ACBT

Question 1

Airway clearance techniques

Answer 1

used to supplement body’s MCC when it is impaired by disease.
Transport secretions to proximal airways
2 main mechanisms:
1. allow air move behind obstruction and ventilate the regions distally and
2. change expiratory airflow in such a was as to propel secretions proximally.

Question 2

ACBT: purpose

3 components

Answer 2

mobilise and clear secretions
maintain O2 sats

breathing control
thoracic expansion exercises
Forced expiration technique

Question 3

Breathing control

Answer 3

normal gentle breathing at tidal volume using lower chest during diaphragmatic breathing
relaxation of upper chest and shoulders
can place hands over diaphragm to encourage lower breathing and upper chest relaxation
Allows for recovery from fatigue O2 desaturated, bronchospasm and breathlessness which may occur during more active components of the cycle

Question 4

thoracic expansion exercises

- deep breathing

Answer 4

slow and controlled inspiration through nose, quiet expiration
May use 3 sec inspiratory hold
facilitates collateral ventilation
alveolar interdependence during deep inspiration

Question 5

obstructed region with no collateral ventilation

Answer 5

alveolar gas tensions within area rapidly equilibrate with mixed venous blood.
No more gas exchange
Alveolar gas absorbed - atelectasis develops

Question 6

area of complete obstruction with collateral ventilation

Answer 6

collateral ventilation can prevent atelectasis in the setting of airflow obstruction and they found the gasses that O2 was higher and CO2 was lower than arterial blood without CV

• CV regions of the lungs were still able to carry out useful gas exchange
• CV allows obstructed ares to maintain a useful degrees of function.

Question 7

alveolar interdependence

Answer 7

• collapsing alveolus stretches surrounding alveoli
  alveolus starts to collapse
  collapsing alveolus pulled open
  stretched surrounding alveoli recoil pulling collapsing alveolus open.

when TV is increased, expanding alveoli exert a traction force on the less well expanded alveoli they surround, assisting in re-expansion of collapsed alveoli due to elasticity of surrounding interstitium.

Question 8

Forced Expiratory technique

Answer 8

acc expiratory flow creating high linear velocities that shear mucus from the airway walls
Performed with glottis open - based on EPP theory - equal pressure point
Site of EPP is determined by size of expiratory force, airway stability and elastic recoil.
initiating a forced exp at a low lung volume shifts EPP to periphery targeting secretions in the small airways
initiating a forced expiration from a high lung volume will move EPP centrally

Question 9

EPP theory

Answer 9

rationale behind a huff

the point at which pressure in the bronchi equals peri-bronchial pressure - outside the airways

Question 10

Effective huff

Answer 10

mouth open
forced expiration = mid to low lung volume for peripheral sections
high to mid lung vol for central secretions
Expiration rate varies with individual, disease, degree of airflow obstructions
Peak flow mouthpiece may help

Question 11

ACBT

- steps

Answer 11

breathing control 
3-4 thoracic expansions (+/- insp hold, per, vibe)
breathing control 
3-4 thoracic expansions
(+/- insp hold, perc, vibs)
breathing control 
FET 
breathing control

Question 12

ACBT

• uses
• time

Answer 12

Repeat until huff is dry or patient requires rest
individuals needs
total Rx time - 15-30 mins
can be used with postural drainage, manual clearance techniques,
- percs and vibs

Question 13

Contraindications

Answer 13

Bronchopleural fistula 
lung abcess 
acute pulmonary oedema 
recent lung surgery 
undrained pneumothorax 
CVS instability 
Bullae 
raised ICP / head injury 
Frank haemoptysis