mathematics review and medication administration jeanelle f. jimenez rn, bsn, ccrn chapter 23 mosby...

Mathematics Review and

Medication Administration

Jeanelle F. Jimenez RN, BSN, CCRN

Chapter 23Chapter 23

Mosby items and derived items © 2011, 2006, 2003, 1999, 1995, 1991 by Mosby, Inc., an affiliate of Elsevier Inc.


Decimal FractionsDecimal Fractions

• Names of Decimal Places .00001 One hundred thousandths .0001 Ten thousandths .001 Thousandths .01 Hundredths .1 Tenths 1. Unit (whole number) 10 Tens 100 Hundreds 1000 Thousands 10,000 Ten thousands100,000 One hundred thousands


Decimal FractionsDecimal Fractions

• Names of Decimal Places (continued) A decimal point found left of a whole number means

that the number is a fraction of a whole number. A decimal point found after a number means that it is

a whole number. A number without a decimal point is understood to

have an “invisible” decimal point behind it.


Dosage CalculationsDosage Calculations

• 2 methods to use Ratio Proportion Method Formula Method


RatiosRatios

• Ratios show the relationship of one number or quantity to another number or quantity.

• Numbers of a ratio are separated by a colon.

• A ratio is also a fraction.

• The value of a ratio is not changed if both terms are multiplied or divided by the same number.

• When numbers are written in ratio, they must all be expressed in the same units.

• A fraction may be written as a ratio.


ProportionsProportions

• Proportion shows that the relationship between two ratios has equal value.

• Definitions Means: inner terms of the proportion Extremes: outer terms of the proportion

• Set up the left side of the proportion as the “known” side using information that is known or given.



• Set up the known side.

• Set up the unknown side. Use x for what you are trying to find.

• Set up the units in the same position on each side of the problem.

• Multiply the means.

• Multiply the extremes

• Solve for x (divide the number with the x into the number on the opposite side of the problem).

• Label the answer with the unit of measurement that accompanies the x in the problem.



• Review of Proportion Method Set up problems in the same order on both sides. Multiply the means; multiply the extremes. The number multiplied with the x is always that

number with the x to the right of it. Divide the number with the x into the number on the

other side of the problem. Label the problem by looking to see what unit of

measurement the x is with the proportion.


Dosage Calculations: Example #1Dosage Calculations: Example #1

The prescription is 1 mg Haldol IM (intramuscularly), and the medication is available in an ampule with a strength of 5 mg/1 mL. How many mL should be given?

SOLUTION: Set up a ratio

Known factors:

• Medication available = 5 mg (strength): Factor 1

• Volume = 1 mL: Factor 2

• Prescribed dosage = 1 mg: Factor 3

• Volume (mL) needed to give = X mL: Unknown


Dosage Calculations: Example #1 contd.Dosage Calculations: Example #1 contd.

SOLUTION, cont.

• Remember: Units of measure must cancel properly during calculations (see equation below). Set up units in the same position on each side of the

double colon:•5 mg is to 1 mL as 1 mg is to X mL


Dosage Calculations Example #2Dosage Calculations Example #2

The prescription of Penicillin G (oral tablets) is for 375 mg. Tablets are supplied in 250 mg scored (able to be divided in half) tablets. How many tablets should be given?


• 250 mg is to 1 tablet as 375 mg is to X tablets

• 250 mg: 1 tablet::375 mg: X tablets


Dosage Calculations #2 contd.Dosage Calculations #2 contd.

SOLUTION: cont.

• Multiply means: 375 mg × 1 tablet = 375 mg tablet 375 mg tablet ÷ 250 = X tablets Therefore, X = 1.5 tablets

Answer: The nurse would give 1.5 tablets. One scored tablet would need to be split in half


Dosage Calculations Example #3Dosage Calculations Example #3

The prescription is 75 mg Trazodone. The medication is provided in 150 mg scored tablets. How many tablet(s) are needed?


• 150 mg is to 1 tablet as 75 mg is to X tablets

• 150 mg: 1 tablet::75 mg: X tablet


Dosage Calculations Example #3 contd.Dosage Calculations Example #3 contd.

SOLUTION, cont.

