Introduction to Airway Clearance Techniques – Brenda
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AIRWAY CLEARANCE TECHNIQUES TRAINING CLASS WEDNESDAY OCTOBER 30Th 2019 INSTRUCTORS: BRENDA BUTTON MAGGIE MCILWAINE ASSISTANTS: CATHERINE O’MALLEY MELISSA RICHMOND TIMETABLE: 8.00 Introduction 8.15 Cardiopulmonary physiology – Maggie 9.15 Introduction to airway clearance techniques – Brenda 9.45 Coffee Break 10.05 Active Cycle of Breathing Technique – Brenda 10.40 Autogenic Drainage – Maggie 11.30 Practical session 12.00 Lunch 1.00 Use of Positive Expiratory Pressure devices – Maggie 1.45 Oscillating PEP devices - Brenda 2.45 High Frequency chest wall oscillation - Cathy 3.15 Coffee 3.35 Overview of IPV – Cathy 4.00 Practical session. 20 minutes each. Brenda, Cathy, Melissa 5.00 End. 8/1/2019 Airway Clearance Techniques Training class Dr Maggie McIlwaine and Dr Brenda Button Catherine O’Malley Melissa Richmond Objectives • Explain the physiology, and theory behind airway clearance techniques currently used in the treatment of cystic fibrosis. • Demonstrate the airway clearance techniques of Active cycle of breathing techniques, autogenic drainage, PEP, oscillating PEP, HFCWO and IPV. • Compose the scientific evidence supporting the use of each of these techniques. Timetable • 8.00 Introduction: Maggie • 8.15 Cardiopulmonary physiology – Maggie • 9.15 Introduction to airway clearance and breathing techniques – Brenda • 9.45 Coffee break • 10.05 The Active Cycle of Breathing Techniques - Brenda • 10.40 Autogenic Drainage Maggie • 11.30 Practical session • 12.00 Lunch M. McIlwaine 1 8/1/2019 Timetable • 1.00 Use of Positive Expiratory Pressure Devices – Maggie • 1.45 Oscillating PEP Devices – Brenda • 2.45 C High Frequency Chest wall Oscillation (HFCWO) therapy-Coffee • 3.15 Coffee • 3.35 Overview of IPV – Cathy • 4.00 Practical session. 20 minutes each group A) PEP devices – Melissa B) Oscillating PEP devices - Brenda C) HFCWO - Cathy Latest on airway physiology Maggie McIlwaine, PhD, MCSP Associate Clinical Professor, School of Physical Therapy, University of British Columbia Cardiorespiratory Clinical Specialist Physiotherapist Vancouver, BC, Canada. [email protected] GAS TRANSPORT BETWEEN AIR AND TISSUE M. McIlwaine 2 8/1/2019 BIRTH Is not a small adult lung - Alveoli develop from 24 to 300 million by age 8 years. - Tidal volume is large with small inspiratory and expiratory reserve - Elastic fibres in alveoli are immature. - Size of airways proportionally smaller BIRTH - Increased airway resistance with decreased lung compliance. - Little smooth muscle present in airways - Increased number of submucosal glands - Shape of chest is different - Ribs are cartilagenous and horizontal - Positioning and effects on ventilation opposite of adult. M. McIlwaine 3 8/1/2019 BIRTH TO 12 MONTHS - Anterior chest wall opens up as baby extends and develops anti-gravity muscles - Ribs begin to pull downwards by gravity - Intercostal muscles develop - Increasing tidal volume with increased inspiratory and expiratory reserve to support increased activity. M. McIlwaine 4 8/1/2019 EFFECTS OF IMATURE RESPIRATORY SYSTEM ON DISEASE 1. secretions resistance respiratory rate and heart rate as cannot tidal volume to Work of Breathing and early respiratory failure as cannot maximise use of accessory respiratory muscles. I YEAR - 12 YEARS - Increasing tidal volume with decreasing respiratory rate. - Development of collateral ventilation - 5 years, airway resistance to same as adult - 12 years, alveoli complete, elastic fibres in alveoli mature, elongation of chest wall After 25 years • Elastic recoil diminishes • TLC tends to remain static • RV rises • FEV1 and FVC decreases M. McIlwaine 5 8/1/2019 MUCOCILIARY FUNCTION AIRWAYS M. McIlwaine 6 8/1/2019 Respiratory Cilia • Beat with a coordinated beat pattern and frequency (10-14Hz) • 200 cilia per cell, 6 m long, 0.3 m wide • Complex ultrastructure MUCOCILLIARY FUNCTIONS - To act as a mechanical barrier to trap organisms. - Is a chemical screen with anti-oxident properties. - Is a biological barrier. M. McIlwaine 7 8/1/2019 Mucociliary Clearance • Normal cilia Mucus Cilia Epithelium M. McIlwaine 8 8/1/2019 M. McIlwaine 9 8/1/2019 CFTR Mutation Classes I II III IV V Normal synthesis maturation regulation conductance quantity DF508 G551D http://www.umd.be/CFTR/W_CFTR/gene.html Lung Defense: ASL Hydration Mucus Mucus Mucus GelGel PCL Cell PCL Cilia Cilia Tethered PCL MucinsLiquid Cells Microvilli =2 gel model B Button et al. Science 2012;337:937-941 Osmotic coupling of PCL and mucus layers Normal CF Progressive Dehydration Kmucus < KPCL Kmucus = KPCL 30 B Button et al. Science 2012;337:937-941 M. McIlwaine 10 8/1/2019 What does this mean? • CF mucus will be “dehydrated” with elevated osmotic pressures in mucus layers • Beyond a specific