AKA: Factor-Label Method - PowerPoint Presentation

Slide1

AKA: Factor-Label Method

Dimensional Analysis Slide2

Objectives

To increase knowledge of Dimensional Analysis (DA) for calculating medication dosages

Demonstrate the application and usage of Dimensional Analysis (DA) during medication dosage calculation and medication administrationSlide3

Safety Support for DA?

The Quality and Safety Education for Nurses (QSEN) project goal is to minimize the risk of harm to patients through individual performance

(

Cronenwett

et al., 2007)

Teacher knowledge makes a substantial contribution to student achievement

(Ball & Bass, 2003)

A standardized approach to medication calculation can provide a solution to more than 1 in 6 medication errors

(

Lesar

,

Briceland

, & Stein, 1997)Slide4

Advantages of Using DA for Medication Calculations

DA is a

consistent

approach without memorizing formulas

One step equations: no need for multiple equations

No formulas needed

Can be used for all problems and medications calculations

Promotes

critical thinking

Use for simple or complex problems

Supports problem solving and critical thinking

Evidence

supports the use of DASlide5

Evidence for DA

Performance of the dimensional analysis method group as compared with the formula/ratio-and-proportion method group, indicated that the DA group performed statistically significantly higher

(

Serembus

, 2000)

.

DA used in chemistry, physics, and engineering

“While mistakes can still be made using any technique, DA does the best job of minimizing them. The only fault lies in the name. Perhaps the Math-Weenie No-Brainer Technique would be appropriate”

(Lee, 2006)

.Slide6

Conversions and Abbreviations to remember

1,000 mcg = 1 mg

gtt

= drop mcg = microgram

1,000 mg = 1 g

IM

= intramuscular

mg

=

milligram

1,000 g = 1

kg IV

= intravenous

g

= gram

1, 000 ml = 1 L

IVP

= intravenous push

ml

= milliliter

2.2

lbs

= 1

kg BID

= twice a day

L

= liter

1

oz

= 30 ml

TID

= three times a

day

oz

= ounce

gr1 = 60mg or 65 mg IVPB

= intravenous piggyback

1

tsp

= 5 ml

PO

= oral (by mouth) gr =

grain

1

Tbsp

= 15 ml

tsp

= teaspoon

Tbsp

= tablespoonSlide7

Dimensional Analysis

Five Steps for Dimensional Analysis

Identify the unit of measure desired in the calculation. Write the label for the answer on the right side of the equation

.

Place

the available information from the problem in fraction form on the left side of the equation. The abbreviation or unit matching the desired unit

on the left side, must

be placed in the numerator.

Enter conversion factors as fractions to work toward the desired label. (Equals over equals)

Cancel all labels that are in both the numerator and the denominator.

Do the math: multiply the numerators; multiply the denominators: then divide the numerator by the denominator.Slide8

Calculation for Pediatric Medications

Safe dosage needs to be completed prior to administering pediatric medications. The following steps should be taken to do this:

Pediatric medications are most commonly calculated based on body weight. The first step is to determine your patient’s weight in kg (most formulas are based on kg).

Safe dosage ranges are expressed in one of two ways:

mg/kg/day in specific divided doses (2 step procedure)

mg/kg/dose (1 step procedure)

Now you can calculate the patient’s safe dosage.Slide9

Sample problem #1

A 280 pound man weighs how many kg?

1.

=

kg

2. 1

kg

/2.2lb X 280lb = 280

kg

lb/2.2lb

3. 1

kg

/2.2

lb

X 280

lb

= 280kg/2.2

4. Answer = 127.2

kg

Answer sounds logicalSlide10

Sample problem #2

Order: Lasix (furosemide) 40mg PO daily

Available: tablets labeled 20mg

How many tablets will the nurse administer?Slide11

Sample problem #3

Administer D

5

LR at 75 ml/h. The drop factor is 10 gtt/ml.

Calculate the flow rate in gtt/min.Slide12

Sample Problem #4

Administer 1000 ml D

5

W in 6 hr. The drop factor is 15 gtts/ml.

Calculate the flow rate in gtts/min.Slide13

Sample Problem #5

Infuse 200ml of NSS in 2 hr. The drop factor is 20gtt/ml.

Calculate the flow rate in gtt/min.Slide14

Sample problem #6

Order: Gentamicin (garamycin) 55 mg IM q8h.

Available: Gentamicin (garamycin) 80 mg per 2 ml.

How many ml will the nurse administer for one dose?

How many ml will the nurse administer for one day?Slide15

Sample problem #7

Ampicillin 750 mg IV q4h.

Available: 2000mg per 5ml.

How many ml will the nurse administer for one dose?

How many ml will the nurse administer for one day?Slide16

Sample Problem #8

An IV of 500ml. NSS is to infuse at 60ml/hr. How long will the infusion take?

If the IV was started at 2000 (chronological time; military time), when would the infusion be complete (state in chronological time; military time).Slide17

Sample problem #9

Order: Gentamcin 50 mg IVPB q8h for a child weighing 40 lb.

The recommended dosage for a child is 6 to 7.5 mg/kg/day divided q8h.

Is the dosage ordered safe?Slide18

Sample Problem #10

Order: Phenobarbital 10 mg PO q12h is ordered for a child weighing 9 lb.

The recommended maintenance dose is 3 to 5mg/kg/day q 12h.

Is the dosage ordered safe?Slide19

Resources

Ball, D.L., & Bass, H. (2003). Toward a practice-based theory of mathematical knowledge for teaching. In Canadian mathematics education study group.

Proceedings of the 2007 annual meeting of the Canadian mathematics education study group.

Reston, VA: National Council of Teachers of Mathematics.

Cronenwett

, L., et al., (2007). Quality and safety education for nurses.

Nursing Outlook, 55

(3)122-131.

Lee, R.E. (2006). Medication math for the nursing student. Retrieved 6/12/2006 from:

http://alysion.org/dimention/analysis.htm

Lesar, T., Briceland, L., & Stein, D. (1997). Factors related to errors in medication prescribing.

Journal of the American Medical Association ,

277, 312-317.

Serembus

, J. (2000). Medication calculation ability of baccalaureate nursing students as a function of method of instruction.

Widener University (doctoral dissertation).