Introduction to Airway Clearance Techniques

Home , Airway clearance therapy, Chest physiotherapy, Tidal volume

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

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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

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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.

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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.

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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

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MUCOCILIARY FUNCTION

AIRWAYS

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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.

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Mucociliary Clearance

• Normal cilia

Mucus

Cilia

Epithelium

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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

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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

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Bronchiectasis

TREATMENT OPTIONS

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Abnormal airways

Bronchospasm

Ventolin (salbutamol) Swelling Inhaled steriod

Mucus plugging Physiotherapy Pulmozyme Hypertonic saline

Infection Antibiotics

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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

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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®

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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

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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

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AIRWAY OBSTRUCTION

Airway compression and airway obstruction

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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

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INSPIRATION FORCED EXPIRATION

FACTORS WHICH AFFECT AIRFLOW

- Airway Resistance

- Elastic Recoil Pressure

- Bronchial Stability

- Expiratory Pressure

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FORCES AT PLAY IN VENTILATION

Mechanism of breathing

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EPP AND VENTILATION

RELATIONSHIPS BETWEEN LUNG VOLUMES

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OBSTRUCTION OF THE AIRWAYS, NARROWING

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MEFV CURVE IN HEALTH AND DISEASE

ANALYSIS OF FORCED EXPIRATORY MANOEUVRE

GRAVITY ASSISTED

EXPIRATORY VENTILATION AIRFLOW

Oscillation ?

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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)

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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 gradients (Blackstacky 1992)

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COLLATERAL VENTILATION

Canal of Lambert Connections between distal bronchioles Found to exist by Lambert 1955 Pathways of Martin Clinical studies on excised dogs lungs showed that when lungs were pressurised to between 17 – 28 cms H2O, aerosolised ink was found to have moved between respiratory bronchioles and terminal bronchioles from adjacent lung segments

VENTILATION, PERFUSION AND POSITIONING Brenda will discuss this

Optimal positioning for airway clearance techniques to enhance ventilation to obstructed regions of the lung Alternative, 2nd choice, Optimal position Position Secretions in upper Supine Side Lying lobes Secretions in right Upright Side Lying or Supine middle section and left lingual Secretions in right Adults: place in right side lung lying Children: place in left side lying Secretions in left Adults: place in left side lung lying Children: place in right side lying Secretions lower Upright Side Lying lobes

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Introduction to modern airway clearance therapy Dr Brenda M. Button Adjunct Clinical Associate Professor Dept. of Respiratory Medicine The Alfred Hospital Monash University Melbourne, Victoria, Australia [email protected]

Last century: conventional physiotherapy; chest PT; CPT • Postural drainage & percussion (clapping) • Head down tilted positions • Patients dependent on a therapist / assistant • Technique did not allow independence • Had to wait for the person -  adherence • Uncomfortable-  adherence • Person with CF – ‘medicalized’ • Self image that of a sick person / patient • Life not at all ‘normal’ • Tended to not pursue a normal life

Retrograde movement of stomach contents into the esophagus

Physiological versus pathological reflux (more episodes that take longer to clear  inflammation & dysfunction)

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GER & the lung

Barish et al 1985

Pulmonary aspiration Reflex bronchospasm Mechanisms:  esophageal tone Inappropriate relaxations of theo esophageal sphincter Pathological GER

Side effects with head down tilted PD &P • Hypoxemia (2 papers) • Desaturation Mc Donnell 1986, Falk 1984 • Headaches and sinus pain Cecins et al 1999 • Rib fractures – pre-term infants / osteoporosis Purohit 1975 • Potential for harm Hess Respiratory Care 2001

• GER: - pre-term infants Newell 1987 - infants and children Vandenplas 1991 - infants and children with CF Foster et al 1983 - children with CF Scott 1985 - infants with CF Button 1997, 2003 - children, adolescents & young adults Button1998 - CF infants Constantini 2001 - COPD & Bronchiectasis Mokhlesi et al 2001; Lee et al 2014

Standard PT=SPT • 20 infants • RCT: each regimen repeated 2X over 2 days • Positions randomized • Physiotherapy • 4X8mins – each position – 2mins rest between each position Mean age Modified PT= MPT 2.2 months 11 / 20 (55%) with mild, moderate or severe GER Significantly more infections & ABs needed in first 12 months in SPT group

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Longer term study: RCT Button et al 2003 Brasfield scores - CXR: MPT - SPT

p=0.028* Normal

Longer term study: RCT Lung function - SPT versus MPT 5 to 6 years Button et al 2003

FVC FEV1 FEF25-75

GER during PD: 3 – 18 years Button et al 1998

30° head down tilt

Black bars = during postural drainage White bars = background

Mean number episodes / hr PD 3.8±2.95 vs BG 0.9±0.68; p<0.0001

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PD to PEP in upright sitting in CF Button et al 1998

 Annual hospital bed days: - PD year mean 105 days (87-135) - PEP year: 36 days (9-83) 215 fewer days in PEP year p<0.0005  in symptoms using PEP p<0.001

 FEV1 & FVC - p<0.001  with PEP

Results: reflux episodes in individual positions

Symptomatic & silent GER in CF adults silent No symptoms does not = no reflux symptomatic ……normal value

100 200 375

80 160 300

60 120 225

40 80 150

20 40 75

0 0 0 DeMeester Score Proximal reflux Distal reflux (Normal <14.72) episodes /24hr episodes /24hr ……normal value n=35 adults with CF Button et al, 2006

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Provocation of episodes of GER with PD • Head down tilted positions  esophageal acid exposure  regional blood flow - prostaglandin E2  inflammation - dysfunction of vagal nerve   LES pressure  inappropriate relaxations of LES - dysmotility  vicious cycle of events favouring GER  esophagitis

• Repeated CPT sessions may  trigger vicious cycle & pathological reflux leading to increasing pulmonary disease Vandenplas et al 1991

GER and Yoga

• 20 minute episode of GER at end of session

• Head down tilted positions  reflux episodes  inflammation of LES & esophagitis  inappropriate relaxations of the LES  vicious cycle Vandenplas 1991

Head down positions may trigger this vicious cycle

Minimizing GER • Avoid activities that  intra-abdominal pressure: - paroxysms of coughing - slumped sitting postures (including infants) - ACT straight after meals (full stomach) • ACT before meals or at least 2-3 hours after meals • Avoid eating before lying down with a full stomach • Avoid foods that reduce lower esophageal sphincter pressure: caffeine, chocolate, peppermint etc. • Raise head of bed 15-20° for sleeping • ACT in supported upright sitting or horizontal positions • Avoid head down tilted positions & activities • Avoid vomiting  inhaled noxious gases with inspiration after vomiting- avoid paroxysms of coughing vomiting can become habitual

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Ventilation is favoured in the lowermost lung fields, regardless of body position • The causes of regional differences in ventilation - anatomy of the lung Top of lung - mechanics of breathing -10cmH2O • Upright position - intrapleural pressure more negative at the top of lung → becomes progressively less negative towards bottom of lung -2cmH2O • Weight of the suspended lung Intra-pleural • Greater ventilation in lowermost Pressure regions – gravitational effects West JB 1985

Upright versus alternate side lying

Mark Elkins graphics

Greatest ventilation in most dependent (lowermost) regions

clearance from dependent lung 15º head down left side postural drainage  change of practice Lannefors 1992, Martins 2012

Effects of ELTGOL in chronic bronchitis

• ELTGOL – slow expiration with glottis open in lateral positions • “L’expiration lente totale glotter ouverte en infralateral” • Stable mild – moderate chronic bronchitis - R lateral position • 12 patients 45-75 yrs • Significant increase in mucus clearance from periphery of the dependent lung Martins JA et al 2012

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Huff and cough strength in healthy, COPD & CF Badr, Elkins et al 2002 ; Elkins, Alison & Bye 2005 In order of most strength: MEP significantly  - side-lying • Standing - head-down tilt position • Chair sitting feet on floor • Sitting in bed PEFRs significantly  backrest vertical - three-quarters sitting - supine • Sitting in bed backrest: 45º - side-lying - head-down positions • Supine

• Side lying Reflux scores & oxygenation: • Side lying: head down 20º - worst in head down positions

Position during airway clearance therapy • Scientific rationale

• Upright supported sitting

• Limit proximal spread of refluxate • Avoid slumped sitting  GER Orenstein 1983

• Horizontal positioning = postural drainage in CF & non-CF bronchiectasis ~ sputum expectorated: significantly fewer side effects Cecins et al 1999

• Horizontal  head up in patients with GER

• Changing from head down to horizontal

• Discomfort / pain - listen to the patient

Stress urinary incontinence

• Adult CF women - urinary incontinence 38-64% depending on lung symptom severity Cornacchia et al 1999, White 2000, Davis 2000, Button et al 2003 • Adult COPD women -urinary incontinence - 66% Jones 1997 • Adult men: - CF 18-50 years 15% vs 7.5% controls - COPD 50 -70 years 39% vs 17% “ Burge, Button et al 2011

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Urinary incontinence & lung disease

