Autogenic drainage Flashcards
Autogenic drainage
autogenic = self generated
- self drainage
Utilises gentle breathing at different lung volumes to loosen, mobilise and clear bronchial secretions
physiology
Airway clearance techniques (ACTs) supplement the body’s muco-ciliary clearance (MCC) system when it is impaired
MCC system important lung defense mechanism
airway surface liquid comprising mucus and periciliary layers (PCLs)
ciliary epithelium
cough clearing mechanisms
Healthy people, cilia beat at a mean frequency of 11–13 Hz, propelling mucus proximally up the airways at a rate of 4– 5 mm·min-1
Rate of clearance influenced by
hydration state
rigidity and viscosity of mucus
MCC system is impaired in chronic suppurative lung diseases e.g. cystic fibrosis (CF), primary ciliary dyskinesia (PCD) and non-CF bronchiectasis
→due to the occurrence of one or more;
-dehydration of the PCL
-absence of lubricant activity → prevents adhesion of mucus to airway surfaces
-defect within the cilia
-certain immunodeficiencies
If this system is breached, the lung is more susceptible to infection and inflammation which can lead to further airway damage and eventually bronchiectasis
ACTs should assist natural muco-ciliary clearance system to transport secretions proximally up the airways
Historically, to achieve muco-ciliary clearance, postural drainage positions were used primarily for drainage by relying on gravity e.g. ‘ketchup bottle method’
Newer ACTs rely on 2 overriding physiological principles
Mechanism to allow air to move behind obstruction and ventilate the regions distally → EFFECTIVE VENTILATION
AND
2. Modification of expiratory airflow to propel secretions proximally up the airways → EFFECTIVE EXPIRATORY AIRFLOW
Aim of A.D
To mobilise secretions from the bronchial walls and transport them from the peripheral to the central airways
By …
Achieving the highest possible airflow, keeping bronchial resistance low and avoiding bronchospasm and dynamic airway collapse
before starting
Clear the upper airways by blowing the nose or, if necessary, using a nasal spray or sinus rinse
If prescribed, take bronchodilators +/-mucolytics +/-airway hydrators inhaled therapies beforehand
positioning
Start in the upright position with patients new to AD
Can be completed in any position e.g. side-lying, semi-recombinant, supine
NB - think about effect positioning has on ventilation
optimal positioning for secretion clearance
secretions upper lobe - supine, side lying
secretions in middle lobe and lingula upright, side lying or supine
secretions in right lung - adults: right-side lying (adults)
left side lying - children
secretions in left lung: left side lying - adults
right side lying - children
secretion in lower lobes - upright/ side lying
Inspiration
Slow breath in through the nose Nasal inspiration stimulates diaphragm Warms and humidifies the airways Reduces turbulent airflow Allows for even filling
Breath should be larger than VT
Up to twice size VT
Followed by 3 second breath PAUSE
Facilitates collateral ventilation
More time for obstructed areas to fill
With an open glottis
Some patients may need to breathe in through their mouth, with or without the assistance of a piece of wide tubing (can also be used for huffing/FETs)
Expiration
Breathe out with upper airways (glottis and throat) open AND relaxed, down toward expiratory reserve volume (ERV)
Known as searching breathe
Expiration via nose is preferable but many patients prefer the mouth as it enhances the auditory feedback
Use cardboard tube to further enhance auditory feedback
The expiratory force must be controlled → expiratory airflow reaches the highest possible velocity without causing early airway compression
Patients with dynamic airway collapse may only need to breathe out with a relaxed sigh
Less advanced disease may need an expiratiory force which closely resembles an FET/huff
Lung volumes
Start with low-volume breaths, from ERV
Repeat VT breaths (in and out) until secretions are felt or heard gathering in the airways - will take a few breaths
Once the secretions are heard ‘crackling’ start of the expiration, take slightly larger inspiration and repeat and repeat … like an escalator!
When the collected secretions reach the upper airways they should be cleared by a high-volume FET +/-cough
At all stages, the patient must be encouraged to suppress their cough until the secretions are in the central airways and ready to be easily expectorated
Phases of A.D
mobility collect evacuate
AD should not be thought of as 3 entirely separate phases, but as if the secretions were being transported continuously on a ‘conveyor belt’ or ‘like an escalator’
Teaching AD
Teach ‘AD Breathe’ → ’sigh’ ‘hot steamy breathe’ on expiration
Mouth and glottis open
Can use tissue to help
Cardboard mouthpiece also helpful
Or combination both!
Listen for high pitched sound/wheeze, should be avoided
Listen for secretions ‘crackling’ sound when do they start? End, mid vs start exp? fine vs coarse? quiet vs loud?
Palpate chest wall for crackles
therapist and patient to aid tactile feedback
Explain and practice low, mid and high lung volumes and sensation for each
‘Listen and feel’ for crackles
Explain why cough must be avoided until instructed
If targeting periphery it closes airways
Teach good cough = 1-2 coughs (as strong as possible) with head up trying to project airflow forwards and up
Decreases air resistance and avoids small repetitive coughs
Prescription
Should be individualized – not a recipe!
NB timing with inhaled therapies, exercise, feed/meals
Duration and number of the AD sessions depends on multiple factors
Volume, purulence of secretions, fatigue, work of breathing – all patients are different!
AD can be used as sole method ACT or combined with other adjuncts e.g. PEP, BiPAP
advantages disadvantages
Complete independently
Free
No equipment required
Gentle technique, should be less tiring/effortful
Difficult to teach/learn
Need patience - clinician and pt
Need good exp airflow
Need moderate amounts secretions = auditory, tactile and proprioceptive feedback
Not suitable for younger children e.g. younger than 8 years
Assisted autogenic drainage
Used in infants, noncooperative patients, more severe disease/difficulty with regular AD or can be helpful when learning AD
Use hands/belt
Patience is a must
A.A.D
During expiration, gently follow the patients breathe to the desired level
Hands gradually restrict the inspiration to stimulate the patient to exhale slightly more than the previous breathing cycle
Gentle increase of manual pressure on the chest during each inspiration is performed in order to guide patient towards the desired lung volume level
No thoracic compression or excessive force
Feedback plays a key-roll, feeling or hearing the secretions move while avoiding any early or abnormal airway compression or closure
Wait for the spontaneous cough or encourage high volume FET
