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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 Terminal respiratory unit not fully developed
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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 • 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 Impaired airway clearance Mucus retention Mucus plugging, obstruction Lung damage Lung infection Inflammation, mucus production
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 • 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 Cough IRV 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) • 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 ANTI - INFLAMMATORIES ANTIBIOTICS Inflammation, mucus production