• Stress urinary incontinence more common in women & men with bronchiectasis, COPD & CF • Related to lung disease and cough:  pressure on pelvic floor • Particularly problematic with acute exacerbations & pelvic floor muscle fatigue • Screen for UI – respiratory clinic visits – women & men • Respiratory physiotherapist provide basic treatment for women • Refer to continence therapist (men) - if problems continue (women) after prescribing Pelvic Floor Muscle Training (PFMT)

Pelvic floor muscle training in women • Type 1 fibres: “Pull up and hold for 3 – 5 seconds” • Type 2 fibres: Superimpose burst of activity on contracting muscle: “Pull up, up, up as high as you can” • Dosage: - 3 sets of 10 with rests in one session or - a set of 1 X 10 three times per day if unable to complete the above

ACT & continence in women

• The teaching of a contraction of the pelvic floor, "the knack", prior to coughing, huffing, sneezing and all activities that apply pressure to the pelvic floor Miller et al 1996

• Endurance training of pelvic floor muscles to meet the demands of huffing and coughing

• Optimal positioning during airway clearance therapy that maximizes control of the bladder via the pelvic floor - maintain normal lumbar lordosis rather than lumbar flexion Sapsford, 2001

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Outcome measures to optimize ACT • Lung function tests: lab & portable spirometers • Sputum volume / quality • Cough / cry - frequency / sound • Auscultation • Oximetry - SpO2 / heart rate • Radiology – CXR, CT scans • ABGs • Exercise tolerance / capacity • Dyspnea measures – VAS / BORG scores of breathlessness • Respiratory rate • Basal expansion • Sleep quality – lack of coughing, congestion, secretions • Days on antibiotics – days in hospital • Exacerbation rate • QOL measures n=1 studies

Huffing – breathing control

• Forced expirations – forced expiratory maneuvers • Used with all airway clearance techniques • Combination of 2-3 forced expirations (huffs) and periods of breathing control • Huffs from low lung volumes mobilize secretions in small peripheral airways • Huffs from mid lung volumes - mid airways (a/w) • Huffs from high lung volumes – large upper a/w • Produces supra-maximal air flow and high linear velocities • ‘Forced expiratory maneuvers are probably the most effective part of chest physiotherapy’ Van Der Schans 1997

Huffing

• Increased expiratory airflow • Air flows faster out through the airways than in • Shear forces – loosen mucus off the airway • Erosion of mucus from the airway wall • Pulls mucus towards the upper airway • Like wind blowing over the bay - light wind – water stays flat and calm - strong wind pulls the water up into white caps = pulling mucus off the airway wall – “velcro effect”

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Effective huffing

• Open mouth • Open glottis (throat) • Increased airflow comes from the belly - diaphragm - contraction of the abdominal muscles • Modulated airflow • Avoiding dynamic airway collapse from too much force • Low, mid and high lung volumes • Move secretions from the periphery to the mouth

Huffing - forced expirations – equal pressure point theory - EPP

Physiotherapy for respiratory disease: 21st century 1. Modern Airway Clearance Therapy ACT: individualized • Active cycle of breathing • Autogenic drainage • Positive expiratory pressure - PEP • Oscillating PEP - OscPEP • Intra-pulmonary percussive ventilation – IPV • High frequency chest wall oscillation - HFCWO • Huffing with all techniques • Cough: when ready 2. Adjunctive inhaled mucolytic therapies 3. Physical exercise: normal muscle & joint strength & mobility; endorphins; immune properties; better sleep & appetite; normal postural alignment; exercise as ACT Dwyer et al 2011

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Postural drainage & side effects

• Button BM,Heine RG, Catto-Smith AG, Phelan PD,Olinsky A. Postural drainage and gastrooesophageal reflux in infants with cystic fibrosis. Arch Dis Childhood 1997;76:148- 50. • Button BM, Heine RG, Catto-Smith AG, Olinsky A, Phelan PD, Ditchfield MR, Story I • Chest physiotherapy in infants with cystic fibrosis: to tip or not? A five-year study. Pediatr Pulmonol. 2003;35(3):208-13. • Cecins, N., et al., The active cycle of breathing techniques - to tip or not to tip? Respir Med, 1999; 93: 660-665. • Desmond KJ, Schwenk WF, Thomas E, Beaudry PH, Coates AL. Immediate and long-term • effects of chest physiotherapy in patients with cystic fibrosis. J Pediatr 1983;103:538-42. • Matthews LW, Doershuk CF, Wise M, Eddy G, Nudelman H, Spector S. A – therapeutic • regimen for patients with cystic fibrosis. J Pediatr 1964;65:558-75. • McDonnell T, McNicholas WT, Fitzgerald MX. Hypoxemia during chest physiotherapy in • patients with cystic fibrosis. Irish J Med Sci 1986;155:345-8. • Passero MA, Remor B, Salomon J. Patient reported compliance with cystic fibrosis therapy. Clin Pediatr 1981;20:264-6. • Purohit DM, Caldwell C, Levkoff AH. Letter: Multiple rib fractures due to physiotherapy in a neonate with hyaline membrane disease. American journal of diseases of children (1960). 1975 Sep;129(9):1103-4. • Reisman JJ, Rivington-Law B, Corey M,Marcotte J,Wannamaker E,Harcourt D, et al. Role of conventional physiotherapy in cystic fibrosis. J Pediatr 1988;113:632-636.

Gastro-oesophageal reflux • Bendig DW, Seilheimer DK, Wagner ML, Ferry GD, Harrison GM. Complications of gastroesophageal reflux in patients with cystic fibrosis. J Pediatr 1982; 100: 536-540. • Button BM, Heine RG, Catto-Smith A, Phelan PD, Olinsky A. Postural drainage and gastro- oesophageal reflux in infants with cystic fibrosis. Arch Dis Child 1997; 76: 148-150. • Button BM, Heine RG, Catto-Smith AG, Phelan PD. Postural drainage in cystic fibrosis: is there a link with gastro-oesophageal reflux? J Paediatr Child Health 1998;34: 330-334 • Button BM, Heine RG, Catto-Smith AG, Olinsky A, Phelan PD, Ditchfield MR, Story Chest physiotherapy in infants with cystic fibrosis: to tip or not? A five-year study. Pediatric Pulmonology 2003;35:208-213. • Button BM. Postural drainage techniques and gastro-oesophageal reflux in infants with cystic fibrosis. Letter to the Editor. European Respiratory Journal 1999; Vol.14; 6: 1456. • Button BM, Heine RG, Catto-Smith AG, Phelan PD, Olinsky A. Chest physiotherapy, gastro- oesophageal reflux, and arousal in infants with cystic fibrosis. Arch Dis Child 2004;89:435-439. • Button BM, Roberts S, Kotsimbos T, Levvey B, Williams T, Bailey M, Snell G, Wilson JW. Gastroesophageal reflux (symptomatic and silent): a potentially significant problem in patients with cystic fibrosis before and after lung transplantation. Journal of Heart and Lung Transplantation 2005;24:10:1522-29. • Burton P, Button B, Lee M, Roberts A, Levvey B, Smith A, Brown W, Snell G. • Longer Term Outcomes of Laproscopic Fundoplication in Patients after Lung Transplant The Journal of Heart and Lung Transplantation, 2009 Volume 27, Issue 2, Pages S126-S126. • Burton P, Button B, W. Brown, M. Lee, S. Roberts, S. Hassen, M. Bailey, A. Smith, G. Snell Medium-term outcome of fundoplication after lung transplantation (p ). Published Online: Jun 9 2009 1:20PM. DOI: 10.1111/j.1442-2050.2009.00980.x • Burton PR, Button B, Brown W, Lee M, Roberst S, Hassen S, Bailey M, Smith A, Snell G. Medium- term outcome of fundoplication after lung transplantation. Diseases of the Esophagus 2009: 22: 642-648

• Carlsson R, Dent J, Bolling-Sternevald E, Johnsson F, Junghard O, Lauritsen K, Riley S, Lundell L. The usefulness of a structured questionnaire in the assessment of symptomatic gastro-oesophageal reflux disease. Scan J Gastroenterol 1998;33 (10): 1023-1029. • Davidson AGF. Gastrointestinal and pancreatic disease in CF. In: Cystic Fibrosis 2nd Edition. Hodson ME and Geddes DM (eds). London, Arnold. 2000;12;261-28. • Davis RD, Lau CI, Eubanks S et al. Improved lung allograft function following fundoplication in lung transplant patients with gastroesophageal disease undergoing lung transplantation. J Thorac Cardiovasc Surg 2003;125:533-542. • DeMeester TR, Wernly JA, Little AG, Bermudez G, Skinner DB, Wang C-I, Pellegrini CA, Klementschitsch, Johnson LF. Technique, indications, and clinical use of 24 hour esophageal pH monitoring. J Thorac Cardiovasc Surg 1980; 79: 656-670. • DeMeester TR. Prolonged oesophageal pH monitoring. In Gastrointestinal motility: which test? NW Read (Ed). Wrightson Biomedincal Publishing Ltd. 1989. • Dobhan R and Castell Donald. Normal and abnormal proximal esophageal acid exposure: results of ambulatory dual-probe pH monitoring. Am J Gastroenterol 1993; Vol. 88;1:25-29 • Doumit M et al. Acid and non-acid reflux during physiotherapy in young children with cystic fibrosis. Pediatric Pulmonology 2012; 47:119-124. • Feigelson J, Girault F, Pecau Y. Gastro-oesophageal reflux and esophagitis in cystic fibrosis. Acta Paediatr Scand 1987; 76: 989-990. • Foster AC, Voyles JB, Murphy SA. Twenty four hour pH monitoring in children with cystic fibrosis: association of chest physiotherapy to gastro-esophageal reflux. Paediatr Res 1983; 17: 188A • Hassall E, Israel DM, Davidson ADF, Wong LTK. Barrett’s Esophagus in Children with cystic fibrosis: not a co-incidental association. American Journal of Gastroenterology 1993; Vol. 88 (11): 1934-1938

