Summary of Text rules. Systems Of Measurements UnitAbbreviationEquivalents gramg1 g = 1,000 mg milligrammg1 mg = 1,000 mcg = 0.001 g microgrammcg (or

Pickar Dosage Calculation

Summary of Text rules

Chapter 3Systems Of Measurements

Metric Measurements and Equivalents

Unit Abbreviation Equivalents

gram g 1 g = 1,000 mg

milligram mg 1 mg = 1,000 mcg = 0.001 g

microgram mcg (or µg) 1 mcg = 0.001 mg = 0.000001 g

kilogram kg 1 kg = 1,000 g

Weight

Metric Measurements and Equivalents

Unit Abbreviation

Equivalents

liter L (or ℓ) 1 L = 1,000 mL

milliliter mL (or mℓ) 1 mL = 0.001 L = 1 cc

cubic centimeter

cc 1 cc = 1 mL = 0.001 L

Volume

Household System of Measurement

Unit Abbreviation Equivalents

drop gtt

teaspoon t (or tsp) 5 mL

tablespoon T (or tbs) 1 T = 3 t

ounce (fluid) oz 2 T = 1 oz

ounce (weight) oz 1 lb = 16 oz

cup cup 1 cup = 8 oz or 240mL

pint pt 1 pt = 2 cups

quart qt 1 qt = 4 cups = 2 pt

Due to information from our clinical partners and the Board of Nursing the following rule was developed.

We will accept documentation in the form of Roman numerals, Arabic numbers, decimals as well as fractions.

Apothecary Notation

Conversions: Metric, Apothecary,

and Household Systems

Chapter 4

MULTIPLY to convert from a larger unit to a smaller unit, or move the decimal point to the right.

Metric Conversions

Example: 3 L = ? mLTHINK: Larger to Smaller: (×)Equivalent: 1 L = 1,000 mL3 L = 3 ×1,000 or 3.000 = 3,000 mL

Metric Conversions

DIVIDE to convert from a smaller unit to a larger unit, or move the decimal point to the left.

Metric Conversions

Example: 400 mg = ? GTHINK: Smaller to Larger: ()Equivalent: 1 g = 1,000 mg400 mg = 400 1,000 or 400. = 0.4 g

Metric Conversions

Shortcut Conversion

Rule

QE M

D

QuantityEquivalentMatching

Desired unknown thematches that

conversion

amount

Conversion Example The physician ordered 125 mcg of digoxin to be given daily. Digoxin was supplied in 0.25 mg scored tablets. How many tablet(s) should be administered?

0.25mg x 1000mcg/mg = 250 mcg

tablets0.5 tablet 1 mcg 250

mcg 125

1 in = 2.5 cm1 cup = 240 mL1 oz = 30 mL1kg = 2.2 lb

We will not be using the grain (gr) measurement in our math calculations.

Conversion Clarifications

40 kg = ? Lb 40 kg X 2.2lb/kg = 88 lb66lb = ? kg 66lb 2.2 kg/lb = 30 kgRemember you will round to tenths when needed. Example 5.23 will be rounded to 5.3

Conversion

40 cm = ? In 40 cm 2.5 cm/in =16 in32 in = ? cm 32 in x 2.5 cm/in = 80 cm

Conversion

Chapter 5Conversions

24-Hour Clock

AM Int’l. Time PM Int’l Time

12:00 midnight 2400 12:00 noon 1200

1:00 0100 1:00 1300

2:00 0200 2:00 1400

3:00 0300 3:00 1500

4:00 0400 4:00 1600

5:00 0500 5:00 1700

6:00 0600 6:00 1800

7:00 0700 7:00 1900

8:00 0800 8:00 2000

9:00 0900 9:00 2100

10:00 1000 10:00 2200

11:00 1100 11:00 2300

Traditional and 24-Hour Clock

Traditional time and international time are the same hours starting with 1:00 AM (0100) through 12:59 PM (1259).

Minutes after 12:00 AM (midnight) and before 1:00 AM are 0001 through 0059 in international time.

Converting Between Traditional and

International Time

Hours starting with 1:00 PM through 12:00 AM (midnight) are 12 h greater in international time (1300 through 2400)

International time is designated by a unique four-digit number (colon’s are not used)


International Time

Math Tip between the hours of 1:00 PM (1300) and 12:00 AM (2400), add 1200 to traditional time to find the equivalent international time; subtract 1200 from international time to convert to equivalent traditional time.


