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)ConcentrationConcentrationAmount 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/ml10 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/hrCalculate the drip rate when the
Physician Orders - 400 ml/hr using a 10 gtts/ml drip set
400 ml/hr x 10 gtts/ml4000 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?