• Multiply means: 75 mg × 1 tablet = 75 mg tablets 75 mg tablet ÷ 150 = X tablets Therefore, 0.5 = X tablets

Answer: The nurse would give 0.5 tablet (½ tablet).

• Note: If the dosage for tablets does not come out exactly, the prescribed dosage cannot be given.


Formula Method Formula Method

D/H x Q = amount to give

D = Desired dose (MD order)

H = What is available on hand

Q = Quantity (pill, tablet, ml, etc)


Significant FiguresSignificant Figures

• Numbers that have practical meaning or dosages that can be measured

• For example Dosage prescribed is 1.325 mL

• When measured with a syringe that has markings of 1.3 mL, 1.4 mL, and 1.5 mL, last two numbers (the “25”) cannot be measured

• Amount given is 1.3 mL, because this amount is closer to the prescribed dosage than 1.4 mL

• The dosage that can be measured, 1.3 mL, is the significant figure.


Significant Figures contd.Significant Figures contd.

• When rounding Dosage is rounded to the closest amount

• Using the example Values ranging from 1.301 to 1.349 are rounded down to

1.3 Values from 1.350 to 1.399 are rounded up to 1.4


The Metric SystemThe Metric System

• The metric system is based on the decimal system.

• The decimal system uses the divisions and multiples of a unit, which is always in ratios of tens.

• The metric system uses the following units: liter (L) = volume (amount) of fluids gram (g) = weight of solids meter (m) = measure of length



• Smaller units of the system are designated by the following prefixes: deci = 0.1 of the unit (liter, gram, meter); tenths centi = 0.01 of the unit; hundredths milli = 0.001 of the unit; thousandths

• Larger units of the system are designated by the following prefixes: deka = 10 times the unit (liter, gram, meter) hecto = 100 times the unit kilo = 1000 times the unit



• Units of Weight 1 gram (g) = 1000 milligrams (mg) 0.001 gram (g) = 1 milligram (mg) 1 kilogram (kg) = 1000 grams (g) 0.001 kilogram (kg) = 1 gram (g)

• Units of Volume 1 liter (L) = 1000 milliliters (mL) 0.001 liter (L) = 1 milliliter (mL) 1 milliliter (mL) = 1 cubic centimeter (cc)



• Approximate Equivalents of the Metric System and the Apothecary System Volume

• 1 milliliter (mL) = 15 or 16 minims

• 4 or 5 milliliters (mL) = 1 fluid dram

• 30 milliliters (mL) = 1 fluid ounce

• 500 milliliters (mL) = 1 pint

• 1000 milliliters (mL) = 1 quart



• Approximate Equivalents of the Metric System and the Apothecary System (continued) Weight

• 60 milligrams (mg) = 1 grain (gr)

• 1000 milligrams (mg) = 15 grains

• 4 grams (g or gm) = 1 dram

• 30 grams (g) = 1 ounce

• 0.45 kilogram (kg) = 1 pound (lb.)

• 1 kilogram (kg) = 2.2 pounds (lbs.)



• Metric Measurements of Length The basic unit of length is the meter. The meter is equal to 39.37 inches. 0.001 meter = 1 millimeter (mm) 0.01 meter = 1 centimeter (cm) 0.1 meter = 1 decimeter (dm) 10 meters = 1 decameter (dam) 100 meters = 1 hectometer (hm) 1000 meters = 1 kilometer (km)



• Metric Measurements of Length Most frequently used equivalents

• 1 meter (m) = 1000 millimeters (mm)

• 0.001 meter (m) = 1 millimeter (mm)

• 1 meter (m) = 100 centimeters (cm)

• 1 centimeter (cm) = 10 millimeters (mm)

• 1 millimeter (mm) = 0.1 centimeter (cm)


Pediatric ConsiderationsPediatric Considerations

• Young’s Rule A method for the calculation of the appropriate dose of

a drug for a child 2 years of age or older; applies to children up to the age of 12

Age of child _

(Age of child + 12) Average adult dose = Child’s dose



• Clark’s Rule A method of calculating the approximate pediatric

dosage of a drug for a child

Weight of child (lbs.)

150 Average adult dose

= Child’s dose



• Fried’s Rule This rule is used for infants younger than 2 years of

age.

Age in months

150 Average adult dose = Child’s dose



• Estimating Body Surface Area in Children Body surface area is defined as the total area

exposed to the outside environment. Use body surface area scale to find the correct

surface area (SA).