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• Howard PJ, Maher L, Pryde A, Heading RC. Symptomatic gastro-oesophageal reflux, abnormal oesophageal acid exposure, and mucosal acid sensitivity are three separate, though related, aspects of gastro- oesophageal reflux disease. Gut 1991; 32: 128-132. • Ing AJ, Ngu MC, Breslin AB. Pathogenesis of chronic persistent cough associated with gastroesophageal reflux. Am J Respir Crit Care Med 1994; 149:160-167. • Lannefors L, Button BM, & McIlwaine M. Physiotherapy for infants and young children with cystic fibrosis: current practice and further developments. J R Soc Med. 2004; 97 (suppl.44): 8-25 • Lee AL, Button BM, Denehy L, Roberts SJ et al. Proximal and distal gastro-oesophageal reflux in • Lee A, Button B, Denehy L. Current Australian and NZ physiotherapy practice in the management of patients with chronic bronchiectasis and COPD. NZ Journal of Physiotherapy 2008;36(2):49-58. • Lee AL, Button BM, Denehy L, Wilson JW. Gastro-oesophageal in noncystic fibrosis bronchiectasis. Pulmonary Medicine, Volume 2011 (2011), Article ID 395020, 6 pages, doi:10.1155/2011/395020. • Lee AL, Denehy L, Wilson JW, Roberts S, Stirling R, Heine RG, Button BM. Upright positive expiratory pressure therapy and exercise: effects on gastroesophageal function in COPD and bronchiectasis. Resiratory Care 2012;57(9):1460-1467. • Lee AL, Button BM, Denehy L, Roberts SJ, Bamford TL, Ellis SJ, Mu FT, Heine RG, Stirling RG, Wilson JW. Proximal and distal gastro-oesophageal reflux in chronic obstructive pulmonary disease and in bronchiectasis. Respirology 2014 19: 211-217. • Ledson MJ, Tran J, Walshaw MJ. Prevalence and mechanisms of gastro-oesophageal reflux in adult cystic fibrosis patients. J Royal Soc Med 1998;91: 7-9. • Ledson MJ, Wilson GE, Tran J, Walshaw MJ. Tracheal microaspiration in adult cystic fibrosis. J Royal Soc Med 1998;91: 10-12. • Malfroot A, Dab I. New insights on gastro-oesophageal reflux in cystic fibrosis by longitudinal follow up. Arch Dis Child 1991; 66: 1339-1345.

• Newell SJ, Booth IW, Morgan MEI, McNeish AS. Gastro-esophageal reflux in the pre-term infant. Pediatr Res 1987;22:A104. • Orenstein SR, Orenstein DM. Gastroesophageal reflux and respiratory disease in children. J Pediatr 1988; 112: 847-858. • Orenstein DM. Heads up! clear those airways! Pediatr Pulmonol 2003;35(3):160-1. • Palm K, Sawicki G, Rosen R. The impact of reflux burden on Pseudomonas positivity in children with cystic fibrosis. Paediatric Pulmoology 2012; June 47(6):582-7. • Puetz et al. Gastroesophageal-induced cough syncope. Am J of Gastroenterology 1995:90(12): 2204-6. • Scott RB, O’Loughlin EV, Gall DG. Gastroesophageal reflux in patients with cystic fibrosis. J Pediatr 1985; 106: 223-227. • Stringer DA, Sprigg A, Juodis E, Corey M, Daneman A, Levison HJ, Durie PR. The association of cystic fibrosis, gastroesophageal reflux, and reduced pulmonary function. Can Assoc Radiol J 1988; 39: 100- 102. • Vandenplas Y, Diericx A, Blecker U, Lanciers S, Deneyer M. Oesophageal pH monitoring data during chest physiotherapy. J Pediatr Gastroenterol and Nutr 1991; 13: 23-26. • Vinocur CD, Marmon L, Schidlow DV, Weintraub WH. Gastroesophageal reflux in the infant with cystic fibrosis. Am J Surg 1985; 149: 182-186. • Wynne JW, Modell JH. Respiratory aspiration of stomach contents. Ann Intern Med 1977; 87: 466-474. • Yankaskas JR, Marshall BC, Sufian B, Simon RH, Rodman D. Cystic Fibrosis Adult Care. Chest 2004; 125:1S-39S. • Zoumot Z, Wilson R. Respiratory infection in noncystic fibrosis bronchiectasis. [Review] [40 refs]. Current Opinion in Infectious Diseases 2012;23(2):165-70. (Nontuberculous myobacterial infections associated with aspergillus & GOR)

Positioning

Craig B, Becklake M et al. “Closing volume” and its relationship to gas exchange in seated and supine positions. J Appl Physiol 1971; 31 (5):717- 721. Frownfelter D and Dean E. Cardiovascular and Pulmonary Physical Therapy; evidence and practice 2006; Chapter 19: Body positioning. Fourth edition:307-324. Kaneko K, Bates DV et al. Regional distribution of ventilation and perfusion as a function of body position. J Appl Physiol 1966;21(3):767-777. Krieg S et al. Position affects distribution of ventilation in the lungs of older people: an experimental study. AJP 2007;53:179-184. Lannefors L and Wollmer P. Mucus clearance with three chest physiotherapy regimes in CF: a comparison between postural drainage, PEP and physical exercise. Eur Respir J 1992;5:748-753. Button B, Phelan P et al. Postural drainage in CF: is there a link with gastro- oesophageal reflux? J Pediatr Child Health 1998;34:330-334. Elkins MR, Alison JA, Bye PT. Effect of body position on maximal expiratory pressure and flow in adults with CF. Pediatr Pulmonol 2005;40(5):385-91. Cecins NM, Jenkins SC, Pengelley J, Ryan G. The Active Cycle of Breathing Techniques – to Tip or Not to Tip? Respiratory Medicine 93; 660-665, 1999.

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Urinary incontinence and pelvic floor muscle function in healthy individuals and in lung disease (women and men) • Burge AT, Holland AE, Sherburn M, Wilson J, Cox NS, Rasekaba TM, McAleer R, Morton J, Button BM. Prevalence and impact of urinary incontinence in men with cystic fibrosis Physiotherapy 2015; 101:166-70 • Burge AT, Lee AL, Kein C, Button BM, Sherburn MS,Miller B, Holland AE, Prevalence and impact of urinary incontinence in men with chronic obstructive pulmonary disease: a questionnaire survey, Physiotherapy (2016), http://dx.doi.org/10.1016/j.physio.2015.11.004 • Button B, Holland A. Physiotherapy for Cystic Fibrosis in Australia: a Consensus Statement. http://www.thoracic.org.au/physiotherapyforcf.pdf. Accessed 16 April,2008. • Button BM, Sherburn M, Chase J, McLachlan Z, Wilson J, Kotsimbos T. Incontinence (urinary and bowel) in women with cystic fibrosis compared to COPD and controls: prevalence, severity and bother. Pediatric Pulmonology 2004 Suppl 27,A359. • Button BM, Sherburn M, Chase J, Stillman B, Wilson J. Pelvic Floor Muscle Function in Women with Chronic Lung Disease (Cystic Fibrosis and COPD) versus controls: Relationship to Urinary Incontinence. Pediatric Pulmonology 2005; Suppl 28, A368. • Button BM, Sherburn M, Chase J, Stillman B, Wilson J. Effect of a Three Months Physiotherapeutic Intervention on Incontinence in Women with Chronic Cough Related to Cystic Fibrosis and COPD. Pediatric Pulmonology 2005; Suppl 28, A369. • Button BM, Burge A, SherburnM et al. Prevalence and impact of urinary incontinence in adult men with CF. Pediatric Pulmonology 2011;Suppl.34:356. • Chiarelli P, Brown W, McElduff P. (1999) Leaking Urine: Prevalence and Associated Factors in Australian Women. Neururology and Urodynamics 18:567-577. • Cornaccia M, Zenorini A, Braggion C, Probelli LM, Cappelletti LM, Mastella G. (1999); Suppl(1), The Netherlands J Med; 54: S53; 117A. • Cornacchia M, Zenorini A, Perobelli S, Zanolla L, Mastella G, Braggion C. Prevalence of urinary incontinence in women with cystic fibrosis. BJU Int.2001 Jul;88(1):44-8.