International Time

Example 1 3:00 PM = 3:00 + 1200 = 1500Example 2 2212 = 2212 – 1200 = 10:12 PMAddition review questions p 94


International Time

Celsius and Fahrenheit Scales

Convert between Fahrenheit and Celsius temperatures:

32C1.8F

1.8

32FC

Convert 95˚ F to Celsius (First subtract 32 then divide the result by 1.8)


C = 95-32

1.8

C = 63

1.8

C = 35°

Convert 35˚ C to Fahrenheit


F = 1.8 35+12

F = 63+12

F = 95°

Chapter 6 Equipment Used in Dosage Measurement

Medicine cup 1 fluid ounce or 30mL capacity for oral liquids.

Calibrated to measure teaspoons and tablespoons

Amounts less than 2.5 mL need to be measured in a smaller device, i.e. oral syringe

30 mL = 1 ounce 5 mL = 1 teaspoon15 mL = 1 tablespoon

Medicine Cup

Medicine Cups

Calibrated Dropper

Used to administer small quantities

Useful in medication of children and adults and adding small quantities to liquid

Dispense eye and ear medications

Calibrated Dropper

Pediatric Oral Devices

Calibrations read from top to the black ring of the suction plunger

Calibrated in milliliters for each tenth Maximum volume administered in any one site is 3mL

Larger volumes of medications can be delivered in divided doses or added to IV infusions or administered IV push, therefore, syringes with 5,6,10, and 12 mL may be used

3 mL Syringe

3 mL Syringe

Luerlock syringe hub

NeedleBarrel

Rubber plunger tip

Plunger

3 mL Safety Syringe

Used only once and is discardedDiscard any extra medication prior to injection

Prefilled Single Dose Syringe

Prefilled Single Dose Syringe

Also known as Tuberculin or TB syringe

Used to administer small dosesCalibrated in hundredths of a milliliter

Used to give dosages of less than 0.5 mL

1 mL Syringe

1 mL Syringe

Measurement and administration of units-100 insulin only

Do not use with any other medications

Syringe may be a standard units-100 or a Lo-dose units-100 for smaller doses

Units -100 Insulin Syringe

Units -100 Insulin Syringe

The needle is protected by a shield Safety syringes are used to protect from

injury

Safety Syringes

Safety Syringes

Safety Syringes

Needle’s gauge is it’s interior diameter. Lower the number the larger the diameter; 18-gauge needle is wider than a 22 gauge.

The gauge depends on the viscosity (thickness) of the medication as well as the site.

The viscous the solution and deeper injections require larger needles (lower gauge number)

Injection site (area of tissue to be reached) will determine the length to be used.

Needle Gauge and Length

TYPE AGE NEEDLE SIZE

GAUGE(G)

NEEDLE LENGTH

MAXIMUM INJECTION AMOUNT

LOCATION

IDIntradermal

All ages 25 to 26 G 1/4 to 5/8 0.1 mL Interior aspect of forearm

Subcut 1 to 12 months

23 to 27 G 5/8 0.5 mL Fatty tissue over lateral thigh muscle

Subcut 12 months to adult

23 to 27 G ½ to ¾5/8 most common

0.5 to 1mL

Fatty tissue over anterior lateral thigh muscle, triceps, or abdomen

IM Infant to child

22 to 25 G 5/8 to 1 inch

0.5 to 1 mL

Vastus Lateralis

IM Adult 21 to 25 G 1 to 1 ½ inches

2 to 3 mL 0.5 to 1 mL

VentrogluealDeltoid

Chapter 8Understanding Drug Labels

Brand, trade, proprietary Manufacturer’s name for a drug. It is usually the most prominent word on the drug label

GenericEstablished, nonproprietary name appears directly under the brand name. Sometimes it can be place inside

Drug Name

Brand Name- CarafateGeneric Name- Sucralfate

Brand and Generic Names

Dosage weight or amount of drug provided in a specific unit of measurement

20 mg/ 2mL

Dosage Strength

Structure and composition of drug◦Solid forms for oral use◦Injectable◦Suppositories◦Creams ◦Patches