SA (m2)

1.73 m2 Adult dose = Child’s dose


PharmacologyPharmacology

• This is the study of drugs and their action on the living body.

• Substances derived from plants and animals, from vitamins and minerals, and from synthetic sources can be used as drugs in the treatment and prevention of disease.

• The action of any drug on the body is a complicated process.



• Drug Dosage The dosage is the amount of a drug prescribed for the

patient by the physician. A dose of medicine refers to a single prescribed

amount of drug given at one time. Nurses must become familiar with therapeutic

dosages of frequently used drugs to confidently administer dosages of medication to each patient.



• Drug Actions and Interactions Two general types

• Local: Affect only the area where the drug is placed

• Systemic: Affect the entire body Drug interaction: One drug alters another drug Potentiation: One drug increases the action or effect

of another drug Incompatibility: Drugs that do not combine chemically

with other drugs Antagonist: Drug that will block the action of another

drug


• An idiosyncratic response to a drug is an individual’s unique hypersensitivity to a particular drug.

• A reduced response to a drug is called tolerance.

• An adverse drug reaction is a harmful, unintended reaction to a drug administered at a normal dosage.

• Contraindications are conditions under which the drug should not be given.

• Interactions are modifications of the effect of a drug when administered with another drug.




• Factors that may affect how patients respond to medication: Age Weight Physical health Psychological status Environmental temperature Gender Amount of food in the stomach Dosage forms


Medication OrdersMedication Orders

• The nurse is ethically and legally responsible for ensuring that the patient receives the correct medication ordered by the physician.

• Medication orders should include the following: Patient's name Date and time of the order Name of the drug Dosage of the drug Route of administration Time or frequency drug is given Signature of the physician Any special instructions



• Controlled Substances Opioids, barbiturates, and other controlled drugs that

have a high possibility for abuse or addiction are double-locked.

“Narcotic keys” are kept by designated nurses per shift.

Each controlled drug used is logged into the narcotic log book.

At the end of each shift, controlled drugs are carefully counted by a nurse from the outgoing shift and a nurse from the incoming shift.

Always have a witness to the “wasting” of a controlled substance.



• Types of Orders Standing orders

• Already written by a physician for all patients on a particular unit or area

• Carried out without having to call the physician Verbal orders

• May be given in the presence of an LPN/LVN or an RN directly or over the telephone

• Should be written on the chart and signed by the physician as soon as possible


Medication AdministrationMedication Administration

• Six Rights Right medication Right dose Right time Right route Right patient Right documentation



• Important Considerations of Medication Administration If you did not pour it, do not give it. If you gave it, chart it. Do not chart for someone else or have someone else

chart for you. Do not transport or accept a container that is not

labeled. Do not put down an unlabeled syringe. If given a verbal order, repeat it to the physician. If you make an error, report it immediately.



• Important Considerations of Medication Administration (continued) Never leave a medication with a patient or family

member. Watch the patient take it and swallow it. Always return to assess the patient’s response. Chart as soon as possible after giving medication. If a patient refuses medication, do not force it; chart

“Refused medication because of. . . .” If you elect to omit a dose based on your nursing

judgment, let another nurse help make the decision. If medication is not given, document “Dose omitted because. . . .” Report to the physician.


Routes of AdministrationRoutes of Administration

• Enteral Via the GI tract

• Powders

• Pills

• Tablets

• Liquids or suspensions

• Suppositories



• Percutaneous Through the skin or mucous membranes

• Topical

• Instillation

• Inhalation



• Parenteral Methods other than the GI tract; needle route

• Ampules

• Vials

• Intramuscular

• Subcutaneous

• Intradermal

• Intravenous


Enteral AdministrationEnteral Administration

• Preparation of Tablets, Pills, and Capsules These preparations enter the GI tract and are

absorbed more slowly into the blood stream than via any other route.

The slow absorption rate makes the PO (by mouth) route relatively safe.

Some PO medications are irritating to the patient’s GI tract, and larger tablets may be difficult for some patients to swallow.


Skill 23-1: Step 5Skill 23-1: Step 5

Administering tablets, pills, and capsules.

