Karen Conyers, BSRT, RRT

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AIRWAY CLEARANCE

• Karen Conyers, BSRT, RRT

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Airway Clearance

• Pulmonary Physiology and Development
• Impaired Airway Clearance
• Airway Clearance Techniques
• Therapy Adjuncts

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• PULMONARY PHYSIOLOGY
• AND DEVELOPMENT

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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

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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

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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

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Age 4 Years

• Lung development
• Development of pre-acinar bronchioles and
  collateral ventilation (pores of Kohn)
• Development of airway smooth muscle

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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)

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Adult Lung

• Gradual loss of volume
• Loss of elasticity
• Decreasing compliance
• Environmental effects
• Smoking
• Air pollution
• Occupational hazards
• Disease effects

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Factors Affecting Airflow

• Airway resistance
• Turbulent airflow
• Airway obstruction

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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

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Airway Obstruction

• Increased airway resistance
• Bronchospasm
• Inflammation
• Hypersecretion of mucus
• Acute process
• Chronic disorder

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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

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• IMPAIRED
• AIRWAY CLEARANCE

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Impaired Airway Clearance Factors

• Ineffective mucociliary clearance
• Excessive secretions
• Thick secretions
• Ineffective cough
• Restrictive lung disease
• Immobility / inadequate exercise
• Dysphagia / aspiration / gastroesophageal reflux

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Results of Impaired Airway Clearance

• Airway obstruction
• Mucus plugging
• Atelectasis
• Impaired gas exchange
• Infection
• Inflammation

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A Vicious Cycle
Impaired airway clearance
Mucus retention
Mucus plugging, obstruction
Lung infection
Lung damage
Inflammation, mucus production
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Entering the Cycle
ASTHMA
NEURO- MUSCULAR WEAKNESS
Impaired airway clearance
PRIMARY CILIARY DYSKINESIA
Mucus Retention
Mucus plugging, Obstruction
ASPIRATION
Lung Infection
Lung Damage
CYSTIC FIBROSIS
GASTRO- ESOPHAGEAL REFLUX
Inflammation, Mucus production
ASPERGILLOSIS
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• AIRWAY CLEARANCE
• TECHNIQUES

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Airway Clearance Techniques

• Goals
• Conventional Methods
• Newer Therapies
• Therapy Adjuncts

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Goals

• Interrupt cycle of lung tissue destruction
• Decrease infection and illness
• Improve quality of life

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Conventional methods

• Cough
• Chest Physiotherapy
• Exercise

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Cough

• Natural response
• Only partially effective
• Frequent coughing leads to floppy airways
• May be suppressed by patient

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Chest Physiotherapy (CPT)

• Can be used with infants
• Requires caregiver participation
• Technique dependent
• Time consuming
• Physically demanding
• Requires patient tolerance
• Effectiveness debated

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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

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Newer Therapies

• PEP valve
• Flutter
• In-Exsufflator
• HFCWO (Vest)
• Intrapulmonary percussive ventilation (IPV)
• Cornet
• PercussiveTech HF

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PEP valve

• Positive Expiratory Pressure
• Action splints airways during exhalation
• Can be used with aerosolized medications
• Technique dependent
• Portable
• Time required 10 - 15 minutes

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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

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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

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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

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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

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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

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European / Canadian Techniques

• Huff cough (forced expiratory technique)
• Active Cycle of Breathing Technique (ACBT)
• Autogenic Drainage

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Forced Expiratory Technique

• Huff cough
• Three second breath hold
• Open glottis
• Prevents airway collapse
• Effective technique for floppy airways
• Easy to learn

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Active Cycle of Breathing Technique

• Three steps
• Breathing control
• Thoracic expansion / breath hold
• Forced expiratory technique
• May be performed independently
• Easily tolerated

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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

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Autogenic Drainage
Cough
IRV
COLLECTING
EVACUATING
UNSTICKING
VT
Normal Breathing
ERV
Complete Exhalation
RV
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• THERAPY
• ADJUNCTS

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Therapy Adjuncts

• Antibiotics
• Bronchodilators
• Anti-inflammatory drugs
• Mucolytics
• Nutrition

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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

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Bronchodilators

• Hyperreactive airways common in many pulmonary
  conditions
• Albuterol, Atrovent
• MDI or nebulized
• Administered prior to other therapies

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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

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Anti-inflammatory Drugs

• Inhaled steroids via metered dose inhaler
• Oral or IV prednisone
• High-dose ibuprofen (cystic fibrosis)

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Nutrition

• Connection between nutrition and 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 function

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Interrupting the Vicious Cycle
Impaired airway clearance
NUTRITION
MUCOLYTICS
Mucus plugging, obstruction
Mucus retention
AIRWAY CLEARANCE TECHNIQUES
BRONCHODILATORS
Lung Damage
Lung infection
ANTIBIOTICS
ANTI - INFLAMMATORIES
Inflammation, mucus production