Chapter 2 Flashcards
What is humidity?
The quantity of moisture in air or gas that is
caused by the addition of water in a gaseous
What are some other names for humidity?
molecular water
invisible moisture
What are the clinical uses for humidity?
To provide 100% body humidity of the
When inspired is fully saturated at 37 degrees it
holds how much liters of gas?
44
What is absolute humidity?
Amount of water in a given volume of gas;
measurement is expressed in milliliters per liter
What is relative humidity?
A ratio between the amount of water in a given
volume of gas at the maximum amount it is
What is the formula for relative humidity?
RH = AH/capacity x 10
What is the formula for absolute humidity?
AH = RH x capacity
What is body humidity?
The relative humidity at body temp and is
expressed as a percentage.
What is the formula for body humidity?
BH = AH/44 ×100
What is the capacity of water at body
temperature?
44mg/dL
What is humidity deficit?
Inspires air that is not fully saturated at body
temperature.
What is the formula for humidity deficit?
HD / 44 × 100
Gas or water vapor pressure < 47 does what?
dries secretions, making them thicker and more
difficult to mobilize
What is a pass-over (nonheated) humidfier?
Gas passes over the surface of the water picking
up moisture and delivering it to the patient
How much body humidity does a passover
humidifier give?
35-40%
What is a wick (heated) humidifier?
Gas from the flowmeter or ventilator enters the
humidfier and is exposed to the wick which is
Most non-heated humidifiers have a pressure
pop of valve set at what?
2 psi
The humidifier should be replaced how often?
every 24 hours
What is an HME?
As the patient exhales body humidity enters the
HME and and condenses water into it
HME produces how much body heat?
70-90%
What is aersol?
Water in particle form?
What are the clinical uses for aerosol therapy?
- [HHN] or ultrasonic nebulizer [USN]).
What are some hazards of aerosol therapy?
- Bronchospasm: administration of a
What is gravitational sedimentation?
The larger a particle is, the more effect gravity
has on it and the sooner it will deposit.
What is browian movement?
Affects particles of 0.1 mm or smaller in size,
which will deposit too soon (possibly in the
What is inertial impaction?
Larger particles have greater inertia, which keeps
them moving in a straight line. Because they
cannot make directional changes in the airway,
What are hygroscopic properties?
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.
What is ventilatory pattern?
To obtain optimal particle penetration, the
patient should be instructed to take slow,
moderately deep breaths with a 2- to 3-second
What is a Jet Neb?
(jet), resulting in a drop in pressure that draws
water up the capillary tube into the gas stream
How much particles do mechanical nebulizers
produce? What size range?
50%
0.5 - 3
