Aerosol-Humidity-CPT
What is humidity?
Water in gaseous state
Water vapor
Molecular water in gas
What is potential humidity?
The amount of water vapor a gas
can hold.
What determines potential
humidity.
Determined by temperature of the
gas
Aerosol-Humidity-CPT
In relation to humidity, define
“saturated”
When the gas has reached its
potential at that temperature
Define absolute humidity & how it is
expressed.
Amount of water weight held in the
gas
Expressed in mg/L
What is the formula for relative
humidity and how is it expressed?
R.H. = Absolute humidity x 100
Potential humidity
Expressed as a percent
Aerosol-Humidity-CPT
What is the relative humidity of
alveolar gas?
100%
Alveolar gas holds approximately
how much water?
44mg/L at 37oC
How much pressure is exerted by
water vapor in alveolar gas?
At 37oC and 100% R.H. the pressure
exerted by water vapor is 47mmHg
Aerosol-Humidity-CPT
Define humidity deficit
Amount of humidity in alveolar gas
minus the amount of humidity
inspired
How is humidity normally supplied
to inspired gas?
By nasopharyngeal and
oropharyngeal passages
If humidity is not supplied by the
normal routes, how will inspired
gas obtain its humidity?
Moisture will be taken from tracheal
mucosal blanket which dries and
thicken secretions
Aerosol-Humidity-CPT
What can inadequate humidification
cause? Name 4.
Decreased cilia activity
Decreased movement of mucous
Inflammation and necrosis of pulmonary epithelium
Retention of secretions
Bacterial culture media
Atelectasis
Pneumonia
What are the 2 indications for
humidification?
To prevent dry gas from drying
mucosa
To provide near body humidity
when upper airway function is
impaired or bypassed
True or False
A humidifier delivers 100% R.H. at
30oC, therefore delivering 100%
humidity to the patient.
False – the temperature increases
to 37oC at the patient. Less than
100% R.H. is delivered
Aerosol-Humidity-CPT
True or False
If the temperature of a gas that has
a RH of 100%, decreases, the RH
will remain the same but the
potential and actual humidity will
decrease.
False
What is an Aerosol?
Water particles suspended in air
Particulate water in a gas
Mist
Fog
What is “stability of an aerosol”
The ability of particles to remain
stable while suspended in a gas
Aerosol-Humidity-CPT
Name three factors affecting the
stability of an aerosol
Concentration
Size
Relative humidity
How does concentration affect
aerosol stability
Number of particles – more
particles will bump together and
become larger and rain out
How does particulate size affect
aerosol stability?
Large particles rain out
Aerosol-Humidity-CPT
How does relative humidity affect
aerosol stability?
Low relative humidity of the gas
causes particles to evaporate
With regard to aerosols, define
penetration
Depth within the tracheobronchial
tree that a particle reaches
In regards to aerosols, define
deposition
Particles will rain out at a particular
area
Aerosol-Humidity-CPT
Name 4 factors influencing
penetration and deposition of an
aerosol
Gravity
Kinetic motion
Inertial impaction
Ventilatory pattern
How does gravity influence the
penetration and deposition of an
aerosol?
The larger (or more dense) the
particle, the more likely it is to
deposit or rain out
How does kinetic motion influence
the penetration and deposition of
an aerosol?
The more particles move, the more
likely to bump together, coalesce
and rain out
Aerosol-Humidity-CPT
How does inertial impaction
influence the penetration and
deposition of an aerosol?
When airways narrow and alter direction,
aerosol particles may continue on their same
path and deposit by bumping into airway
walls
How does ventilatory pattern
influence the penetration and
deposition of an aerosol?
Alterable factor
Ideal pattern is slow, deep breath
with an inspiratory hold
Name 3 methods of clearing an
aerosol from the lungs?
Mobilization of the mucus blanket
Cough
Lymphatic uptake
Phagocytes
Mechanical suctioning
Aerosol-Humidity-CPT
What are the 4 indications of aerosol
therapy?
To thin secretions
To improve cough
To deliver medication
Humidification of artificial airways
Name 4 hazards of aerosol therapy
Swelling of dried secretions
Bronchospasm
Fluid overload
Nosocomial infection
Aerosols can cause bronchospasm
particularly in what type of patient?
Pts with reactive airways
Asthma
Aerosol-Humidity-CPT
With regard to humidifiers, what are
the factors that influence RH?
Surface area of exposure – the size of the
bubble
Time of contact – flow and depth of water
Temperature
Name 4 types of humidifiers.
Passover
Bubble diffuser or bubble type
Jet
Wick
Membrane
Heat & moisture exchanger
How does a Passover humidifier
work?
