The Metric System

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• metric system

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Introduction

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

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Aims

• Facilitate your understanding of the metric
  system in measuring the quantity of drugs
• Build 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

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Learning Objectives

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

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The Metric System

• System used for measuring the quantity of drugs
• Use in the UK and many other countries of the
  world for measurements in clinical and
  pharmaceutical practice
• Already familiar with this measuring system- the
  chief unit of weight in this system is the
  Kilogram

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The Problem/confusion

• Units of measurements which meant nothing to any
  one else
• Necessity of a uniform system
• 1960 saw the adoption of the Systeme
  Internationale des Unites SI units
• SI units are simply metric units- The
  internationally agreed versions of the metric
  system
• Use of SI ensured that all quantities expressed
  in metric units will be stated in the same manner
  in all disciplines

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Metric Systems Familiarity

• Already familiar with many SI units
• Pause 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.html
• Check the items from this link against those
  which you may have listed in your maths diary
  and journal.

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Units
Quantity Unit Symbol
Length Metre m
Mass/Weight Kilogram Kg
Time Second s
Temperature Degree Celsius oc
Volume Litre L
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Multiple Units

• Prefixes 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

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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)
• Or
• By putting the symbol for the prefix in front of
  the symbol for the basic unit.
• for example mg

milli
gram
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Caution

• 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 1000000
• m is the symbol for milli

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Application

• 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.

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Conclusion

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