Base Hospital2003

Fall Recerts.

Medical Mathand Drug Calculations

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Milligrams

Milligrams

Milligrams

Milligrams

Milligrams

Milliliters

Milliliters

Milliliters

Milliliters

MillilitersKilograms

Kilograms

Kilograms

Kilograms

Kilograms

Kilograms

mg/kg/min

mg/kg/min

mg/kg/min

mg/kg/min

mg/kg/min

ml/cc

ml/cc

ml/cc

ml/cc

ml/cc

ml/cc

gtts/min

gtts/min

gtts/min

gtts/min

gtts/min

gtts/min

mg

mg

mg

mg

mg

mgMaking Sence Making Sence of of

Medical MathMedical Math

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Pre/Post Course Math

• Overall well done

• Some problems were found in the Precourse– Paramedics did not show their work,

therefore it was hard to determine the problem.

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•Calculators and medication tables are more than welcome, only if you intend on using them in your practice.

•You are encouraged to use the formulas supplied. If you have your own method and it works for you, do it your way.

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Where will I apply medical math??

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WANT

---------- = AMOUNT TO ADMINISTER

HAVE

HOW MUCH TO ADMINISTER

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WANT

• Protocols I.e. 0.3mg Epi. 1:1,000 SC

• Verbal Orders by patch phone

• Written Orders on Patient chart

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HAVE

• Concentration of the Drug– Nitro, Salbutamol, Glucagon, Lidocaine, etc.

• Contents of the IV Bag

• Amount in a given Ampoule or Vial

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Weight vs. Volume

REMEMBERWeight and Volume

are not the same thing

Weight is the amount of a drug -5.0mg of Ventolin

Volume is the amount of fluid the drug is dissolved in - 2.5 ml nebule

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Have = ConcentrationHave = Concentration

Concentration =Concentration =

VolumeVolume

WeightWeight

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Concentration

• mol/L• G/L• G% or %• mg%• Eq/L• m/Eq/L• mg/ml• mcg/ml

• moles per litre• grams per litre• grams/100mL• mg per 100 mL• equivalents/ L• milliequivalents per litre• milligrams/millilitre• micrograms/millilitre

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ConcentrationConcentration Reduce the Volume to 1 ml

which will make the math easier

100 mg in 20 ml =100 mg in 20 ml =

250 mg in 100 ml =250 mg in 100 ml =

60 mg in 15 ml =60 mg in 15 ml =

5 mg/ml5 mg/ml

2.5 mg/ml2.5 mg/ml

4 mg/ml4 mg/ml

mg/mlmg/ml

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= Amount to Administer (ml)= Amount to Administer (ml)ConcentrationConcentration

Amount OrderedAmount Ordered

5 mg/ml5 mg/ml

5 mg/2.5ml 5 mg/2.5ml 5mg/2ml 5mg/2ml

50 mg50 mg= = 10 ml10 ml

1 mg/ml 1 mg/ml

0.3 mg0.3 mg= = 0.0.3 ml3 ml

0.3 mg0.3 mg= = 0.120.12 ml ml

1.25 mg1.25 mg = = 0.6250.625 ml ml

Injection - mlInjection - ml

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= Amount to Administer = Amount to Administer (ml/min)(ml/min)ConcentrationConcentration

Amount OrderedAmount Ordered

200 mcg/ml200 mcg/ml

10 mg/ml 10 mg/ml 5 mg/ml 5 mg/ml

20 mcg/min20 mcg/min= = 0.1 ml/min0.1 ml/min

15 mg/min15 mg/min= = 3 ml/min3 ml/min

3 mg/min3 mg/min= = 0.30.3 ml/min ml/min

Infusion - ml/minInfusion - ml/min

==1 mcg/min1 mcg/min

10 mcg/ml10 mcg/ml

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== Amount to Administer Amount to Administer (gtt/min)(gtt/min)ConcentrationConcentration

Amount OrderedAmount Ordered

200 mcg/ml200 mcg/ml

20 mcg/min20 mcg/min = = 6 gtt/min6 gtt/min

Infusion gtt/minInfusion gtt/min

X drip factorX drip factor

x x 60 gtt/ml 60 gtt/ml = = 0.0.1ml/min1ml/min

15 mg/min15 mg/min

5 mg/ml 5 mg/ml = = 180gtt/min180gtt/min

3 mg/min3 mg/min

10 mg/ml 10 mg/ml = = 18gtt18gtt/min/min

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=Amount to administer =Amount to administer (ml/min)(ml/min)ConcentrationConcentration

Amount OrderedAmount Ordered

800 mcg/ml800 mcg/ml

10 mcg/kg/min10 mcg/kg/min= = 1ml / min1ml / min

If drop/ minute are If drop/ minute are required multiply required multiply

by drop factorby drop factor = 60 gtt/min= 60 gtt/min

Weight Based InfusionWeight Based Infusion

x Weight x Weight FactorFactor

x 80 kgx 80 kg

x 60 gtt/mlx 60 gtt/ml

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IV concepts

Two concepts:

1. Flow rate: the rate at which IV fluid is given.

2. The drip factor: the number of drops per mL determined by the administration set.

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Infusion = ml/hr

Calculate the drip rate when thePhysician Orders - 400 ml/hr

using a 10 gtts/ml drip set

400 ml/hr x 10 gtts/ml

4000 gtts/hr ÷ 60 min/hr

66.67 gtts/min ÷ 60 sec/min

= 1 gtt/sec

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REMEMBER

WANT

---------- = AMOUNT TO GIVE

HAVE

• The WANT may get more complicated involving time or patient weight.

• The HAVE is in your possession and may change in concentration depending on service supplies.

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Questions?