Reading...
Play button
Play button
Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
30 Cards in this Set
- Front
- Back
|
What is humidity?
|
- water in a gaseous state
- water vapor - molecular water in gas |
|
|
What is potential humidity determined by?
|
- temperature & gas
|
|
|
When is humidity considered saturated?
|
- when the gas has reached its potential at that temperature
|
|
|
What is absolute humidity?
|
- amount of water weight held in the gas (mg/L)
|
|
|
What is the formula for relative humidity?
|
absolute humidity
___________________ x 100 potential humidity |
|
|
How much humidity does alveolar gas hold at 37 degrees Celsius?
|
- approximately 44mg/L of humidity
|
|
|
What is the pressure exerted by water vapor at 37 C and 100% relative humididty (RH)?
|
- 47mmHg
|
|
|
What is the humidity deficit?
|
- amount of humidity in alveolar gas minus the amount of humidity inspired from room air
|
|
|
How is humidity normally supplied to inspired gas?
|
- by nasal & oropharynx passages
- if not supplied by the nose, moisture will be taken from tracheal mucosal blanket (this will dry & thicken secretions) |
|
|
What can inadequate humidification cause?
|
- decreased ciliary activity
- decreased movement of mucus - inflammation & necrosis of pulmonary epithelium - retention of secretions - bacterial culture media - atelectasis - pneumonia |
|
|
What are the indications for humidification?
|
- to prevent dry gas from drying mucosa
- to provide near body humidity when upper airway function is impaired |
|
|
Where does humidity retain moisture in the body?
|
- in the respiratory tract
|
|
|
What happens if you increase the temp. of a gas?
(examples in PowerPoint page 3) |
- you will increase the potential humidity of the gas, thus decreasing its relative humidity (& vice versa)
|
|
|
If at 30 degrees Celsius, a cascade humidifier puts out 100% RH, and then the temp. is increased to 37 C, what will the resulting RH delivered to the patient be?
|
- less than 100% RH
|
|
|
What is aerosol?
|
- water particles suspended in air
- particulate water in a gas - mist - fog |
|
|
What is the stability of an aerosol?
|
- the ability of particles to remain stable while suspended in a gas
|
|
|
What are the factors affecting the stability of an aerosol?
|
- concentration (# of particles; more particles bump together)
- size (large particles "rain out") - RH (low relative humidity of the gas causes particles to evaporate) |
|
|
What is penetration (aerosol)?
|
- depth of tracheobronchial tree that a particle reaches
|
|
|
What is deposition (aerosol)?
|
- where particles "rain out" and land at a particular area
|
|
|
How does gravity influence the penetration & deposition of an aerosol?
|
- the larger the particle, the more likely it is to deposit or "rain out"
|
|
|
How does kinetic motion influence the deposition & penetration of an aerosol?
|
- the more particles move, the more likely they are to bump together, coalesce, and rain out
|
|
|
How does inertial impaction influence the penetration & deposition of aerosol?
|
- when airways narrow & alter direction, particles may continue on their same path and deposit by bumping airway walls
|
|
|
How does ventilatory pattern influence the penetration & deposition of aerosol?
|
- alterable factor influencing deposition & retention
- IDEAL PATTERN is slow, w/ deep breaths, utilizing an inspiratory hold |
|
|
What is clearance?
|
- aerosols add liquid to the lung; the liquid must be cleared to avoid accumulation
|
|
|
What are the methods of clearance?
|
- mobilization of mucous blanket
- cough - lymphatic uptake - phagocytes - mechanical suctioning |
|
|
What are the indications for aerosol?
|
- to thin secretions
- improve cough - deliver medications - humidification of artificial airways |
|
|
What are the hazards of aerosol?
|
swelling of dried secretions
- causes airway obstruction - can be fatal - usually patients w/ a weak cough cause bronchospasm - reactive airways - asthma fluid overload - usually use of high output systems w/ infants - CHF |
|
|
What are the factors influencing RH w/ equipment humidifiers?
|
- TEMPERATURE!
- surface area exposure (size of the bubble) - time of contact (flow & depth of water) |
|
|
What are the characteristics of a Passover (kosher) humidifier?
|
- gas passes across the surface of water which may be heated
- cascade humidifier w/ tower removed - Wick or membrane |
|
|
What are the characteristics of a Bubble diffuser/type humidifier?
|
- gas forced through straw under water
- smaller bubble = greater RH (more surface area for gas to come into contact w/ water) - deeper water = greater RH - used w/ cannula, etc. to prevent dry gas from being delivered (most common in hospitals) - usually deliver approximately 40% RH at body temp. or less |