Gas passes across surface of
water. Water evaporates into the
gas, increasing the humidity of gas
Aerosol-Humidity-CPT
Describe how a bubble humidifier
works.
Gas forced through a straw under water
The smaller the bubbles, the greater RH
The deeper the water, the greater the RH
The higher the temperature, the greater the
RH
When is a bubble humidifier used?
Used with cannula to prevent dry
gas from being delivered
At 37oC, what is the approximate
RH of a bubble humidifier?
Less than 40%
Aerosol-Humidity-CPT
How does a jet humidifier work?
Uses the Bernoulli principle to draw
gas up a tube
Produces an aerosol that is baffled
out to produce humidity
Name three types of heated
humidifiers?
Cascade types
Wick types
Membrane types
Heat & moisture exchangers
How does a heated cascade type
humidifier work?
Can it deliver 100% body humidity?
Uses a grid network to spread a thin layer of water,
through which the gas passes before delivery to
patient.
Yes
Aerosol-Humidity-CPT
Describe how a wick humidifier
works.
At body temperature, how many
mg/L of humidity can it deliver?
Heater surrounds absorbent paper which soaks up
water from the bottom of humidifier – gas passes
warm wet paper and water is evaporated – water
level is maintained constant by a feed apparatus.
44mgL
Describe how the artificial nose
works and when it should be used.
Passive humidifier – captures heat and
moisture for exhaled gas and returns them to
pt on next inspiration
Short term use with normal body
temperature and minimal secretions
Name 3 types of nebulizers
Jet
Babbington or hydrosphere
Ultrasonic
Spinning disk
Aerosol-Humidity-CPT
Name three types of jet nebulizers
Large reservoir
Small volume (standard jet)
Mainstream nebulizer
Sidestream nebulizer
On what principle are jet nebulizers
based?
Bernoulli principle
How are jet nebulizers powered?
Pneumatically powered
Aerosol-Humidity-CPT
Describe what a large reservoir jet
nebulizer is used for, its capacity,
and its relative humidity range.
For long-term nebulization
Holds more than 250ml
Deliver 50-75% RH
Describe what the standard jet
nebulizer is used for & its capacity.
Used for IPPB
Used primarily for delivery of
medication
Holds less than 20cc
How does a mainstream nebulizer
work?
Gas flows directly through
nebulizing chamber
Aerosol-Humidity-CPT
Describe the side stream nebulizer
and the particulate size range.
Aerosol is not created in main gas
flow
About 50% of particles in 1-5
micron size
Describe the Babbington nebulizer
and the particulate size rage.
Based on Bernoulli principle – gas enters hollow
glass sphere with hole in the side of it – film over
port from dripping fluid on outer surface – gas
exits ports in sphere – gas stream bursts film
creating aerosol – produces a high volume aerosol
– particles usually 3- 5 microns
Describe the Ultrasonic nebulizer
and the particulate size rage.
Converts electrical energy into mechanical energy
Uses a piezoelectric disc
Frequency is predetermined by FCC
Amplitude is adjustable & will alter output
Has a high output (up to 6cc/min)
90% of particles 0.5 to 3 microns
Aerosol-Humidity-CPT
Describe the spinning disk
nebulizer and the approximate RH
delivered.
Used as room humidifiers
Uses a rotating platter
Drips fluid onto the surface of the spinning platter
Centrifugal force spins the fluid off the platter into
the breaker combs, creating the aerosol stream
Caution must be taken to avoid contamination
Delivers approximately 25-75% RH
What is the therapeutic range of an
aerosol particle to reach alveoli?
1.0 – 3.0 microns
What happens to particles smaller
than the therapeutic range to reach
the alveoli?
Particles less than 1.0 microns are
exhaled back out
Aerosol-Humidity-CPT
What happens to particles larger
than the therapeutic range to reach
the alveoli?
Particles larger than 3.0 microns
are deposited before reaching
alveoli
Name a potential hazard of an
electrical nebulizer.
Potential shock
How would you position the patient
to perform postural drainage on the
apical segment of the right upper
lobe?
Semi-Fowler’s at 45 degree angle
Aerosol-Humidity-CPT
How would you position the patient
to perform postural drainage on the
anterior segment of the right upper
lobe?
Head of bed flat, patient supine
How would you position the patient
to perform postural drainage on the
posterior segment of the right
upper lobe?
Head of bed flat, patient ¼ or higher
from prone, right side up
How would you position the patient
to perform postural drainage on the
medial segment of the right middle
lobe?
