Chapter 39, Bland Aerosol & Humidity

Question 1

what is humidity?

Answer 1

simply put, humidity is water vapor in its gaseous or molecular form

Question 2

why do we need humidity?

Answer 2

primary:
- humidify dry medical gases
- overcoming humidity deficit when upper airway is bypassed

secondary:
- treating bronchospasm cased by cold air

Question 3

what are some clinical signs and symptoms of inadequate airway humidification

Answer 3

• atelectasis
• dry, nonproductive cough
• increased airway resistance
• increased incidence of infection
• increased work of breathing

Question 4

Heat moisture exchange (HME)

Describe natural HME and artificial HME

Answer 4

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

Question 5

what is an active humidifier

Answer 5

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

Question 6

what is a passive humidifier

Answer 6

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)

Question 7

How to passover humidifier pass gas

Answer 7

passover humidifiers pass gas over a large surface area of water

Question 8

what are some advantages over bubble humidifier?

Answer 8

• 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

Question 9

What are the 3 types of passover humidifiers?

Answer 9

• simple reservoir
• wick
• membrane

Question 10

what is a simple reservoir?

Answer 10

a simple reservoir directs gas over the surface of a volume of water. most commonly used for high flow and invasive ventilation

Question 11

what is a wick (type of passover)

Answer 11

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

Question 12

what is a membrane (type of passover)

Answer 12

a membrane separates heated water from the gas stream by means of hydrophobic membrane

Question 13

what is a bland aerosol?

Answer 13

What is it?

• liquid particles suspended into gas
• VS humidity which is water in gas phase

Question 14

how is bland aerosol delivered?

Answer 14

delivery of the following “liquids”

• sterile water
• sterile saline: hypotonic, isotonic or hypertonic

Question 15

what are some indications for bland aerosol

Answer 15

• presence of upper airway edema (cool bland aerosol)
• laryngotracheobronchitis
• subglottic edema
• presence of bypassed upper airway
• need for sputum specimen or mobilization of secretions

Question 16

delivery devices of bland aerosol: large volume jet nebulizer

what is this device?

Answer 16

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

Question 17

how does a large volume jet nebulizer work?

Answer 17

• 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

Question 18

delivery devices for bland aerosol
Ultrasonic nebulizer

what is it?

Answer 18

• electronically powered device that uses piezoelectric crystal to generate aerosol
• crystal transducer converts radio waves into high frequency mechanical vibrations that produce aerosol

Question 19

what are examples of airway appliances for bland aerosol?

Answer 19

• aerosol mask
• face tent
• t-tube
• tracheostomy mask

All used with large bore tubing to minimize flow resistance and prevent occlusion by the condensate

Question 20

When do you cool bland aerosol?

Answer 20

Hyperthermia

• patient is running a high temperature
• should heater be turned up or down

Question 21

when do you hear a bland aerosol?

Answer 21

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

Question 22

What is an artificial HME?

Answer 22

(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

Question 23

What are sputum induction?

Answer 23

A type of bland aerosol that involves a short-term application of high density hypertonic saline (3% to 10%) aerosols to airway

Question 24

what are some advantages to sputum induction bland aerosol?

Answer 24

• 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