Form

Oral Forms

Full quantity contained in bottle or vial

Total number of tablets or other solids

Total fluid volume for liquids

Total Volume

30 mL multiple dose vial

Identify Volume

Warnings or special alerts◦ExamplesRefrigerate at all timesKeep in a dry place

◦Manufacturer ◦Pharmacies

Label Alerts

Check prior to administrationDiscard or return to pharmacy if expired

Expiration Date

Important if drug is recalledQuickly identifies a particular group of medication packages

Lot or Control Numbers

Classifies drugs according to potential for use and abuse◦Schedule I – highest potential for abuse

◦Schedule V – lowest potential for abuse

Controlled Substance Schedule

ManufacturerNational Drug CodeBar CodeReview p 138 & 139

Other Parts of Label

Additional practice on page 142-148 Review set 21questions

Understanding Drug Labels

Chapter 10Oral Dosage Calculations

Step 1 Convert Be sure that all measurements are in the same system and all units are in the same size, converting when necessary Step 2 ThinkCarefully consider what is the reasonable amount to administer Step 3 Calculate Dosage

Dosage Calculations

Ordered: Flagyl 0.75 g p.o t.i.d You need to convert the 0.75 g to mg

prior to calculating amount that you will be administering

0.75 g = 750 mg

X(quanity) Q

(have) H

desired D

Step 3 Dosage Calculation

tablet1 x mg 500mg 750

Q H

D

Math Tips When solving dosage problems for drugs supplied in tablets or capsules, Q (quantity) is always 1 because the supply dosage is per 1 tablet or capsule. Therefore, Q = 1 tablet or capsule

The maximum number of tablets or capsules for a single dose is usually 3.

Dosage Calculation

Do not always rely on a formula.Always estimate what is a reasonable amount of the drug to be administered.

This helps to identify if the dosages calculated are reasonable and sound.

Remember

Parenteral Dosage of Drugs

Chapter 11

Routes of administration Intramuscular (IM)Subcutaneous (SC)◦Intradermal (ID)◦Intravenous (IV)

Parenteral

Maximum dosageAverage 150 lb adult = 3 mLMaximum for deltoid site is 2Children age 6-12 years = 2 mLChildren birth to age 5 years = 1 mL

Intramuscular

Parenteral dosagesRound amount to be administered to tenths if amount greater than 1 mL . Use a 3 mL syringe

Amounts less than 1 mL rounded to hundredths. Use a 1 mL syringe for all amounts less than 0.5 mL

Rounding Rule

Parenteral dosagesAmounts of 0.5 mL to 1 mL calculated in tenths can be accurately measured in either a 1 mL or a 3 mL syringe

Rule

Insulin LabelBrand Name Storage

Expiration Date

Type Generic NameSpecies

ManufacturerConcentration

Supply dosage of insulin is 100 units per mL

Abbreviated on label as U-100Syringe must also be U-100

Insulin

Accuracy is critical Nurses must understand and correctly interpret insulin order and label

The correct syringe must be selected

Insulin

Combination Insulin Dosage

40 unitsNPH

Units-100 insulin

12 unitsRegularUnits -100 insulin

Total insulin dosage = 52 units

Preparing Combination Insulin Dosage

1. Inject 30 units of air.

2. Inject 10 units

of air.

Preparing Combination Insulin Dosage

3. Withdraw 10 units

regular.

4. Withdraw 30 units

NPH for a total of 40 units.

Procedure for Preparing Combination Insulin Dosage

1)Inject 30 U air

2)Inject 10 U air

3)Withdraw 10 U Regular

4)Withdraw 30 U NPHFor a total of 40 U

Reconstitution of Solutions

Chapter 12

When a fraction expresses the strength of a solution, made from a liquid concentration

1. The numerator of the fraction is the number of parts of the solute.

2. The denominator of the fraction is the total number of parts of the solution.

3. The difference between the denominator(final solution) and the numerator (parts of solute) is the number of parts of solvent.


Solute- a concentrated or solid substance to be dissolved or diluted.

Solvent- is the diluent used to dissolve the solute

Solution- the resulting mixture of a solute plus a solvent



Example ¼ strength reconstituted OJ made from canned frozen concentrate

¼ strength =1 part frozen juice concentrate 4 parts total reconstituted OJ 1 part -OJ concentrate (solute, numerator) 4 parts- total reconstituted OJ ( solution,

denominator) 4-1 = 3 parts water (solvent)



Example 1 ⁄ 3 strength formula1 part concentrate formula (solute)

3 parts total solution3-1= 2 parts solvent (water)


Remember to convert all fluids to the same equivalent when necessary.

