1. Calculations Used in Patient Assessments
Chapter 7
Calculations Used in Patient Assessments
Copyright © 2020 by Mosby, an imprint of Elsevier Inc. All rights reserved.

2. Calculating for Intake and Output, Weight, Length, and Temperature
Recalling equivalent apothecary and metric measures
Computing equivalents between the apothecary and metric systems by using dimensional analysis to calculate intake and output (I&O), weights, and lengths
Converting from the Fahrenheit scale to the Celsius scale
Converting from the Celsius scale to the Fahrenheit scale

3. Apothecary/Metric Equivalents
What types of measures are included in this table? Are weight measures included? What about length and volume measures?
Volume and weight measures are included in this table, but length measures are not.

4. Calculating Aspects of a Patient Assessment
Nurses use the apothecary or metric equivalents to calculate patient I&O, length, and weight.
Nurses may need to convert between the Celsius and Fahrenheit systems for calculating patient weight.
Take your temperature in Fahrenheit. Convert the value to centigrade.

5. Calculating Intake and Output
The unit of measure for I&O is typically milliliters.
I&O measurements may require conversion between household, apothecary, and metric systems.
Convert 2 cups to milliliters
Answer: 480 mL

6. Calculating Patient Weight
For example:
Convert 120 lb to kg
Convert 120 lb to kg
Answer: x kg = 1 kg × 120 lb = kg
2.2 lb

7. Calculating Patient Weight
Convert 120 lb to kg
2.2 lb = 1 kg
120 lb = x kg
Set up would look like this:
2.2x = 120
x = 54.54= 54.5 kg

8. Calculating Patient Length
For example:
Convert 66 in to cm
1 in = 2.5 cm
66 in = _x_ cm
X = 165 cm
Convert 66 in to cm
x cm = 2.5 cm × 66 in = 165 cm
1 in

9. Converting Celsius and Fahrenheit Temperatures
BOX 7-2: CONVERTING CELSIUS AND FAHRENHEIT TEMPERATURES
Fahrenheit to Celsius
Celsius to Fahrenheit
Subtract 32
Divide by 1.8
Multiply by 1.8
Add 32
What is the freezing point of water in degrees Fahrenheit? What is the freezing point of water in degrees Celsius?
The freezing point of water is 32° F on the Fahrenheit scale and 0° C on the Celsius scale.

11. Converting Celsius and Fahrenheit Temperatures
Use either of following formulas:
For example:
99° F equals how many degrees Celsius?
Alternatively, use the rules in Box 7-2.
100° C equals how many degrees Fahrenheit?
99° F equals how many degrees Celsius?
Following the proportion method, the proportion should be the following:
C : 99 − 32 :: 5 : 9
Multiplying the means, (99 – 32) and 5, and extremes, C and 9, you get C = Therefore, 99° F equals 37.2° C.
100° C equals how many degrees Fahrenheit?
Following the rules for converting Celsius to Fahrenheit, you multiply 100 by 1.8, which yields 180. Then add 32 to 180. This yields 212. Therefore, using the rules listed in Box 7-2, 100° C is equal to 212° F (the boiling point of water).

12. Converting to Celsius C° = F°-32 1.8 99°-32= 67
C °= (round to the tenths)
C °= 37.2
Copyright © 2020 by Mosby, an imprint of Elsevier Inc. All rights reserved.

13. Converting to Farenheit
F° = 1.8C° + 32
F° = 1.8 * =
F° = =
F° = 98.6
Copyright © 2020 by Mosby, an imprint of Elsevier Inc. All rights reserved.