• Davis A, Unsworth RJ, Webb AK, Dodd ME, (2000) Urinary incontinence: a marginalised and untreated problem in females with cystic fibrosis, 13th International Cystic Fibrosis Conference, Sweden. A218 • Gumery L, Hodgson G. Humphries N, Sheldon J, Stableforth D. Mackenzie W, Honeybourne D, Hawkins G. The prevalence of urinary incontinence in the adult male population of a regional cystic fibrosis centre. J of Cyst Fibros 2002;Vol.1 Suppl.1:351A. • McVean RJ, Orr A, Webb AK, Bradbury A, Kay L, Phillips E, Dodd ME. Treatment of urinary incontinence in cystic fibrosis. J Cyst Fibros 2003;Dec 2(4):171-6 • Miller JH, Ashton-Miller JA, deLancey JOL. A pelvic muscle pre-contraction can reduce cough- related urine loss in selected women with mild stress urinary incontinence. J Am Geriatr Soc 1998;46:870-874. • Moran F, Bradley JM, Boyle L, Elborn JS (2003) Incontinence in adult females with Cystic Fibrosis: a Northern Ireland survey. IJCP vol 57: no 3 182 • Nixon GM, Glazner JA, Martin JM, Sawyer SM. (2002) Urinary incontinence in adolescent females with Cystic Fibrosis. Pediatrics. 110( 2 Pt1): e22 • Orr A, MvVean R, Webb AK, Dodd ME (2001) Questionnaire survey of urinary incontinence in women with Cystic Fibrosis. BMJ Vol 322: 1521. • Prasad SA, Balfour-Lynn IM, Carr SB, Madge SL. A comparison of the prevalence of urinary incontinence in girls with cystic fibrosis, asthma and healthy controls. Pediatr Pulmonol 2006; Nov 41(11):1065-8. • Sapsford R, Richardson CA, Stanton WR. Sitting posture affects pelvic floor muscle activity in parous women: An observational study. AJP 2006;52(3):219-222. • Thomas TM, Plymat KR, Blannin J, Meade TW. (1980) Prevalence of urinary incontinence. BMJ 281: 1243-1245. • White D, Stiller K, Roney F. (2000) The prevalence and severity of symptoms of incontinence in adult cystic fibrosis patients. Physiotherapy Theory and Practice 16:35-42.

Modern Airway Clearance Physiotherapy • Blue Booklet. Physiotherapy for people with cystic fibrosis from infant to adult. European Cystic Fibrosis Society Website. International Physiotherapy Group 2009. • Blue Booklet. Physiotherapy for people with cystic fibrosis from infant to adult. European Cystic Fibrosis Society Website. International Physiotherapy Group 2018. • Button BM & Button B. Structure and Function of the Mucus Clearance System of the Lung. B.M. Button and B. Button. In Cystic Fibrosis: A Trilogy of Biochemistry, Physiology, and Therapy. Cold Spring Harb Perspect Med. 2013.3(8);pp. 227-242. • Button BM, Wilson C, Dentice R, Cox N, Middleton A, Tannenbaum E, Bishop J, Cobb R, Burton K, Wood M, Morgan F, Black R, Bowen S, Day R, Depiazzi J, Doiron K, Coumit M, Dwyer T, Elliot A, Fuller L, Hall K, Hutchins M, Kerr M, Lee A, Mans C, O’Connor L, Steward R, Potter A, Rasekaba T, Scoones R, Tarrant B, Ward N, West S, White D, Wilson L, Wood J, Holland AE. Physiotherapy for Cystic Fibrosis in Australia and New Zealand: A Clinical Practice Guideline. Respirology (2016) doi: 10.1111/resp.12764 • Lee AL, Button BM, Tannenbaum EL. Airway-clearance techniques in children and adolsecents with chronic suppurative lung disease and bronchiectasis. Frontiers in Pediatrics Mini Review. 24 January, 2017 doi:10.3389/ped.2017.000002.

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Active Cycle of Breathing Technique ACBT - 2019

Dr Brenda M. Button Adjunct Clinical Associate Professor Dept. of Respiratory Medicine The Alfred Hospital Monash University Melbourne, Victoria, Australia [email protected]

ACBT

• No equipment needed • No cost • Independent of an assistant • Upright or horizontal positions • Elements - start around 18 months of age • Easy to teach • Easy to learn • Useful for acquiring sputum samples in clinic

Active Cycle of Breathing

• First developed in New Zealand by the Mays (physiotherapist and physician) in the 1960’s

• Original name was FET (forced expiration technique)

• Name changed to ‘The Active Cycle of Breathing’ in the 1990’s to reflect all components in the technique

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Active Cycle of Breathing Techniques (ACBT)

BC BC

FET

HUFF TEE

BC=Breathing control TEE=Thoracic expansion exercises BC FET=Forced expiration technique P Agent ECFC 2012

Active cycle of breathing – ACBT Cycles: - Breathing Control - BC

- Thoracic expansion exercises - TEE

- Huffing/FET

- Coughing as necessary

- Flexible cycle

Jennifer Pryor: IPG/CF Booklet 2009

Breathing Control • Relaxed upper chest and shoulders – resting breathing • Encourage use of lower chest / diaphragmatic pattern of breathing • Around tidal volume Webber & Pryor 1993 - individual resting breathing pattern & rate • Aim is to decrease work of breathing and minimize bronchoconstriction • Time spent on BC depends on patient - shortness of breath • Resting period between more active parts of the cycle – thoracic expansion exercises & FET/huffing

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Thoracic Expansion Exercises

• Deep breaths emphasizing inspiration • Active inspiration usually combined with a 2-3 second end inspiratory hold via an open glottis – breath hold optional • Expiration is passive, relaxed and unforced - elastic recoil “letting the elastic go” • Generally 3-5 breaths • Upper, middle or lower thoracic expansion may be encouraged Tucker et al 1999

Forced expiratory technique (huff + BC) • Used with all airway clearance techniques • Combination of 2-3 forced expirations (huffs) and periods of breathing control • Huffs from low lung volumes mobilize secretions in small peripheral airways • Huffs from mid lung volumes - mid airways (a/w) • Huffs from high lung volumes – large upper a/w • Produces supra-maximal air flow and high linear velocities • ‘Forced expiratory maneuvers are probably the most effective part of chest physiotherapy’ Van Der Schans 1997

Huffing - forced expirations

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Huffing between cycles to remove sputum

Open mouth

Open glottis (throat)

Physiological Principles behind ACBT

• Deep breaths (TEE): interdependence

• Inspiratory holds - collateral ventilation

• FET (huffs) - Equal Pressure Point Theory - EPP

TEE - Interdependence

P Agent ECFC 2012

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Collateral Ventilation

• Channels of Martin

• Canals of Lambert

• Pores of Kohn

P Agent ECFC 2012

Collateral Ventilation

• Time constants (inspiratory hold) produce even filling, compensates for asynchronous ventilation

• Mobilisation of secretions facilitated by air passing through these channels and behind secretions Menkes & Traystman 1977

• Increase in lung volume reduces resistance to airflow via the collateral channels

Equal Pressure Point

• The point at which intra-luminal & extra-luminal pressure are equal

• Narrowing of the airway at EPP – increased velocity ‘choke point’

• Beyond the EPP (downstream towards mouth) the airway is compressed which limits flow (extra-luminal pressure > intra-luminal pressure)

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Equal Pressure Point Forced expiration technique - huff

Equal Pressure 5 Point 10 15

+10 +10 20

Pressure decreases as air moves towards the mouth

Narrowing of airways at EPP  velocity (choke point)

Equal Pressure Point Theory

• Movement of the EPP towards the mouth with downstream compression of the airways creates shear forces to mobilise secretions

• Position of EPP determined by: amount of expiratory force, elastic recoil of lung, and lung volume

5 20cmH2O Equal Pressure Point (EPP) ~ 20 10 Elastic 15 Dynamic recoil 20 compression/collapse downstream

5cmH2O + airway patent 20cmH2O

= 25cmH2O

Alveolar pressure

(Pryor 1991) “squeeze” P Agent ECFC 2012

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Practical – Breathing Control • Resting tidal breathing • Patient observes breathing at his/her own rate • Upright sitting or horizontal lying (supine, L & R sides) • Start with 4 - 6 breaths • Or as long as required to regain equilibrium • Use to decrease dyspnea & bronchospasm • Avoid paroxysms of coughing • Integral part of cycle

Practical - TEE • Supported sitting (feet on floor, hips & knees at 90 degrees) or • Recumbent positions depending on areas of sputum retention +/or atelectasis

• Hands over regions (optional) Tucker et al 1999 • Slow deep breaths towards inspiratory reserve volume • Relaxed, passive expiration – using elastic recoil • 3-5 breaths – breathing control

Practical – Inspiratory Pause

• Glottis open during pause

• 2-3 seconds – shorter in breathless patient

• Avoid in presence of pneumothorax

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Practical – effective huffing • Open glottis

• Subtle closure difficult to hear

• Mouthpiece / tissues

• Fogging up mirror

• Relaxed jaw and throat

• From low, mid and high volumes

Practical - coughing

• Inspiration with closure of glottis

• Efficient cough – preserve elasticity of lung tissue Chevaillier IPG ACT Course Instruction

• Avoid cough until secretions in upper airway

• Avoid paroxysms of coughing prematurely

• Counter productive resulting in dynamic collapse

Common Misunderstandings

• Lack of breathing control

• Active expiration (forced)

