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Patrick Saintas 2007

• IntroductionThis Topic is part of the overall package on the safe administration of medicine and Fluid replacement therapy

• Aims Facilitate your understanding of the metric system in measuring the quantity of drugsBuild upon your familiarity with units of measurements Provide a number of examples and exercises to facilitate the development of skills in converting from one base unit to another

• Learning ObjectivesAfter working through this package, the user should be able to:-Explain the need for nurses to be conversant with the metric systemDescribe the need for a universal system of measurement such as the SI units in the prescription and administration of drugsUndertake the conversion of one base unit to another

• The Metric SystemSystem used for measuring the quantity of drugsUse in the UK and many other countries of the world for measurements in clinical and pharmaceutical practiceAlready familiar with this measuring system- the chief unit of weight in this system is the Kilogram

• The Problem/confusionUnits of measurements which meant nothing to any one elseNecessity of a uniform system1960 saw the adoption of the Systeme Internationale des Unites SI unitsSI units are simply metric units- The internationally agreed versions of the metric systemUse of SI ensured that all quantities expressed in metric units will be stated in the same manner in all disciplines

• Metric Systems FamiliarityAlready familiar with many SI unitsPause the presentation to make a list of some of the units you are familiar with.You may wish to have a look at this link to view a number of measurements used in real life http://www.thinkmetric.org.uk/index.htmlCheck the items from this link against those which you may have listed in your maths diary and journal.

• Units

• Multiple UnitsPrefixes such as Kilo, milli and micro are used to express large or very small quantities

A Kilo is equal to 1000 and is represented by the symbol K

A milli is 1divided by 1000 and is represented by the symbol m

A micro is 1 divided by 1000 000 and is represented in clinical setting by the letter mc or is written in full, e.g microgram

• Multiple Units (Contd)A unit can be expressed either by writing its name in full (e.g gram), giving the appropriate prefix if necessary (e.g milligram)OrBy putting the symbol for the prefix in front of the symbol for the basic unit.for example mgmilligram

• CautionCare is needed to ensure that the symbols are accurate and that capital letters and small letters are properly differentiated

e.g M is the symbol for mega which means a million = 1000000m is the symbol for milli =

• ApplicationDrugs Millilitre (mL) and Milligram (mg) have been used in metric quantities for some years Errors are most likely to occur with milligrams and micrograms- it is recommended that no abbreviation should be used when prescribing or labelling medicine- it should be written as microgram.

• ConclusionHope that you have found this package helpful as background information. Please do not forget to complete your maths' diary and your journalPlease have a go at the conversion exercises and quizHave a look at the Resources in the topic area of the course site

This Topic is part of the overall package on the safe administration of medicine and Fluid replacement therapy

The aims of this session are as follows:Facilitate your understanding of the metric system in measuring the quantity of drugsBuild upon your familiarity with base units of measurements such as grams, kilogramsProvide a number of examples and exercises to facilitate the development of skills in converting from one base unit to another

After working through this package, the user should be able to:-Explain the need for nurses to be conversant with the metric systemDescribe the need for a universal system of measurement such as the SI units in the prescription and administration of drugsUndertake the conversion of one base unit to another

System used for measuring the quantity of drugsThis system is used in the UK and many other countries of the world for measurements in clinical and pharmaceutical practice You are already familiar with this measuring system- the chief unit of weight in this system is the gram

Some countries still clung to units of measurement which were peculiar to that country and meant little to any one else- eg a yard does not mean any thing to a JapaneseIt was necessary to have a uniform system which everybody understandsIn 1960 at the Paris meeting of the general conference of weights and measures, it was suggested that the Systeme Internationale des unites or SI units should be adopted throughout the world. British Govt confirmed that the changes should be effective from 1975 SI units are simply metric units- The internationally agreed versions of the metric systemUse of SI ensured that all quantities expressed in metric units will be stated in the same manner in all disciplines

Already familiar with many SI unitsPause the presentation to make a list of some of the units you are familiar with. You may have already come across metres, kilogram and degree Celsius from the activities in your journal or maths diary

You may wish to have a look at this link to view a number of measurements in real life http://www.thinkmetric.org.uk/index.htmlCheck how many items that you have already referred to in your maths diary and journalThe Units for commonly occuring standard measurements are shown in the table. Pause the presentation and have a look at the symbol and the answer this question.

Why should you not add the symbol s to Kg?

Answer: because s is the symbol denoting time in second and a number of individuals commonly add s to kg when expressing kilograms in the plural. E.g. kgs this can be confusing. I should be written as KgPrefixes such as Kilo, milli and micro are used to express large or very small quantities

A Kilo is equal to 1000 and is represented by the symbol K

A milli is 1divided by 1000 and is represented by the symbol m

A micro is 1 divided by 1000 000 and is represented in clinical setting by the letter mc or is written in full, e.g microgram

A unit can be expressed either by writing its name in full (e.g gram), giving the appropriate prefix if necessary (e.g milligram)OrBy putting the symbol for the prefix in front of the symbol for the basic unit.for example mg

Care is needed to ensure that the symbols are accurate and that capital letters and small letters are properly differentiated e.g M is the symbol for mega which means a million = 1000000m is the symbol for milli =Drugs Millilitre (mL) and Milligram (mg) have been used in metric quantities for some years Errors are most likely to occur with milligrams and micrograms- it is recommended that no abbreviation should be used when prescribing or labelling medicine- it should be written as microgram. See that the becotide inhalers dosages are in Micrograms. Some Doctors will normally write mcg to denote microgram- be cautious when reading Prescription

Hope that you have found this package helpful as background information. Please do not forget to complete your maths' diary and your journalPlease have a go at the conversion exercises and quiz