(From Potter, P.A., Perry, A.G. [2005]. Fundamentals of nursing. [6th ed.]. St. Louis: Mosby.)



• Preparation of Liquid Medications Liquid medications are often given to children; to

patients who cannot swallow tablets, pills, or capsules; and to geriatric patients.

Medications may be given PO or via a nasogastric, gastrostomy, or jejunostomy tube.

Liquids must not be given to unconscious patients because of the possibility of aspirating.

Some liquid medications are not to be followed by water, and some may stain the teeth.



Administering liquid medications.




• Tubal Medications Nasogastric (NG) tubes are used to administer liquid

medications to unconscious patients, dysphagic patients, and those who are too ill to eat.

Many medications come in liquid form; if they do not, solid tablets may be pulverized in a mortar and pestle, and capsules can be opened.

Not all tablets are safe to use when crushed, and not all capsules are safe to use when opened.


Skill 23-3: Step 13aSkill 23-3: Step 13a

Administering tubal medications.



Administering tubal medications.



• Suppositories Cone-shaped, egg-shaped, or spindle-shaped

medication made for insertion into the rectum or vagina

Dissolves at body temperature and absorbed directly into the bloodstream

Useful for infants, patients who cannot take oral preparations, and patients with nausea and vomiting

Stored in cool place so they do not melt


Percutaneous AdministrationPercutaneous Administration

• With these routes, medications are absorbed through the skin or the mucous membranes.

• Most produce a local action, but some produce a systemic action.

• Drugs include topical applications, instillations, and inhalations and ointments, creams, powders, lotions, and transdermal patches.

• Absorption is rapid but of short duration.



• Ointments An oil-based semisolid medication; may be applied to

the skin or a mucous membrane

• Creams Semisolid, nongreasy emulsions that contain

medication for external application

• Lotions Aqueous preparations that are used as soothing

agents that relieve pruritus, protect the skin, cleanse the skin, or act as astringents



• Transdermal Patches (Topical Disk) Adhesive-backed medicated patches applied to the

skin provide sustained, continuous release of medication over several hours or days.

• Eyedrops and Eye Ointments Care should be taken to keep all ophthalmic

preparations sterile by not touching the dropper or the tube to the eye.

• Eardrops Containers of solutions to be used as eardrops will be

labeled “otic.” They must be at room temperature when applied.


Figure 23-4Figure 23-4

A variety of medications are available as transdermal patches.

(From Elkin, M.K., Perry, A.G., Potter, P.A. [2004]. Nursing interventions and clinical skills. [3rd ed.]. St. Louis: Mosby.)



• Nosedrops Nosedrops are for individual use only.

• Nasal Sprays Sprays absorbed quickly; less medication is used and

wasted when administered in this manner.

• Inhalation Drugs may be absorbed through the mucous

membranes of the respiratory tract. Inhalation produces a relatively limited effect or a

systemic effect. This method is actively used by respiratory therapy

and anesthesiologists.



• Sublingual Administration Drug is administered by placing it beneath the tongue

until it dissolves. Drug may be a tablet or liquid squeezed out of a

capsule. It is rapidly absorbed into the bloodstream.

• Buccal Administration A tablet is placed between the cheek and teeth, or

between the cheek and the gums. Absorption into the capillaries of the mucous

membranes of the cheek gives rapid onset of the drug’s active ingredient.


Parenteral AdministrationParenteral Administration

• Equipment Syringes

• Syringe consists of a barrel, a plunger, and a tip.

• Outside of the barrel is calibrated in milliliters, minims, insulin units, and heparin units.

• Types Tuberculin syringe Insulin syringe Three-milliliter syringe Safety-Lok syringes Disposable injection units



Parts of a syringe.




Tuberculin syringe calibration.

(From Clayton, B.D., Stock, Y.N. [2004]. Basic pharmacology for nurses. [13th ed.]. St. Louis: Mosby.)



Calibration of U100 insulin syringe.




Reading the calibrations of a 3-mL syringe.



Safety-Glide syringe.



Parts of a needle.




• Equipment (continued) Needles

• Parts are the hub, shaft, and beveled tip.

• Opening at the needle’s beveled tip is the lumen.

• Size of the diameter of the inside of the needle’s shaft determines the gauge of the needle; the smaller the gauge, the larger the diameter.

