Summary of Text rules. Systems Of Measurements UnitAbbreviationEquivalents gramg1 g = 1,000 mg...
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Transcript of Summary of Text rules. Systems Of Measurements UnitAbbreviationEquivalents gramg1 g = 1,000 mg...
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
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
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)
Converting Between Traditional and
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.
Converting Between Traditional and
International Time
Example 1 3:00 PM = 3:00 + 1200 = 1500Example 2 2212 = 2212 – 1200 = 10:12 PMAddition review questions p 94
Converting Between Traditional and
International Time
Convert 95˚ F to Celsius (First subtract 32 then divide the result by 1.8)
Celsius and Fahrenheit Scales
C = 95-32
1.8
C = 63
1.8
C = 35°
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
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
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
Used only once and is discardedDiscard any extra medication prior to injection
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
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
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
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
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
Full quantity contained in bottle or vial
Total number of tablets or other solids
Total fluid volume for liquids
Total Volume
Warnings or special alerts◦ExamplesRefrigerate at all timesKeep in a dry place
◦Manufacturer ◦Pharmacies
Label Alerts
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
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
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
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
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
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
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.
Reconstitution of Solutions
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
Reconstitution of Solutions
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)
Reconstitution of Solutions
Example 1 ⁄ 3 strength formula1 part concentrate formula (solute)
3 parts total solution3-1= 2 parts solvent (water)
Reconstitution of Solutions
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
Reconstitution of Solutions
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
Reconstitution of Solutions
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
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
Infusion Pump Rate for less than 1 hour
Order: ◦Ampicillin 500 mg IV in 50 mL D5NS to infuse over 30 min via infusion pump
Infusion Pump Rate for less than 1 hour
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
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