Chapter 2

Question 1

What is humidity?

Answer 1

The quantity of moisture in air or gas that is
caused by the addition of water in a gaseous

Question 2

What are some other names for humidity?

Answer 2

molecular water
invisible moisture

Question 3

What are the clinical uses for humidity?

Answer 3

To provide 100% body humidity of the

Question 4

When inspired is fully saturated at 37 degrees it
holds how much liters of gas?

Answer 4

44

Question 5

What is absolute humidity?

Answer 5

Amount of water in a given volume of gas;
measurement is expressed in milliliters per liter

Question 6

What is relative humidity?

Answer 6

A ratio between the amount of water in a given
volume of gas at the maximum amount it is

Question 7

What is the formula for relative humidity?

Answer 7

RH = AH/capacity x 10

Question 8

What is the formula for absolute humidity?

Answer 8

AH = RH x capacity

Question 9

What is body humidity?

Answer 9

The relative humidity at body temp and is
expressed as a percentage.

Question 10

What is the formula for body humidity?

Answer 10

BH = AH/44 ×100

Question 11

What is the capacity of water at body
temperature?

Answer 11

44mg/dL

Question 12

What is humidity deficit?

Answer 12

Inspires air that is not fully saturated at body
temperature.

Question 13

What is the formula for humidity deficit?

Answer 13

HD / 44 × 100

Question 14

Gas or water vapor pressure < 47 does what?

Answer 14

dries secretions, making them thicker and more
difficult to mobilize

Question 15

What is a pass-over (nonheated) humidfier?

Answer 15

Gas passes over the surface of the water picking
up moisture and delivering it to the patient

Question 16

How much body humidity does a passover
humidifier give?

Answer 16

35-40%

Question 17

What is a wick (heated) humidifier?

Answer 17

Gas from the flowmeter or ventilator enters the
humidfier and is exposed to the wick which is

Question 18

Most non-heated humidifiers have a pressure
pop of valve set at what?

Answer 18

2 psi

Question 19

The humidifier should be replaced how often?

Answer 19

every 24 hours

Question 20

What is an HME?

Answer 20

As the patient exhales body humidity enters the
HME and and condenses water into it

Question 21

HME produces how much body heat?

Answer 21

70-90%

Question 22

What is aersol?

Answer 22

Water in particle form?

Question 23

What are the clinical uses for aerosol therapy?

Answer 23

3. [HHN] or ultrasonic nebulizer [USN]).

Question 24

What are some hazards of aerosol therapy?

Answer 24

1. Bronchospasm: administration of a

Question 25

What is gravitational sedimentation?

Answer 25

The larger a particle is, the more effect gravity
has on it and the sooner it will deposit.

Question 26

What is browian movement?

Answer 26

Affects particles of 0.1 mm or smaller in size,
which will deposit too soon (possibly in the

Question 27

What is inertial impaction?

Answer 27

Larger particles have greater inertia, which keeps
them moving in a straight line. Because they
cannot make directional changes in the airway,

Question 28

What are hygroscopic properties?

Answer 28

Aerosol particles are hygroscopic (retain
moisture). As they travel down the airway, they
may increase in size as they retain moisture,
which may alter the time at which they deposit.

Question 29

What is ventilatory pattern?

Answer 29

To obtain optimal particle penetration, the
patient should be instructed to take slow,
moderately deep breaths with a 2- to 3-second

Question 30

What is a Jet Neb?

Answer 30

(jet), resulting in a drop in pressure that draws
water up the capillary tube into the gas stream

Question 31

How much particles do mechanical nebulizers
produce? What size range?

Answer 31

50%
0.5 - 3