• Lack of inspiratory hold – open glottis

• Not using FET at different lung volumes

• Lack of all component parts

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ACBT for children

• Start elements around 18-24 months • Deep breathing exercises: - Blowing games - Blowing toys - Ping pong ball races - Tissue butterflies - Blowing bubble • Huffing: fogging up the mirror

ACBT - evidence

• Effective in clearance of excess bronchial secretion Pryor et al BMJ 1979 • Improves lung function Webber & Pryor 1986 • No  hypoxaemia Pryor et al Thorax 1990 • No  airflow obstruction Pryor et al Respir Med 1994 • Not further improved by addition of adjuncts ® – PEP Hofmeyr et al Thorax 1986; Flutter Pryor et al Respir Med 1994; Pike et al Netherlands J Med 1999 or HFCWO Osman et al Thorax 2010 • Equivalent to AD, PEP, oscillating PEP over one year Pryor et al J of CF 2010 P Agent ECFC 2012

ACBT – useful technique • Simple & effective - good starting technique • Gentle, flexible, portable, free (costs nothing) • Start teaching from 2 years old – blowing games, ‘fogging up mirror’ • Can be used in conjunction with nebulised mucolytics • Should not be used with PEP – different physiological principles • ACBT may be the most appropriate choice for patients with smaller amounts of sputum Holland & Button 2006

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References

Cecins NM, Jenkins SC, Pengelley J, Ryan G. The Active Cycle of Breathing Techniques – to Tip or Not to Tip? Respiratory Medicine 93; 660-665, 1999 Frownfelter & Dean 2006. Chapter 22:364. Hofmeyr JL, Webber BA, Hodson ME. Evaluation of positive expiratory pressure as an adjunct to chest physiotherapy in the treatment of cystic fibrosis. Thorax 1986 41: 951-4 Kim CS, Iglesias AJ, Sackner MA. Mucus clearance by two-phase gas-liquid flow mechanism: asymmetric periodic flow model. J Appl Physiol. 1987; 62: 959-71 Lapin CD : “Airway physiology, Autogenic Drainage and Active Cycle of Breathing.” Respir Care 2002 47(7); 778-785 Miller S, Hall DO, Clayton CB : “ Chest physiotherapy in Cystic Fibrosis : A comparative study of Autogenic Drainage and the Active Cycle of Breathing Techniques with Postural Drainage.” Thorax 50; 165-169, 1995 Osman LP, Roughton M, Hodson ME, Pryor JA. Short-term comparative study of high frequency chest wall oscillation and European airway clearance techniques in patients with cystic fibrosis. Thorax 2010 65:196-200 Pike SE, Machin AC, Dix KJ, Pryor JA, Hodson ME. Comparison of Flutter VRP1 and forced expirations with active cycle of breathing techniques in subjects with cystic fibrosis. Netherlands J of Med. 1999 ; 54: S55-6 Physiotherapy for people with Cystic Fibrosis throughout life. International Physiotherapy Group for Cystic Fibrosis. Online publication: Cystic Fibrosis Worldwide Website – Chapter 2; 4th edition 2009

References Pryor JA, Webber BA, Hodson M et al. Evaluation of the forced expiration technique as an adjunct to postural drainage in the treatment of cystic fibrosis. Br med J. 1979; 2: 417-8 Pryor JA, Webber BA, Hodson ME. Effect of chest physiotherapy on oxygen saturation in patients with cystic fibrosis. Thorax 1990; 45: 77 Pryor JA, Webber BA, Hodson ME, Warner JO. The Flutter VRP1 as an adjunct to chest physiotherapy in cystic fibrosis. Respir Med 1994; 88:677-81 Pryor JA, Tannenbaum E, Scott SF, Burgess J, Cramer D, Gyi K, Hodson ME. Beyond postural drainage and percussion: Airway clearance in people with cystic fibrosis. J Cystic Fibrosis 2010 9:187-192 Respiratory Physiology. The Mosby Physiology Monograph Series. Michelle M. Cloutier. Mosby Elsevier. Philadelphia. 2007. ISBN 0-323-03628-7. Tucker B, Jenkins S, Cheong D, Robinson P Effect of unilateral breathing exercises on regional lung ventilation. Nuclear Medicine Communications 20: 815–821, 1999 Van der Schans CP. 1997. Forced expiratory manoeuvres to increase transport of bronchial mucus: a mechanistic approach. Monaldi Archives of Chest Disease 52:367-370. Webber BA, Hofmeyr JL, Morgan MDL, Hodson ME. Effects of postural drainage incorporating the forced expiration technique, on pulmonary function in cystic fibrosis. Br J of Dis Chest 1986; 80: 353-9 Wilson GE, Baldwin AL, Walshaw MJ. A Comparison of Traditional Chest Physiotherapy with the Active Cycle of Breathing in Patients with Chronic Suppurative Lung Disease. European Respiratory Journal 8 (Suppl 19); 171S, 1995

10 August 2019

Autogenic Drainage

Maggie McIlwaine, PhD, MCSP Associate Clinical Professor, School of Physical Therapy, University of British Columbia Clinical Cardiorespiratory Specialist, Physiotherapist Vancouver, BC, Canada. [email protected] 1

M. McIlwaine 2013

Autogenic Drainage

Is based on adjusting one’s breathing level and flow rate. The aim is to create a homogenous and synchronous expiratory airflow with an optimal erosive effect over the largest possible area of the lungs, especially in the obstructed regions.

M. McIlwaine 2013

Autogenic Drainage

Utilizes: - Tidal breathing performed at different levels of TLC

- 3 second breath hold with each breath

- Expiratory airflow to mobilize secretions

M. McIlwaine 2013

M. McIlwaine 1 August 2019

Autogenic Drainage

Utilizes: - Tidal breathing performed at different levels of TLC

- 3 second breath hold with each breath

- Expiratory airflow to mobilize secretions

M. McIlwaine 2013

EFFECTS OF THE EXPIRATORY AIR VELOCITY .enhance the shearing forces .amplify the negative pressure on the bronchial wall (Brunolli effect) . intensify the bronchial wall vibrations . improve the shift of the loosened mucus

M. McIlwaine 2013

Basic mechanism of airway clearance techniques

* Can be compared to the erosion phenomenon -The higher the velocity, the - higher the shearing forces

M. McIlwaine 2 August 2019

Two-phase gas liquid flow mechanism

-Using invitro flow models -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 7

Expiratory airflow with Autogenic drainage

Intervention n PEFR L/m PIFR L/s PEFR/PIFR

Huff 17 302.4±121.8 2.08±1.42 2.80 14 249±160 L/min

Cough 17 4.67±1.91 1.68±0.74 3.07 14 209±164 L/min

Low level AD 14 47±17L/min

Mid Level AD 14 85±28L/min

High Level AD 14 115±31L/min M. McIlwaine 2015

Factors which affect airflow

- Airway Resistance

- Elastic Recoil Pressure

- Bronchial Stability

- Expiratory Pressure

M. McIlwaine 2013

M. McIlwaine 3 August 2019

HIGH EXPIRATORY LINEAR AIR VELOCITIES ARE RELATED TO :

The cross-sectional area and length of the airways

M. McIlwaine 2013

Dimensions of the airways

The bronchial funnel shape and function

M. McIlwaine 4 August 2019

HIGH EXPIRATORY LINEAR AIR VELOCITIES ARE RELATED TO :

The cross-sectional area and length of the airways The bronchial resistance

M. McIlwaine 2013

Airway compression and airway obstruction

HIGH EXPIRATORY LINEAR AIR VELOCITIES ARE RELATED TO :

The cross-sectional area and length of the airways The bronchial resistance The bronchial wall stability

M. McIlwaine 2013

M. McIlwaine 5 August 2019

INSPIRATION FORCED EXPIRATION

HIGH EXPIRATORY LINEAR AIR VELOCITIES ARE RELATED TO :

The cross-sectional area and length of the airways The bronchial resistance The bronchial wall stability The recoil capacity of the alveoli The alveoli inflation The viscoelasticity properties of the mucus The mobility and strength of the resp muscles

M. McIlwaine 2013

FLOW LIMITATIONS

Flow limitation occurs because airways are compliant

Flow = Volume/second

Cross-sectional area is greater in the peripheral airways than proximal

Velocity (Not flow) must increase Velocity = Distance/second

M. McIlwaine 2013

M. McIlwaine 6 August 2019

HIGH EXPIRATORY AIR VELOCITIES

 Large airways : exhale from fully inflated lungs

 Middle large airways : exhale from moderately inflated lungs

 Small airways : exhale from slightly inflated lungs

M. McIlwaine 7 August 2019

RELATIONSHIPS BETWEEN LUNG VOLUMES 22

OBSTRUCTION OF THE AIRWAYS, NARROWING 23

M. McIlwaine 8 August 2019

Clearance from larger airways

 by sighing through open glottis from low / mid lung volume level

 by huffing through open glottis from mid / high lung volume level

 by coughing from high lung volume level

Autogenic Drainage

Utilizes: - Tidal breathing performed at different levels of TLC

- 3 second breath hold with each breath

- Expiratory airflow to mobilize secretions

M. McIlwaine 2013

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 2013

M. McIlwaine 9 August 2019

AUTOGENIC DRAINAGE

BREATHING IN

 correct posture

 relaxed

 use diaphram

 inhale the right volume

 through the nose

 hold the respiratory movement ( 1 to 3 sec. )

 upper airways open

AUTOGENIC DRAINAGE

BREATHING OUT

 through open upper airways

 the right volume

 with appropriate high flow

 avoid abnormal airway compression

 feeling and hearing the mucus move

M. McIlwaine 10 August 2019

M. McIlwaine 11 August 2019

MEFV CURVE IN HEALTH AND DISEASE

Group 2

Group 3

M. McIlwaine 12 August 2019

Group 4.