• Needle gauge selection is based on the viscosity of the medication.



• Equipment (continued) Needle length

• Selected based on the depth of the tissue into which the medication is to be injected

• Intradermal: 3/8 to 5/8 inch

• Subcutaneous: 5/8 to 1/2 inch

• Intramuscular: 1 to 1 1/2 inch Intravenous needles

• Butterfly (scalp needle)

• Over-the-needle catheter (Angiocath, Jelco)



Needle length and gauge.




• Equipment Needleless devices

• Devices are designed with a sheath or guard that covers the needle after it is withdrawn from the skin.

• Intravenous catheters have been designed with blunt-edged cannulas, valves, or needle guards to minimize injuries.

• IV tubing with recessed and shielded needle connectors has been designed, further reducing needlesticks.



• Intramuscular Injections Involves inserting a needle into the muscle tissue to

administer medication Site selection

• Gluteal sites

• Vastus lateralis muscle

• Rectus femoris muscle

• Deltoid muscle Z-track method

• Used to inject medications that are irritating to the tissues


Figure 23-15, CFigure 23-15, C

Locating IM injection for ventrogluteal site.

(C, from Elkin, M.K., Perry, A.G., Potter, P.A. [2004]. Nursing interventions and clinical skills. [3rd ed.]. St. Louis: Mosby.)



Giving IM injection in vastus lateralis site on adult.




Rectus femoris muscle. A, Child/infant. B, Adult.




Giving IM injection in deltoid site.




A, Z-track method. B, Using an air lock. C, Administering IM injection

by airlock technique.




• Intradermal Injections Introduction of a hypodermic needle into the dermis

for the purpose of instilling a substance such as a serum, vaccine, or skin test agent

Not aspirated Small volumes (0.1 mL) injected to form a small

bubblelike wheal just under the skin Used for allergy sensitivity tests, TB screening, and

local anesthetics A tuberculin syringe used with a 25-gauge, 3/8- to

5/8-inch needle



Angles of insertion for intramuscular (90°), subcutaneous (45°), and intradermal (15°).




• Subcutaneous Injections Injections made into the loose connective tissue

between the dermis and the muscle layer Drug absorption slower than with IM injections Given at a 45-degree angle if the patient is thin or at a

90-degree angle if the patient has ample subcutaneous tissue

Usual needle length is 1/2 to 5/8 inch and 25 gauge Used to administer insulin and heparin



Subcutaneous injection. Angle and needle length depend on the

thickness of skinfold.




• Intravenous Therapy Provide fluid and electrolyte maintenance, restoration,

and replacement Administer medication and nutritional feedings Administer blood and blood products Administer chemotherapy to cancer patients Administer patient-controlled analgesics Keep a vein open for quick access



• Methods of Intravenous Administration IV push Intermittent venous access device Intermittent infusion (or piggyback) Continuous infusion Electronic pumps and controllers Patient-controlled analgesia Volumetric chambers



PCA infusion pump.




Volumetric chamber.



• Nursing Responsibility The nurse must ensure that fluid of the ordered type

and amount is started and that the fluid is regulated to infuse over the period ordered.

To find the drops per minute (the drip rate), you must know which type of IV tubing will be used with the infusion and obtain the drip factor for the tubing to be used.



• Nursing Responsibility (continued) Monitor intravenous therapy

• Check the infusion and the IV needle site at least every hour.

Flow of fluid IV site: erythema, wetness, and edema Phlebitis: inflamed vein Infiltration: fluid passes into the tissues

• Assess for chills, fever, headache, nausea, vomiting, anxiousness, and dyspnea.



• Nursing Responsibility (continued) Assess for anaphylactic shock

• Respiratory distress

• Skin reactions

• Signs of circulatory collapse

• GI signs and symptoms

• Change in mental status Requires immediate intervention.


Nursing ProcessNursing Process

• Nursing Diagnoses Anxiety Health-seeking behaviors Injury, risk for Knowledge deficient Mobility, impaired Noncompliance: drug regimen Sensory/perception, disturbed

mathematics review and medication administration jeanelle f. jimenez rn, bsn, ccrn chapter 23 mosby...

Documents

mosby items

derived items

affiliate of elsevier

proportions proportion

proportion extremes

invisible decimal point

ratios ratios

unit of measurement