Airway Clearance Flashcards
(26 cards)
What is MCC?
Primary clearance mechanism of the airways
Protection mechanism of lungs (lower resp tract)
What 2 components does MCC apparatus consist of?
MUCUS
- 2 layers
- mechanical, chemical and biological barrier
CILIA
- move particulate material caught in mucus towards pharnyx
What are the 2 layers of mucus and their characteristics?
Sol Layer (periciliary fluid)
- thin, watery aqueous fluid bathing cilia
- minimal resistance to cilial mvt
- low viscosity and elasticity
Gel Layer (mucus layer)
- elastic and viscous
- moved towards the mouth
What are the 5 factors increasing MCC?
posture - using gravity
exercise
environment - inhaling particulate matter/irritated airway wall)
drugs
hydration
What 3 factors decrease MCC?
increased age
sleep
disease/injury (esp resp)
Why do smoking, chronic bronchitis and infection lead to increased mucus volume
Smoking and chronic bronchitis:
Increased size and number of secretory cells
Infection eg pneumonia: inflammatory reaction
Explain how dehydrated Sol layer contributes to MCC impairment
Decreased depth of sol layer dehydrates the cilia - they cannot beat effectively
eg in CF due to changes in ion transport
How else might asthma and CF impair MCC?
They alter the rheological properties of the mucus - thickness and stickiness. This makes it harder to clear as it adheres to the airway walls.
Name the 3 impairments of MCC related to alteration of cilial action
- decreased cilial beat frequency
- destruction of cilia
- immotile cilia (dont move)
Explain decreased cilial beat frequency
MCC is slower so mucus builds up
ageing, anaesthetic
Name scenarios/conditions where cilia are destroyed
- smoking, chronic bronchitis. bronchiectasis
- infection especially repeated in same area
- mechanical damage eg ETT
- burns
- chemical damage
Which disorders cause immotile cilia
Genetic disorders
primary cilial dyskinesia
Kartagener’s syndrome - younger patients
Explain the importance of cough and where it can clear secretions from
- main backup mechanism after MCC to clear foreign matter/secretions from airways
- centrally located airways
What are the 4 components of an effective cough?
- deep inspiration to TLC
- breath hold against closed glottis
- contraction of expiratory muscles causing big change in intrathoracic pressure
- glottis opens and rapid expulsion of air
How does the large EFR generated by cough clear secretions. Hint 2PLGF
- acceleration of airflow (gas) across secretions (liquid) lining the airway walls = cephalad (mouthward) movement of secretions
- momentum from the gas is transferred to the liquid to detach it from airway walls
Explain the two types of flow
Mist Flow
- high EFR
- liquid carried as small droplets in the gas
- coughing
Annular Flow
- lower EFR
- surface of liquid layer moves in waves
- huffing
What are the 5 reasons (and example of each) for an ineffective cough which lead to a secretion movement problem?
- inability to take deep breath in
- weak inspiratory muscles
- chest wall/abd pain - inability to close glottis
- neuro - weak expiratory muscles
- SCI deinnervated - excessive dynamic compression (closure)
- floppy airways close with the pressure - depressed cough reflex
- eg sedation
what are the 4 components of an effective huff
- breathe in to specified volume
- keep glottis and mouth open
- contract abdominal muscles
- controlled forced expiration to specified volume
describe a mid to low lung volume huff
- medium breath in and exhale longer
- EPP occurs towards peripheral airways
describe a high to mid lung volume huff
- big breath in and short sharp exhalation
- EPP occurs closer to central airways
what are the 4 stages/aims of airway clearance
- open up airways to get air behind the mucus
- ventilate airways distal to mucus - loosen/unstick the secretions from the small airways
- mobilise secretions from more peripheral to central airways
- EFR increase to move secretions up
- expiratory flow bias - clear secretions from central airways
what are the 3 types of breathing exercises for airway clearance
active cycle of breathing techniques (ACBT)
forced expiration technique (FET)
autogenic drainage (AD)
what are the 3 components of ACBT
- slow deep breathing (thoracic expansion and inspiratory hold)
- breathing control
- FET (huffs and breathing control)
what 2 components make up FET
huffs - 1-2
breathing control
- relaxed breathing
- reduce bronchospasm, desaturation, fatigue