AD with very young children and newborns=assisted AD (AAD) * Basic principles are those of the AD * By means of manipulations adapt the level of the functional Vt into the VC to achieve an optimal air velocity in the targeted generations of AW‘s * Can also been induced by “bouncing” on a physio ball by means of adapted rhythmic movements * Relax * Treat with the greatest caution (or no treatment) * Mind the specific breathing mechanics

M. McIlwaine 2013

M. McIlwaine 13 August 2019

AAD

M. McIlwaine 2013 40

REFERENCES . Miller S, Hall DO, Clayton CB : “ Chest physiotherapy in Cystic Fibrosis : A comparative study of Autogenic Drainage and the Active Cycle of Breathing Techniques with Postural Drainage.” Thorax 50; 165-169, 1995.

. Lapin CD : “Airway physiology, Autogenic Drainage and Active Cycle of Breathing.” Respir. Care 47(7); 778-785, 2002.

M. McIlwaine 2013

M. McIlwaine 14 August 2019

REFERENCES

. Long-term comparative trial of Autogenic drainage versus postural drainage with percussion in cystic fibrosis. M. McIlwaine, LT. Wong, M. Chilvers, AGF. Davidson. Paediatric Pulmonology. 2010;45:1064-69. . Short-term effect of Autogenic draonage on ventilation inhomogeneity in adult subjects with stable non-cystic fibrosis bronchiectasis. Poncin W, Reychler G, Leeuwerck N. Resp Care May 2017.

M. McIlwaine 2013

DIFFERENCES IN TECHNIQUES ACBT V AD

Cycles of 3 parts – Continuous breathing relaxed Br, Dp Br & with breath hold FET. Expiration should be FET causes airway gentle, increasing compression, velocity but avoiding squeezes mucus up airway compression Only 2 – 3 huffs then Can be tiring as no rest period – less breaks, but gentler fatiguing technique

M. McIlwaine 15

Aug 2019

Physiology of and research behind PEP

Maggie McIlwaine PhD Associate Clinical Professor, School of Rehabilitation Medicine, University of British Columbia Clinical Specialist Physiotherapist, Vancouver, BC, Canada. 1

M. McIlwaine2014

What is PEP

.PEP is positive expiratory pressure provided by a fixed expiratory orifice at the mouth which temporarily increases the FRC breathing level with the aim of opening obstructed regions of the lungs.

M. McIlwaine2014

When using PEP for airway clearance, it should always be combined with a manoeuvre to increase expiratory flow rates such as huffing and breathing control

M. McIlwaine 2013 3

M. McIlwaine 1 Aug 2019

TYPES OF PEP

PEP (pressures 10 – 20cms)

HIGH PRESSURE PEP

OSCILLATING PEP

M. McIlwaine2014

TYPES OF PEP

. LOW PRESSURE PEP A) Flow dependent - Astra - TheraPEP - PariPEP - Resistex B) Flow independent - Vital signs . HIGH PRESSURE PEP - Astra . OSCILLATING PEP - Flutter - Cornet - Acapella - Quaker

M. McIlwaine2014

M. McIlwaine 2 Aug 2019

TECHNIQUES V DEVICES

TECHNIQUES DEVICES 1. Positive 1. PEP mask, expiratory PariPEP, pressure TheraPEP, 2. Flutter, Acapella, 2. Oscillating PEP Cornet, Qaker 3. Hill-Rom, Smartvest, 3. HFCC InCourage System

TECHNIQUES V DEVICES

TECHNIQUES DEVICES 1. Each technique is 1. Are instruments based on specific used to assist in physiological achieving the principles of using desired ventilation and physiological expiratory airflow. effect. 2. A technique needs 2. How one uses each to be performed in device is important such a way as to achieve the desired effect.

M. McIlwaine 3 Aug 2019

What is PEP

. How does PEP work?

. Do you use ventilation? YES NO

. Do you utilise expiratory airflow? YES NO

. Is the premise of raising FRC level while breathing through PEP a theory only or has it been demonstrated in clinical studies? YES NO

M. McIlwaine2014

Ways to Use PEP

.PEP can be used to temporarily decrease FRC in obstructed patients to improve gas exchange

.PEP can be used to mobilize secretions by allowing air to move behind secretions and combined with FET.

* For airway clearance we want to temporarily increase FRC

M. McIlwaine2014

M. McIlwaine 4 Aug 2019

PEP – low pressure: obstructed hyper-secretion patients

COLLATERAL VENTILATION

During normal breathing, the resistance through the collateral ventilation channels is high and thus no air passes through. Could reinflate excised dogs lungs using collateral ventilation. Anderson 1979. 15

M. McIlwaine 5 Aug 2019

PORES OF KOHN

First discovered in 1893, confirmed by electron microscope. Each alveoli has 50 pores, usually fluid filled. Opens with large pressure gradients (Blackstacky 1992)

COLLATERAL VENTILATION

M. McIlwaine2014

VENTILATION DURING OBSTRUCTION

COLLAPSE

M. McIlwaine 2013 18

M. McIlwaine 6 Aug 2019

THEORY BEHIND PEP

• Due to positive intrabronchial pressure, air moves behind obstructed airways via collateral channels • This continues during expiration due to altered time constants.

M. McIlwaine 2013 19

THEORY BEHIND PEP 2.

3. PEP avoids airway compression during expiration due to increased intra-luminal pressure 4. Airways are splinted open to expiratory flow to mobilzation of secretions

M. McIlwaine 2013 20

A PEP CYCLE

M. McIlwaine 7 Aug 2019

Mechanism for mobilizing secretions during PEP

. Theory- Airways splinted open ,air moves behind secretions pressure builds up, secretions are mobilised up the airways or due to the pressure gradient . . Combine with a technique to increase expiratory flow such as huffing or AD. . Original PEP technique is 12 – 15 breaths combined with huffing.

M. McIlwaine2014

Mouthpiece PEP devices

. Pari PEP device (mask optional) . Therapep device + manometer . Evidence extrapolated from PEP (mask) . Nose clips (discomfort)

M. McIlwaine2014

Mouthpiece versus Mask in PEP devices

. Research - PEP mask - results extrapolated

. ? Loss of pressure via upper airways

. Nose clips - uncomfortable

. Advantage in breathless patients

. Advantage in patients requiring O2 via nasal prongs . Inexpensive

M. McIlwaine2014

M. McIlwaine 8 Aug 2019

Physiological evidence for the Efficacy of Positive expiratory Pressure as an Airway Clearance Technique in Patients with CF

• 5 pts studied effects of ventilation distribution •Compared No PEP, Low PEP and High PEP Results -Gas mixing with both Low and High PEP , but more with High P. PEP -VC and RV with high PEP > low PEP > no PEP

M. McIlwaine 2013 25 Darbee JC. Physical Therapy 2004;84:6.

Effects of physiotherapy interventions and a cough on peak exp flow rates

Intervention Subject PEFR L/s PIFR L/s PEFR/PIFR Frequency Ratio n Huff 17 5.04±2.03 2.08±1.42 2.80

Cough 17 4.67±1.91 1.68±0.74 3.07

Vibration 17 1.58±0.73 1.06±0.27 1.51 8.4±0.4

Flutter 17 1.13±0.30 1.05±0.27 1.15 11.3±1.5

Percussion 18 0.83±0.14 0.84±0.10 0.99 7.3±0.3

Acapella 18 0.59±0.08 0.98±0.27 0.64 13.5±1.7

PEP 18 0.44±0.15 0.96±0.2 0.47

POSITIVE EXPIRATORY PRESSURE THERAPY Breathing against an expiratory resistor Maintains positive pressure within airways Increases FRC, opens up obstructed regions Combined with huffing to mobilize secretions Dwyer found PEP sig ↑MCC

M. McIlwaine 9 Aug 2019

PEP TECHNIQUE

 POSTURE - Sitting upright - Arms resting on a table - use diaphragmatic breathing

M. McIlwaine2014

PEP TECHNIQUE

 INSPIRATION - Through mask - Normal to slightly larger tidal volume breath - Use diaphragm - Normal rate of inspiration

M. McIlwaine2014

PEP TECHNIQUE

 EXPIRATION - Through mouth - Expiration is against a resistor to create a back pressure

between 10 – 20 cms H2O - should be only slightly active

M. McIlwaine2014

M. McIlwaine 10 Aug 2019

PEP TECHNIQUE

 DURATION - Repeat 12-15 breaths - Remove mask - Perform 2-3 Huffs, high to mid or mid to low lung volume - Follow with a cough and expectorate any secretions

M. McIlwaine2014

PEP TECHNIQUE

 DURATION - Repeat 5 – 6 cycles depending on secretions - Monitor pressures with manometer

M. McIlwaine2014

Long term trial of conventional postural drainage and percussion versus positive expiratory pressure.

