Karen Conyers, BSRT, RRT AIRWAY CLEARANCE
Karen Conyers, BSRT, RRT
AIRWAY CLEARANCE
Airway Clearance
Pulmonary Physiology and Development
Impaired Airway Clearance
Airway Clearance Techniques
Therapy Adjuncts
PULMONARY PHYSIOLOGY
AND DEVELOPMENT
Birth Respiratory Function
– Terminal respiratory unit not fully developed– Respiratory function performed by alveolar-capillary bed
Airways– Little smooth muscle– Small airway diameter– Increased airway resistance
Lung compliance– Incomplete elastic recoil– Decreased lung compliance
Age 2 Months Alveoli
– 24 million alveoli present – Alveoli small but fully developed– Ability to form new alveoli
Respiratory muscles– Underdeveloped accessory muscles– Diaphragm is primary muscle of respiration
Response to increased ventilatory demands– Respiratory rate increases, not tidal volume
Ages 3 to 9 Months
Increasing strength– Baby learns to hold head up, reach for things– Upper body strength develops, including accessory
muscles for respiration Changes in respiratory function
– Learns to sit up: rib cage lengthens – Greater chest excursion– Increased tidal volume
Age 4 Years
Lung development– Development of pre-acinar
bronchioles and collateral ventilation (pores of Kohn)
– Development of airway smooth muscle
Age 8 Years
Continued lung development– Alveolar development complete – Alveolar size increases– Total lung volume increases – 300 million alveoli (increased from 24 million
at age 2 months)
Adult Lung
Gradual loss of volume Loss of elasticity
– Decreasing compliance
Environmental effects– Smoking– Air pollution– Occupational hazards
Disease effects
Factors Affecting Airflow
Airway resistance
Turbulent airflow
Airway obstruction
Normal Airway Resistance Decreasing cross-sectional area from acinus to
trachea causes increased resistance, as airflow moves from small to large airways.
Cross-sectional areas:– trachea diameter 2 cm– 4th generation bronchi 20 cm– bronchioles 80 cm– acinus cross-section 400 cm
Greatest airway resistance in large airways; laminar
airflow in small airways
Airway Obstruction
Increased airway resistance– Bronchospasm– Inflammation
Hypersecretion of mucus– Acute process– Chronic disorder
Mucus
Mucus produced by goblet cells in airway
Chronic airway irritation increased numbers
of goblet cells larger quantities of mucus
Cilia move together in coordinated fashion to move
mucus up airways
IMPAIRED
AIRWAY CLEARANCE
Impaired Airway Clearance: Factors
Ineffective mucociliary clearance Excessive secretions Thick secretions Ineffective cough Restrictive lung disease Immobility / inadequate exercise Dysphagia / aspiration / gastroesophageal reflux
Results of Impaired Airway Clearance
Airway obstruction
Mucus plugging
Atelectasis
Impaired gas exchange
Infection
Inflammation
A Vicious Cycle
Entering the Cycle
ASPIRATION
ASTHMA
ASPERGILLOSIS
CYSTICFIBROSISGASTRO-
ESOPHAGEALREFLUX
PRIMARYCILIARY
DYSKINESIA
NEURO-MUSCULARWEAKNESS
AIRWAY CLEARANCE
TECHNIQUES
Airway Clearance Techniques
Goals
Conventional Methods
Newer Therapies
Therapy Adjuncts
Goals
Interrupt cycle of lung tissue destruction
Decrease infection and illness
Improve quality of life
Conventional methods
Cough
Chest Physiotherapy
Exercise
Cough
Natural response
Only partially effective
Frequent coughing leads to “floppy” airways
May be suppressed by patient
Chest Physiotherapy (CPT)
Can be used with infants Requires caregiver participation Technique dependent Time consuming Physically demanding Requires patient tolerance Effectiveness debated
Exercise
Recommended for most patients Pulmonary rehabilitation expectation Training
– Ability to exercise related more to muscle mass than to pulmonary function