osmotic threshold, the PCL gel will deform, mucus will become adherent, and mucus clearance will fail • Reflects a progressive process – Normal early – Heterogeneous distribution of disease – Accumulation of defects = disease progression Mucociliary clearance and obstruction Periciliary Liquid (PCL) Surface CFTR Epithelial Cells normal CF Tenacious Mucus So what’s wrong with the sticky mucus layer? •It becomes a hospitable environment for bacteria to grow leading to infection and inflammation •As well, it physically clogs the airways making it difficult to breathe M. McIlwaine 11 8/1/2019 Bronchiectasis TREATMENT OPTIONS M. McIlwaine 12 8/1/2019 Abnormal airways Bronchospasm Ventolin (salbutamol) Swelling Inhaled steriod Mucus plugging Physiotherapy Pulmozyme Hypertonic saline Infection Antibiotics M. McIlwaine 13 8/1/2019 AIRWAY CLEARANCE TECHNIQUES FOR OBSTRUCTED LUNG DISEASE Cough & Huffing Postural Drainage and percussion (Modified) Active Cycle of Breathing (ACBT) Autogenic Drainage (AD) Positive Expiratory Pressure (PEP) Oscillating PEP High Pressure PEP High Frequency Chest Wall Oscillation (HFCWO) Intra-Pulmonary Percussor Ventilator (IPPV) Eltgol Airway clearance techniques NOT requiring devices ELTGOL M. McIlwaine 14 8/1/2019 Oscillating positive expiratory pressure (PEP) therapy • The Flutter device • The Cornet device • The Acapella device • The Aerobika • The Aerosure • The Flute High Frequency Chest Wall Oscillating Devices Afflo Vest The Vest™ InCourage™ SmartVest® M. McIlwaine 15 8/1/2019 GRAVITY ASSISTED EXPIRATORY VENTILATION AIRFLOW Oscillation ? Two-phase gas liquid flow mechanism -Peak expiratory flow rate (PEFR) -Peak inspiratory flow rate (PIFR) -PEFR needs to be >30-60l/m PEF/PIF needs to be > 1.1 to achieve expiratory airflow. J. Appl Physıology 1987;959-974 FACTORS WHICH AFFECT AIRFLOW - Airway Resistance - Elastic Recoil Pressure - Bronchial Stability - Expiratory Pressure M. McIlwaine 16 8/1/2019 FACTORS WHICH AFFECT AIRFLOW • AIRWAY RESISTANCE – Size of airways Dimensions of the airways FACTORS WHICH AFFECT AIRFLOW • AIRWAY RESISTANCE – Size of airways – Obstruction in airways • Mucus • Swelling • bronchospasm M. McIlwaine 17 8/1/2019 AIRWAY OBSTRUCTION Airway compression and airway obstruction M. McIlwaine 18 8/1/2019 Bronchospasm Ventolin (salbutamol) Swelling Inhaled steriod Mucus plugging Physiotherapy Pulmozyme Hypertonic saline Infection Antibiotics FACTORS WHICH AFFECT AIRFLOW - Airway Resistance - Elastic Recoil Pressure FACTORS WHICH AFFECT AIRFLOW - Airway Resistance - Elastic Recoil Pressure - Bronchial Stability M. McIlwaine 19 8/1/2019 INSPIRATION FORCED EXPIRATION FACTORS WHICH AFFECT AIRFLOW - Airway Resistance - Elastic Recoil Pressure - Bronchial Stability - Expiratory Pressure M. McIlwaine 20 8/1/2019 FORCES AT PLAY IN VENTILATION Mechanism of breathing M. McIlwaine 21 8/1/2019 EPP AND VENTILATION RELATIONSHIPS BETWEEN LUNG VOLUMES M. McIlwaine 22 8/1/2019 OBSTRUCTION OF THE AIRWAYS, NARROWING M. McIlwaine 23 8/1/2019 MEFV CURVE IN HEALTH AND DISEASE ANALYSIS OF FORCED EXPIRATORY MANOEUVRE GRAVITY ASSISTED EXPIRATORY VENTILATION AIRFLOW Oscillation ? M. McIlwaine 24 8/1/2019 VENTILATION ALL airway clearance techniques must include a method of ventilating behind obstructed lung units. -BY - 3 second breath hold - Deep inspiration – interdependence. - Positive expiratory pressure (Collateral ventilation) - Positioning VENTILATION – Breath hold to allow equalization of ventilation across obstructed and non obstructed lung units – Deep breath uses interdependence between lung units – Increasing the expiatory pressure splints the airways open and allows air to move behind secretions by collateral ventilation channels – Positioning to enhance ventilation to obstructed lung units Three second breath hold? Theory A pause allows for “equalisation of ventilation” alters time constants and allows pressure within different lung units to equalise. Studies With multiple-breath nitrogen washout tests, a breath hold resulted in an increase in alveolar gas mixing and a decrease in inhomogeneity (Crawford 1989) M. McIlwaine 25 8/1/2019 INTERDEPENDENCE THEORY:- During inspiration, especially on a deep inspiration, expanding alveoli exert a traction force on adjacent less well expanded alveoli which they surround. It occurs owing to the elasticity of the surrounding interstitium (Mead 1970). CONFIRMED by clinical studies on anesthetised dogs. During normal breathing, collateral ventilation was the primary method of re-expanding collapsed alveoli and that interdependence could only be demonstrated when using high frequency oscillation of between 3-5Hz (Menkes 1972). COLLATERAL VENTILATION PORES OF KOHN First discovered in 1893, confirmed by electron microscope. Each alveoli has 50 pores, usually fluid filled. Opens with large pressure