- 40 patients, randomized study 20 in PEP group , 20 CPT group, 1 year study

- Outcome measures FEV1

PEP group Change in FEV1 + 5.98% yr.

CPT group change in FEV1 – 2.28% -Conclusion PEP superior to CPT

McIlwaine PM J. Peds 1997. 131; 33

M. McIlwaine2014

M. McIlwaine 11 Aug 2019

Long term trial of conventional postural drainage and percussion versus positive expiratory pressure.

- 66 adults, randomized study 33 in PEP group , 33 CPT group, 2 year study

- Outcome measures FEV1

PEP group Change in FEV1 – 2.11% yr.

CPT group change in FEV1 – 2.76% -Conclusion PEP as effective as CPT

Gaskin. Ped Pulmon Suppl 17 34

M. McIlwaine2014

PD to PEP in upright sitting in CF Button et al 1998

 Annual hospital bed days: - PD year mean 105 days (87-135) - PEP year: 36 days (9-83) 215 fewer days in PEP year p<0.0005

 in symptoms using PEP p<0.001

 FEV1 & FVC - p<0.001  PEP

HIGH PRESSURE PEP

M. McIlwaine 12 Aug 2019

Hi-PEP – high pressure PEP - Austria Oberwaldner 1986

-Shoulders moved close to the neck to cover and support lung apices – prevent pneumothorax - PEP breathing for 8 - 10 cycles using

increased tidal breathing – 40 to 100 cmH2O pressure - Inhales to TLC - one or more forced expirations (huffs) against resistor - The consequent mobilization of secretions usually results in coughing at low lung volume into mask - Repeated until no more sputum is produced Pneumotachygraph used in PEP prescription

M. McIlwaine 2013 37

Hi-PEP

30 – 100cmH2O Huff against resistor Cough “ ”

Hi-PEP: obstructed – hypersecretion patients

Moderately ↑ tidal breathing

M. McIlwaine 13 Aug 2019

High Pressure PEP

Similar to regular pressure PEP Prevent compression induced collapse Fixed expiratory flow rate indicates that most of flow limitation occurs in PEP mask with movement of EPP downstream Increase FVC indicates evacuation of trapped gas through previously obstructed airways

M. McIlwaine2014

UNEQUAL EMPTYING OF LUNG UNITS DURING FORCED EXPIRATION

3 2 1

EQUAL EMPTYING OF LUNG UNITS DURING HIGH PRESSURE PEP

3 2 1 + 60

M. McIlwaine 14 Aug 2019

MODIFICATIONS OF PEP THERAPY 1. Increase expiratory pressure to 20 cms H20. 2. Positioning 3. Huffing through PEP device 4. Delivery of medications through PEP device

M. McIlwaine2014

Physiological evidence for the Efficacy of Positive expiratory Pressure as an Airway Clearance Technique in Patients with CF

M. McIlwaine 2013 44 Darbee JC. Physical Therapy 2004;84:6.

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Oscillating PEP 2019

Dr Brenda M. Button Adjunct Clinical Associate Professor Dept. of Respiratory Medicine The Alfred Hospital Monash University Melbourne, Victoria, Australia [email protected]

Oscillating positive expiratory pressure (PEP) therapy - Flow operated oscillatory devices - Combine techniques of PEP with high frequency oscillations

• The Flutter  device • The Cornet device • The Acapella device • The Quake device • The AerobiKa device

Aims & rationale of OscPEP

• Prevent premature closure of bronchi • Improve mobilization of secretions - detaching sputum from airway walls via oscillation of airways • Expectoration using forced expiration technique Thompson 2002 • Flutter generates PEP: range 18-35 cmH2O • Angle determines oscillation frequency: 6-26 Hz Gumery et al 2002 • Patient’s expiratory effort determines pressure • Combination of PEP & oscillation - breaks up mucus & reduces viscosity App et al 1998

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Using the Flutter® • Sit comfortably – elbows supported • Hold Flutter® horizontally: mid range oscillations ~ 16 Hz • Seal lips around mouthpiece • Take a slightly deep breath in • Inspiratory pause / breath hold 2-3 seconds: more even distribution of air behind mucus - small airways • Breathe out normally & deeply Althaus 2009 • Keep cheeks flat & hard • Use unforced abdominal exhalation while relaxing muscles of upper chest - feel vibrations in abdomen

Mouthpiece horizontal to table = oscillations

~ 15-16 Hz – mid-range Althaus 2009

Acapella

“Choice”

• Not angle dependent • Can use in horizontal positions • Variable PEP

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- disassembly - cleaning

B.Button, December 2011

The Acapella® vs Flutter® - similarities and differences • A flow operated oscillatory PEP device • Uses a counterweighted plug & magnet instead of steel ball • Combines the resistive features of a PEP device & the vibratory features of a Flutter® device • Green - expiratory flows of more than 15L / minute • Blue - less than15 L / minute • Acapella Choice® - can be disassembled for cleaning - more durable plastic - numbers to indicate amount of PEP to provide adjustable PEP setting • A performance comparison - American Assoc. for Resp. Care 46th International Resp. Congress 2000 • Both devices gave similar amplitude and frequencies

Scientific evidence - oscillating PEP therapy

• Improved cough clearability index in vitro Flutter & rhDNase Dasgupta 1998

• Increased sputum expectoration - Flutter versus PD Konstan et al 1994

• Panbronchiolitis Burioka et al 1998

• No difference in wet or dry weight of sputum expectorated Flutter vs CPT - patients preferred Flutter Giles et al 1996

• Flutter vs PEP Mask McIlwaine et al 1997 - significant increase in hospitalization and antibiotic use in Flutter group compared to PEP- significant decrease in FVC

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Scientific evidence - oscillating PEP - Flutter®

Althaus et al 1989 - bronchial hygiene assisted by the Flutter VRP1 Girard et al 1994 - Flutter VRP1 as an adjunct to drug therapy in the management of bronchial asthma App et al 1995 - Flutter VRP1 versus AD - significant decrease in the viscosity of sputum with oscillating PEP Thompson et al 2002; Eaton et al 2007 - Non-CF bronchiectasis Flutter vs ACBT Patterson, Bradley et al 2005 Non-CF bronchiectasis Acapella vs ACBT Patterson, Bradley et al 2007 Non-CF bronchiectasis Acapella vs ‘usual ACT’

The Cornet

• Components: - adjustable mouthpiece / nosepiece - horn shaped body

- rubber hose encased within the body

- cap over distal end - cleaning challenging

HydraPEP®, AquaPEP®, BPEP therapy: A creative PEP therapy for young children • Equipment - length of tubing ~30 cm long – diameter of suction tubing - a plastic container - a column of 5 - 10 cm of water = positive expiratory pressure ± 10-20 cmH2O pressure - manometer (optional ) - attach to tubing with large PEP resistor and connector - to measure pressure

• Optional for use with children: - detergent (3-6 squirts) - food coloring (few drops).

Campbell et al 1986

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OscPEP device: flow operated AerobiKa®

AerobiKa Oscillating PEP Therapy Flow operated device Clinically supported to : • Open up the smaller airways • Improve mucus clearance • Decrease cough frequency • Reduce breathlessness • Improve exercise tolerance • Improve QOL

Evidence

Svenningsen S, Jobse BN, Hasany A, Kanhere N et al. Hyperpolarized 3He Magnetic resonance Imaging following Oscillatory Positive Expiratory Pressure Treatment in GOLD stage 11 and 111 COPD. Poster ATS Conference 2013.

N=2 subjects: smokers with COPD: 4 weeks; one improved respiratory parameters.