Example: Order Ensure ¼ strength 120mL for 3 feedings (Stock 4 fl oz can)

Step 1 convert fluid to same equivalent 4 fl oz x 30mL/fl oz = 120mL ensure concentrate


Step 2 calculate solute, solvent, and total solution 1 part solute(ensure) of 360 = 90 mL 4 parts solution ( solute and solvent) (3 feeding of 120 mL ¼ feeding = 120 x 3= 360 mL) 4-1= 3 parts solvent 270mL


Pediatric and Adult Weight Based Dosages

Chapter 14

Convert child’s weight from lb.'s to kg’s and round answer to tenths

Example 45lb ÷ 2.2 lb/kg= 20.45 rounded to 20.5 Example Convert 10 lb 12 oz to kg First convert ounces to lb 12 oz ÷16 oz/lb= 12/16 = ¾ lb= 0.75 lb 10.75 lb ÷ 2.2 lb/kg = 4.88 rounded to 4.9

Weight Based Dosages

Second step: multiply mg/kg by child’s weight in kg.

Example Order Morphine Sulfate 0.05 mg/kg per dose Childs weight 35.9 kg 0.05 mg/kg/dose x 35.9 kg = 1.79 mg/dose Rounded to 1.8 mg/dose

Weight Based Dosages

Intravenous Solutions, Equipment, and Calculations

Chapter 15

IV Sites Peripheral

◦ Rate of infusion should not exceed 200 mL in one hour

Central line◦ Accommodates larger concentrations and

volumes of fluid

Calculation IV Flow Rate for Infusion Pump

Regulate an IV volume by electronic infusion pump or controller calibrated in mL per hour

mL/hordered h Total

ordered mL Total

(rounded to a whole number)

Calculation of IV Flow Rate for Infusion Pump

Order reads: D5W 250 mL IV over the next two hours by infusion pump

Calculation of IV Flow Rate for Infusion Pump

Step 1: Think•Pump is set by the rate of mL per hour

•So, if 250 mL is to be infused in two hours, how much will be infused in one hour?

Calculate IV Flow Rate for Infusion Pump

• Step 2: Use the formula:

– Set pump at 125 mL per hour

– Set total volume to infuse at 250 mL

h 1

mL 125

h 2

mL 250

mL/hordered h Total

ordered mL Total

Infusion Pump Rate for less than 1 hour

(rounded to a whole number)

mL/hmin/h 60ordered min Total

ordered mL Total


Order: ◦Ampicillin 500 mg IV in 50 mL D5NS to infuse over 30 min via infusion pump


50mL X 60 min/h = 100 mL/h 30 min

Set infusion pump to infuse at 100 mL/h with an infusion volume of 50 mL

Calculation of IV Flow Rate for manual regulation: Drops per min

Step 1: Calculate infusion volume for 1h (Volume ordered ÷by number of hours to infuse) round this answer to a whole number

Step 2: V x Drop factor= qtt/min T

Drop Factors

Calculation of Drops per min

Physician orders:◦D5W IV at 125 mL per hour

Infusion set is calibrated for a drop factor of 10 drops per mL

Calculate IV flow rate in drops per min

Notice that the mL cancel out, leaving drops per min

Calculation of Drops per min

mL 1

gtt 10

min 60

mL 125gtt/mL 10

min 60

mL 125

gtt/min 820.6

1

• Use your watch to count drops and adjust roller clamp to deliver 21 drops per min

Calculation of Drops per min: Microdrip Drop Factor

Order: D5W NS IV at 50 mL per h Drop factor is 60 drops per mLNotice order, 50 mL per hour, is the same as the flow rate of 50 drops per min when drop factor is 60 drops per mL

Calculation of gtt per min: Microdrip Drop Factor

mL per gtt min 60

mL 60

50

50 drops per min

Documents

Summary of Text rules. Systems Of Measurements UnitAbbreviationEquivalents gramg1 g = 1,000 mg milligrammg1 mg = 1,000 mcg = 0.001 g microgrammcg (or