Chapter 39, Bland Aerosol & Humidity Flashcards
what is humidity?
simply put, humidity is water vapor in its gaseous or molecular form
why do we need humidity?
primary:
- humidify dry medical gases
- overcoming humidity deficit when upper airway is bypassed
secondary:
- treating bronchospasm cased by cold air
what are some clinical signs and symptoms of inadequate airway humidification
- atelectasis
- dry, nonproductive cough
- increased airway resistance
- increased incidence of infection
- increased work of breathing
Heat moisture exchange (HME)
Describe natural HME and artificial HME
Natural HME:
Nose
- mouth is also natural HME, however not as effective
-nose will heat and humidify gas on inspiration, cools and reclaims H20 from gas exhaled
Artificial HME:
Device
what is an active humidifier
an active humidifier is going to add heat, water or both to the device/patient interface
Examples: bubble humidifier, Passover humidifier, nebulizer of blank aerosol
what is a passive humidifier
a passive humidifier will recycle exhaled heat and humidity from the patient
Example: traditional heat moisture exchangers, AKA HME “Artificial Nose” and Artificial Airway (ETT/Trach)
How to passover humidifier pass gas
passover humidifiers pass gas over a large surface area of water
what are some advantages over bubble humidifier?
- maintains saturation at high flow rates
- add little or no flow resistance to spontaneous breathing circuits
- do not generate any aerosols that can spread infection
What are the 3 types of passover humidifiers?
- simple reservoir
- wick
- membrane
what is a simple reservoir?
a simple reservoir directs gas over the surface of a volume of water. most commonly used for high flow and invasive ventilation
what is a wick (type of passover)
wick- uses an absorbent material to increase the surface area for dry air to interfere with heated water. uses a porous water absorbent material to draw water into a fine honeycomb like structure
what is a membrane (type of passover)
a membrane separates heated water from the gas stream by means of hydrophobic membrane
what is a bland aerosol?
What is it?
- liquid particles suspended into gas
- VS humidity which is water in gas phase
how is bland aerosol delivered?
delivery of the following “liquids”
- sterile water
- sterile saline: hypotonic, isotonic or hypertonic
what are some indications for bland aerosol
- presence of upper airway edema (cool bland aerosol)
- laryngotracheobronchitis
- subglottic edema
- presence of bypassed upper airway
- need for sputum specimen or mobilization of secretions
delivery devices of bland aerosol: large volume jet nebulizer
what is this device?
it is the most common device used for bland aerosol therapy
- pneumatically powdered and connected directly to a flowmeter and compressed gas source
- variable air-entrainment port allows air mixing to increase flow rates and to alter FiO2 levels
how does a large volume jet nebulizer work?
- liquid particles are generated by passing gas at a high velocity through small jet orifice
- low pressure jet draws fluid from reservoir up siphon tube
- H20 is shattered into liquid particles
- smaller particles leave nebulizer through outlet port in gas stream
delivery devices for bland aerosol
Ultrasonic nebulizer
what is it?
- electronically powered device that uses piezoelectric crystal to generate aerosol
- crystal transducer converts radio waves into high frequency mechanical vibrations that produce aerosol
what are examples of airway appliances for bland aerosol?
- aerosol mask
- face tent
- t-tube
- tracheostomy mask
All used with large bore tubing to minimize flow resistance and prevent occlusion by the condensate
When do you cool bland aerosol?
Hyperthermia
- patient is running a high temperature
- should heater be turned up or down
when do you hear a bland aerosol?
Hypothermia
- found down from near drowning/cold temperatures
- patient will not be declared deceased unless they have been warmed
- we will use heated humidity to accomplish this
What is an artificial HME?
(Heat moisture exchange)
- passively heats/humidifies using humidity from patient expiration
- captures exhaled heat and moisture and returns up to 70% of the heat and humidity to the patient during the next inspiration
What are sputum induction?
A type of bland aerosol that involves a short-term application of high density hypertonic saline (3% to 10%) aerosols to airway
what are some advantages to sputum induction bland aerosol?
- cost- effective, safe method for diagnosing tuberculosis, and lung cancer
- aid in mucociliary clearance
- high-density aerosols are most easily generated by using ultrasonic nebulization