– Improves oxygen uptake by muscle cells
Many patients limited by physical disability
Newer Therapies
PEP valve Flutter In-Exsufflator HFCWO (Vest) Intrapulmonary percussive ventilation (IPV) Cornet PercussiveTech HF
PEP valve
Positive Expiratory Pressure Action: splints airways during exhalation Can be used with aerosolized medications Technique dependent Portable Time required: 10 - 15 minutes
Flutter
Action: loosens mucus through expiratory oscillation; positive expiratory pressure splints airways
Used independently Technique dependent Portable May not be effective at low airflows Time required: 10 - 15 minutes
In-Exsufflator
Action: creates mechanical “cough” through the use of high flows at positive and negative pressures
Positive/negative pressures up to 60 cm of water Used independently or with caregiver assistance Technique independent Portable
ABI Vest (HFCWO) Action: applies High Frequency Chest Wall Oscillation
to entire thorax; moves mucus from peripheral to central airways
Used independently or with minimal caregiver supervision
May be used with aerosolized medications Technique independent Portable Time required: 15-30 minutes
Intrapulmonary Percussive Ventilation (IPV)
Action: “percussion” on inspiration, passive expiration; dense, small particle aerosol
Used independently or with caregiver supervision
Used with aerosolized meds Technique dependent May not be well tolerated by patient Time required: 20 minutes
Other devices
Cornet– Similar to action of Flutter– Lower cost, disposable
PercussiveTech HF– Hand-held device used with aerosol meds– Similar to action of IPV– Requires 50 PSI gas source
European / Canadian Techniques
Huff cough (forced expiratory technique)
Active Cycle of Breathing Technique (ACBT)
Autogenic Drainage
Forced Expiratory Technique
“Huff” cough– Three second breath hold – Open glottis– Prevents airway collapse– Effective technique for “floppy” airways– Easy to learn
Active Cycle of Breathing Technique
Three steps: – Breathing control– Thoracic expansion / breath hold– Forced expiratory technique
May be performed independently Easily tolerated
Autogenic Drainage
Three phases– Unsticking– Collecting– Evacuating
May be performed independently Harder to teach and to learn than other techniques May be difficult for very sick patients to perform
Autogenic Drainage
NormalBreathing
CompleteExhalation
VT
RV
ERV
IRV
Cough
UNSTICKING COLLECTING EVACUATING
THERAPY
ADJUNCTS
Therapy Adjuncts
Antibiotics
Bronchodilators
Anti-inflammatory drugs
Mucolytics
Nutrition
Antibiotics
Oral Intravenous Nebulized
– Aminoglycosides: P. aeruginosa Gentamycin: 40-80 mg Tobramycin: 40-120 mg Tobi: 300 mg per dose: high dose inhibits mutation of
P. aeruginosa in lung
Bronchodilators
Hyperreactive airways common in many
pulmonary conditions
Albuterol, Atrovent
MDI or nebulized
Administered prior to other therapies
Mucolytics
Mucomyst (acetylcysteine)– Breaks disulfide bonds– Airway irritant
Pulmozyme (dornase alfa or DNase)– Targets extracellular DNA in sputum– Specifically developed for cystic fibrosis
Hypertonic saline– Sputum induction– Australian studies
Anti-inflammatory Drugs
Inhaled steroids via metered dose inhaler
Oral or IV prednisone
High-dose ibuprofen (cystic fibrosis)
Nutrition
Connection between nutrition and lung function!
Worsening lung function Worsening lung function increased work of
breathing & frequent coughing increased
caloric need
Increasing dyspnea decreased caloric intake
malnutrition decreased ability to fight
infection worsening lung functionworsening lung function
Interrupting the Vicious Cycle
ANTIBIOTICSANTI -
INFLAMMATORIES
AIRWAYCLEARANCETECHNIQUES
MUCOLYTICS
BRONCHODILATORS
NUTRITION