Successfully reported this slideshow.
Upcoming SlideShare
×

# Dosage Calculation Using Dimensional Ana

10,658 views

Published on

• Full Name
Comment goes here.

Are you sure you want to Yes No
• Be the first to comment

### Dosage Calculation Using Dimensional Ana

1. 1. Calculate with Confidence 5 th edition Gray Morris Mosby items and derived items © 2010 by Mosby, Inc., an affiliate of Elsevier Inc.
2. 2. Dosage Calculation Using the Dimensional Analysis Method Unit Three: Chapter 16 Mosby items and derived items © 2010 by Mosby, Inc., an affiliate of Elsevier Inc.
3. 3. Dosage Calculation Using Dimensional Analysis Method: Objectives <ul><li>After reviewing this chapter, you should be </li></ul><ul><li>able to: </li></ul><ul><ul><li>Define dimensional analysis </li></ul></ul><ul><ul><li>Implement unit cancellation in dimensional analysis </li></ul></ul><ul><ul><li>Perform conversions using dimensional analysis </li></ul></ul><ul><ul><li>Use dimensional analysis to calculate dosages </li></ul></ul>
4. 4. Background: Dimensional Analysis <ul><li>Fancy name—simple technique </li></ul><ul><li>Used to manipulate units in a calculation </li></ul><ul><li>Involves cancellation of unwanted units </li></ul><ul><li>Eliminates need to memorize formulas </li></ul><ul><li>Also known as the factor-label method or the unit factor method </li></ul><ul><li>Only one equation is used </li></ul>
5. 5. Performing Conversions Using Dimensional Analysis <ul><li>Conversions can be made within process of calculation rather than in advance </li></ul><ul><li>Equivalents or conversion factors are expressed as fractions written in one of two ways without changing meaning or value—e.g., CF: 1 kg = 1,000 g is the same as 1 kg/ 1,000 g or 1,000 g/ 1 kg </li></ul>
6. 6. Making Conversions Using Dimensional Analysis <ul><li>Identify desired unit </li></ul><ul><li>Identify equivalent needed </li></ul><ul><li>Write equivalent in fraction format with desired unit in numerator as first part of equation </li></ul><ul><li>Label all factors in equation, with x being what you desire to have in the end </li></ul>
7. 7. Making Conversions Using Dimensional Analysis (cont’d) <ul><li>Identify unwanted or undesired units and cancel, then reduce to lowest terms </li></ul><ul><li>Must be able to eliminate all labels except for answer label—if not, recheck </li></ul><ul><li>Perform mathematical process </li></ul><ul><li>Note: it is key to have the </li></ul><ul><li>equivalent set up correctly! </li></ul>
8. 8. Making Conversions Using Dimensional Analysis (cont’d) <ul><li>Example: 1.5 g = _______ mg </li></ul><ul><li>The desired unit is mg </li></ul><ul><li>Equivalent: 1,000 mg = 1 g </li></ul><ul><li>Write equivalent—keep mg in numerator (allows cancellation of unwanted unit, g) </li></ul><ul><li>Write equivalent as fraction, add multiplication sign </li></ul><ul><li>Perform calculation </li></ul>
9. 10. Dosage Calculation Using Dimensional Analysis <ul><li>Identify unit of measure (caps, mL, tabs) and place x on left with appropriate unit </li></ul><ul><li>On right, place available information as a fraction — information matching the x unit will be placed in the numerator </li></ul><ul><li>Enter additional factors — set up so unit of numerator matches preceding denominator </li></ul><ul><li>Cancel out like units — remaining unit should match the unit for x — then calculate </li></ul>
10. 11. Dosage Calculation Using Dimensional Analysis (cont) <ul><li>Example: Order is Lasix 40 mg p.o. daily </li></ul><ul><li>Available: 20 mg tablets </li></ul><ul><li>Place desired unit of measure on left and label as x </li></ul><ul><li>x = tab </li></ul>
11. 12. Dosage Calculation Using Dimensional Analysis (cont’d) <ul><li>Example: Order is Lasix 40 mg p.o. daily </li></ul><ul><li>Available: 20 mg tablets </li></ul><ul><li>Place the info in problem on right in fraction format—matching desired unit in numerator </li></ul>
12. 13. Dosage Calculation Using Dimensional Analysis (cont’d) <ul><li>Example: Order is Lasix 40 mg p.o. daily </li></ul><ul><li>Available: 20 mg tablets </li></ul><ul><li>Enter additional info (e.g., what is ordered), matching unit in numerator with preceding denominator </li></ul>
13. 14. Amount to administer Available dosage Ordered dosage
14. 15. Dosage Calculation Using Dimensional Analysis (cont’d) <ul><li>Cancel “like” units on right of equation; remaining unit of measure should be what is desired </li></ul>
15. 16. Dimensional Analysis Using Conversion Factor <ul><li>When a conversion factor is needed, the conversion factor is placed as the second fraction inside the equation </li></ul><ul><li>Match numerator of conversion factor with denominator of previous fraction </li></ul>