AIRWAY CLEARANCE Karen Conyers, BSRT, RRT

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

PULMONARY PHYSIOLOGY AND DEVELOPMENT

Birth Respiratory Function Airways Lung compliance 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 Respiratory muscles 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 Changes in respiratory function 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 Hypersecretion of mucus 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

Impaired airway clearance A Vicious Cycle Impaired airway clearance Mucus retention Mucus plugging, obstruction Lung damage Lung infection Inflammation, mucus production

Impaired airway clearance 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

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 PercussiveTech HF 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 May be performed independently 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 Cough IRV VT ERV RV COLLECTING EVACUATING UNSTICKING VT Normal Breathing ERV RV Complete Exhalation

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) Pulmozyme (dornase alfa or DNase) 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 increased work of breathing & frequent coughing increased caloric need Increasing dyspnea decreased caloric intake malnutrition decreased ability to fight infection worsening lung function

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