Head of bed down 12-14”, right side
up, ¼ or higher supine
Aerosol-Humidity-CPT
How would you position the patient
to perform postural drainage on the
lateral segment of the right middle
lobe?
Right side up, head of bed down 1618 inches
How would you position the patient
to perform postural drainage on the
superior segment of the right lower
lobe?
Head of bed flat, patient prone with
pillows under abdomen
How would you position the patient
to perform postural drainage on the
anterior basal segment of the right
lower lobe?
Head of bed down 18-20”, patient
supine
Aerosol-Humidity-CPT
How would you position the patient
to perform postural drainage on the
lateral basal segment of the right
lower lobe?
Head of bed down 18-20”, pt lying
right side up
How would you position the patient
to perform postural drainage on the
posterior basal segment of the right
lower lobe?
Head of bed down 18-20”, patient
prone
How would you position the patient
to perform postural drainage on the
anterior segment of the left upper
lobe?
Head of bed flat, patient supine
Aerosol-Humidity-CPT
How would you position the patient
to perform postural drainage on the
apical-posterior segment of the left
upper lobe?
Head of bed up 30 degrees, patient
left side up, ¼ or higher prone
How would you position the patient
to perform postural drainage on the
superior lingula segment of the left
upper lobe?
Head of bed down 12-14”, patient
left side up, ¼ or higher supine
How would you position the patient
to perform postural drainage on the
inferior lingula segment of the left
upper lobe?
Head of bed down 12-14”, patient
left side up, ¼ or higher supine
Aerosol-Humidity-CPT
How would you position the patient
to perform postural drainage on the
superior segment of the left lower
lobe?
Head of bed flat, patient prone with
pillows under abdomen
How would you position the patient
to perform postural drainage on the
anteriomedial segment of the left
lower lobe?
Head of bed down 18-20”, patient
supine
How would you position the patient
to perform postural drainage on the
lateral basal segment of the left
lower lobe?
Head of bed down 18-20”, patient
left side up
Aerosol-Humidity-CPT
How would you position the patient
to perform postural drainage on the
posterior basal segment of the left
lower lobe?
Head of bed down 18-20”, patient
prone
Name 6 relative contraindications of
Postural drainage?
Empyema
Head injuries
Flail chest
Unstable cardiac status
Wounds
COPD
Spinal injuries
Obesity
Pneumothorax
Pregnancy
Recent meals or tube feeding
What is percussion and when is it
indicated?
Clapping chest wall with cupped hands,
relaxed wrist to set up vibrations to loosen
secretions
Indicated when difficult to mobilize
secretions or when postural drainage alone
may not be enough
Aerosol-Humidity-CPT
Name 6 relative contraindications of
Percussion?
Empyema
Flail chest
Wounds
Frank hemoptysis
Anticoagulant therapy
Pain or pt intolerance
TB
Metastasized Cancer
What are the instructions for
performing percussion
Avoid sternum, spine & bony structures
May use sheet or towel to avoid
slapping
Examine skin for any effect
Percuss each segment for 3-5 min
Describe how a vibration is
performed.
Tense arms and keep them straight.
Shake from shoulder during patient
exhalation only.
Aerosol-Humidity-CPT
When is a vibration performed?
In conjunction with percussion
after each segmental percussion to
move secretions to large airways
Or alone when percussion is not
tolerated
Name 4 instructions on using
mechanical percussors and
vibrators.
Only to lung area – avoid kidneys, etc.
Avoid bony structures
Avoid breast tissue in females
Use towels or sheet to prevent slapping
Use electrical precautions – avoid water;
avoid hazardous gas environment
Name some therapies used for
bronchial hygiene other than CPT
PEP – Positive Expiratory Pressure
Flutter Valve
High Frequency Chest Wall
Oscillation Therapy
Aerosol-Humidity-CPT
What are the indications for PEP
therapy?
Aid in removal of retained
secretions, Atelectasis, and
treatment of Cystic Fibrosis
What are the hazards of PEP
therapy?
Risk of barotraumas and
homodynamic compromise
What are the indications for Flutter
Valve therapy?
Aid in removal of retained
secretions, Atelectasis, and
treatment of Cystic Fibrosis
Aerosol-Humidity-CPT
What are the hazards of Flutter
Valve therapy?
Risk of barotraumas and
homodynamic compromise
What are the indications for High
Frequency Chest Wall Oscillation
therapy?
Mucous plugging Retained
secretions
Treatment of Cystic Fibrosis
What are the hazards of High
Frequency Chest Wall Oscillation
therapy?
Unstable chest fractures may cause
pneumothorax