular
Action: Syntocinon – uterine contraction
Ergometrine – sustained contraction
45 minutes
Syntocinon
Dosage either
10 units Intramuscularly or
30 - 40 units /500mls Normal saline Intravenously
Rate: 125 mls/hour
Ergomentine
Dosage : 500mcg
Route: Intramuscular/intravenous
Action: Sustained contraction/living ligature
effect.
IM – 7 minutes
IV - 45 seconds
Only 2 doses of ergometrine can be given
Other drugs
Magnesium Sulphate:
ACTION: Relieves Cerebral Vasospasm
DOSE: IV route preferred: Loading dose 4g over 5-10 minutes followed by a
maintenance infusion of 1g/hr (continued at least 24 hours after the last
seizure).
Recurrent seizures should be treated by a further bolus of 2g (RCOG, 1999)
Side Effects: Magnesium Sulphate
Magnesium toxicity
Loss of deep tendon reflexes
Respiratory Depression
Respiratory Arrest
Clinical Observations Required:
20
Hourly measurements of the patellar reflex (if absent, withhold further doses
of Magnesium Sulphate until reflexes return)
ECG (BNF, 1996)
Respiratory rate
Oxygen saturation
Regular monitoring of serum levels should be considered in women with
oliguria (urine output < 100mls in 4 hours) as this drug is excreted by the
kidney
Monitor fetal heart rate continuously if not delivered
Respiratory Depression: Treat with
Calcium Gluconate 1g IV given over 10 minutes
Diazepam: Dose: 10 mgs IV
Hydralazine (5mgs iv repeated every 20 minutes to a MAXIMUM dose of
20mgs)
Labetolol (20 mgs iv can be titrated escalating to 40-80mgs every 10 minutes
to a maximum dose of 300mgs
(RCOG, 1999)
These drugs can cause fetal distress. If fetus undelivered continuous CTG is
advocated (RCOG, 1999)
Paracetamol
Lignocaine Hydrochloride 1%
Pethidine
Naloxone Hydrochloride
Vitamin K by injection and oral
Ranitidine
Human Anti D immunoglobulin
Ibrupofen
Ferrous sulphate
A number of these drugs come under either Patient group protocols or
Patient group directives. These will be discussed on your wards and
during the programme.
21
Answers to Practice Questions
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
14.
15.
16.
17.
18.
19.
20.
21.
22.
23.
24.
25.
500 micrograms
62.5 micrograms
250 micrograms
250 nanograms
62.5 nanograms
1500 nanograms
0.3 mgs
0.075 mgs
0.1875 mgs
250
300
225
0.6
0.2272
0.11
0.25
0.333
0.5
0.333
0.875
0.75
0.01
1310 mls
380 mls
1680 mls
26.
4000 micrograms = 4 mg
6mg
= 6000 micrograms
2 litres = 2000ml
0.24 micrograms = 240 nanograms
75 mg = 0.075grams
187.5 micrograms = 0.1875 mg
650 ml = 0.65 litres
0.25 micrograms = 250 nanograms
27.
Dose Prescribed (mg)
250
350
65
150
750
Volume Required (ml)
2.5
3.5
0.65
1.5
7.5
22
28.
Dose Prescribed (mg)
25
16
35
65
150
Volume Required (ml)
1.66
1.066
2.33
4.33
10
29.
30
31
32
33
5 mls
9 mls
0.6 mls
0.1 mls
125mls
34
a) Daily intake and output.
FLUID INTAKE (millilitres)
TIME
3rd March
4th March
5th March
08:00
09:00
10:00
11:00
12:00
13:00
14:00
15:00
16:00
17:00
18:00
19:00
300
300
250
DAY
TOTALS
20:00
21:00
22:00
23:00
00:00
01:00
02:00
03:00
04:00
05:00
06:00
b)What
07:00
FLUID OUTPUT (millilitres)
6th March 3rd March 4th March 5th March. 6th March
250
280
280
230
250
250
125
135
225
300
135
133
240
270
140
152
200
300
250
175
220
370
230
270
250
525
225
250
300
1645
925
920
1215
950
450
695
330
700
125
100
760
380
150
350
320
is Jane’s average daily fluid intake over these
400 4 days?
300=1270mls
345
NIGHT
TOTALS
0
100
125
150
850
630
670
725
24 HOUR
TOTALS
1645
1025
1045
1365
1800
1325
1370
1485
23
c) What is Jane’s average daily fluid output over these 4 days 1495ml
34
B)Average daily fluid intake = 1270mls
C) Average daily output. =1495ml
35 D ) 64mls
36 . Susan has regular epileptic seizures but these are reasonably controlled
through the use of medication. Currently she is prescribed Phenytoin in a
suspension which contains 15mg/2.5ml. The initial dose is worked out
according to body weight (3.5mg per kg daily).
a) If Susan is 86kg what would her initial daily dose be (to the nearest
10mg)? 300mg
Because Susan’s epilepsy is now generally well-controlled she is actually
prescribed 255 mg Phenytoin a day to be given in 2 equal doses.
B ) How many millilitres of suspension should be given in each dose?
21.25ml
37. Mrs James daily dose of drug A in grams is:
1.4g
38. Calculate the drop rate if the women requires 5% dextrose solution to be
given IV over 12 hours via a machine that has a drop rate of 20
= 13.89 drop rate.( Rounded up would be 14 drops per minute )
39.
a) Calculate the volume of feed required if Max is to be fed every three
hours.= 72.5ml
b) Calculate the expected weight of Max when aged 14 weeks= 5.25kgs
40. Calculate the energy requirements for Sam = 2.536 Kilojules
41. Sarah is 1.6 m and weighs 82kg = 32 BMI
42. Polly is 1.72m (height) and weighs 72kg = 24 BMI
43. Amount required 1XHeparin 25,000 unit /ml ampoule and 0.8ml of Heparin
from the 1X5,000 unit/ml and then add to the infusion.
24