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AerobiKa & AeroEclipse nebulizer

Aero Eclipse nebulizer 5L flow rate – hospital

Set to breath activated (pictured) or continuous nebulization

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OscPEP with AerobiKa via trache

Comparing performance characteristics of different PEP devices • Franks, Hall etc. Respiratory Care; Jan 2019 online. • PEP devices produced small but significant variations in performance characteristics across a range of flows and settings

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Patient reported outcomes

Button 2019 WS 18 4.5

3.5

2.5

2 Series1

1.5

0.5

0 Easy use Usual ACT Effective Clear chest Effort Sputum Fatigue Time Adherence volume

Aerobika combined with mucolytics

• n=71/80 • HS 6% = 46% • HS 3% = 17% • NS 0.9% = 37%

Nebuliser used with Aerobika: - AeroEclipse 51% - AeronebGo 46% - Eflow 3%

Feedback from 70 patients - Alfred

• Age 18 – 55 • Range in lung function FEV1 20 – 90% • Positive changes +1 to +5 on VAS -5 to 0 to +5 • Resistance +1 (most positive pressure) to 5 (least) • Combined with NS / HS • Aero Eclipse nebulizer manufacture to combine • Stand alone or combined with mucolytic agents • Some who use PEP effectively do not like OscPEP – find it less effective as used to the PEP effect for sputum clearance

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Patient quotes

• ‘Works well’ - ‘Saves time combined with HS’ • ‘Pressure of Aerobika more effective than others’ • ‘Vibrates into my sinuses – helps clear them’ • ‘Inspiratory pauses increased sputum expectorated’ • ‘Use in an AD way’ - expiration to RV • ‘Easy to clean and use’ • ‘Easier to hold in hand • Can use lying down when tired’ • ‘Offers choice to Acapella’ • ‘Similar action to Flutter’ • ‘Superior BPA free plastic – less breakable’

Patient quotes • ‘Sputum thinner, able to clear old dark plugs – rate best device for ACT’ • ‘Made my physiotherapy easier faster & more effective compared to AD alone’ • ‘Use in combination with PEP- this in AM, PEP in PM’ • ‘Superior to standard OPEP (Flutter) – after 3 months increased spirometry and lung health’ • ‘I like variety in ACT – another tool to use’ • ‘Got fed up half way through trying it and went back to PEP felt Aerobika ineffective’ • ‘Best used in conjunction with PEP’ • ‘Not as effective as PEP for ACT’

Indications for use of PEP and OscPEP therapy

• Atelectasis - segmental collapse • Asthma with secretions • Bronchiectasis • Bronchial hypersecretion • Bronchitis / chronic bronchitis • Persistent productive cough • Cystic fibrosis • Hypergammaglobulinaemia • Immotile cilia syndrome • Tracheo-bronchial instability • Tracheo-oesophageal fistula

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Precautions / contra-indications: PEP & OscPEP Therapy • Frank / active haemoptysis • Epistaxis • Recent oral surgery – risk of bleeding • Undrained pneumothorax - risk of pneumothorax • Small pneumothorax treated conservatively • Large blebs / bullae with risk of pneumothorax • Oesophageal surgery / varices • Acute sinusitis • Perforated ear drum / infected ear drum with risk of perforation

Contra-indications / precautions: PEP and OscPEP therapy

• Severe cardiovascular insult or disease • Increased cranial pressure • Post lung surgery: - post lung transplant - avoid interference with healing of the anastomoses - post lobectomy • Surgical emphysema • Pulmonary embolus

References

Bottle PEP - BPEP • Andersen JB & Falk M., (1991), Chest physiotherapy in the Paediatric Age Group. Respiratory Care, 36, pp546-554 • Bellone A, Lascioli R, Rashi S, Guzzi L, Adone R. Chest physical therapy in patients with acute exacerbation of chronic bronchitis: effectiveness of three methods. Archives of Physical Medicine & rehabilitation. 2000;81(5):558-60. • Bjorkqvist M. et al, (1997), Bottle-blowing in Hospital Treated Patients with Community Acquired Pneumonia, Scandinavian Journal of Infectious Diseases, 29, pp77-82 • Campbell T. et al, (1986), The Use of a Simple Self-administered Method of Positive Expiratory Pressure (PEP) in Chest Physiotherapy after Abdominal Surgery, Physiotherapy, 72 (10), pp498-500. Oscillation PEP - Flutter & Acapella • AARC Clinical Practice Guideline: Use of Positive Airway Pressure Adjuncts to Bronchial Hygiene Therapy Respiratory Care. Respir Care. 1993; 38: 516-521. • Althaus P et al. The Bronchial Hygiene Assisted by the Flutter VRP1 (Module Regulator of a Positive Pressure Oscillation on Expiration). Eur Resp J. 1989 suppl 8; 2:693. • Althaus P. Oscillating PEP – Flutter Therapy. In: McIlwaine M, Van Ginderdeuren F, Eds. Physiotherapy for people with Cystic Fibrosis throughout life: International Physiotherapy Group/Cystic Fibrosis 2009: 20-21

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• App EM, Kieselmann R, Reinhardt D, Lindemann H, Dasgupta B, King M, Brand P. Sputum rheology changes in cystic fibrosis lung disease following two different types of physiotherapy: flutter vs autogenic drainage. Chest. 1998 Jul; 114(1):171-7. • Bradley JM, Moran FM, Elborn JS. Evidence for Physical Therapies (Airway Clearance and Physical Training) in Cystic Fibrosis: an Overview of five Cochrane Systematic Reviews. Respir Med 2006;100:191-201. • Brooks D, Newbold E, Kozar LF, Rivera M. The flutter device and expiratory pressures. J Cardiopulm Rehabil. 2002 Jan-Feb; 22(1):53-7. • Eaton T, Young P, Zeng I, Kolbe J. A randomized evaluation of the acute efficacy, acceptability and tolerability of flutter and active cycle of breathing with and without postural drainage in noncystic fibrosis bronchiectasis. Chron Respir Dis. 2007;4(1):23-30. • Figueiredo PH, Zin WA, Guimaraes FS. Flutter valve improves respiratory mechanics and sputum production in patients with bronchiectasis. Physiotherapy Research International 2012;17(1):12-20. (Flutter vs sham Flutter). • Gondor M, Nixon PA, Mutich R, Rebovich P, Orenstein DM. Comparison of Flutter device and chest physical therapy in the treatment of cystic fibrosis pulmonary exacerbation. Pediatr Pulmonol. 1999 Oct; 28(4):255- 60. • Gumery L, Dodd M, Parker A, Prasad A, Pryor J. Clinical guidelines for the physiotherapy management of cystic fibrosis. Cystic Fibrosis Trust 2002. • Guimaraes FS, Moco VJ, Menezes SL, Dias CM, salles RE, Lopes AJ. Effects of ELTGOL and Flutter VRP1 on the dynamic and static pulmonary volumes and on the secretion clearance of patients with bronchiectasis. Revista Brasileira de Fisioterapia 2012;16(2):108-13.

• Homnick DN, Anderson K, Marks JH. Comparison of the flutter device to standard chest physiotherapy in hospitalized patients with cystic fibrosis: A pilot study. Chest. 1998 Oct; 114(4):993- 7. • Konstan MW, Stern RC, Doershuk CF. Efficacy of the Flutter device for airway mucus clearance in patients with cystic fibrosis. J Pediatr 1994;124(5 Pt 1):689–693. • Lagerkvist A, Sten GM, Redfors SB, Lindblad AG, Hjalmarson O. Immediate changes in blood-gas tensions during chest physiotherapy with PEP and OscPEP in patients with CF. Resp Care 2006;51910):1154-1161. • Lee AL, Hannah C Williamson, Sarah Lorensin and Lissa M Spencer. The effects of oscillating positive expiratory pressure therapy in adults with stable non-cystic fibrosis bronchiectasis: A systematic review. Chronic Respiratory Diseases 2015;12(1):36-46. • McCarren B, Alison JA. Physiological effects of vibration in subjects with CF. ERJ 2006;27:1204-1209. • McIlwaine PM, Wong LT, Peacock D, Davidson AG. Long-term comparative trial of positive expiratory pressure versus oscillating positive expiratory pressure (flutter) physiotherapy in the treatment of cystic fibrosis. J Pediatr. 2001 Jun; 38(6):845-50. • Morrison L, Agnew J. Oscillating devices for airway clearance in people with cystic fibrosis. Cochrane Database of Systematic Reviews.2009 (1):CD006842, • Murray MP, Pentland JL, Hill AT. A randomised crossover trial of chest physiotherapy in non-cystic fibrosis bronchiectasis. Eur Respir J. 2009 Nov;34(5):1086-92. • Naraparaju S, Vaishali K, Venkatesan P, Acharya V. A comparison of the Acapella and a threshold inspiratory muscle trainer for sputum clearance in bronchiectasis – A pilot study. Physiotherapy Theory & Practice 2012;2696):353-7.

• Pryor JA, Tannenbaum E, Scott SF, Burgess J, Cramer D, Gyi K, Hodson ME. Beyond postural drainage and percussion: Airway clearance in people with cystic fibrosis. J Cystic Fibrosis 2010 9(3):187-192 • Tambascio J, de Sousa LT, Lisboa RM, Passarelli RdeC, de Souza HC, Gastaldi AC. The influence of Flutter VRP1 components on mucus transport of patients with bronchiectasis. Respiratory Medicine 2011;105(9):1316-21. • Thompson C S, Harrison S, Ashley J, Day K and Smith D L. Randomised crossover study of the Flutter device and the active cycle of breathing technique in non-cystic fibrosis bronchiectasis. Thorax 2002;57;446-448 • Valente AM, Gastaldi AC, Cravo SL, Afonso JL, Sologuren MJJ, Guimaraes AC. The effect of two techniques on the characteristics and transport of sputum in patients with bronchiectasis: a pilot study. Physiotherapy 2004;90(3):158-64. • Van Winden CM, Visser A, Hop W, Sterk PJ, Beckers S, de Jongste JC. Effects of flutter and PEP mask physiotherapy on symptoms and lung function in children with cystic fibrosis. Eur Respir J. 1998 Jul; 12(1):143-7. • Volsko TA, DiFiore J, Chatburn RL. Performance comparison of two oscillating positive expiratory pressure devices: Acapella versus Flutter. Respir Care. 2003 Feb; 48(2):124-30. • West K, Wallen M, Follett J. Acapella vs. PEP mask therapy: a randomised trial in children with cystic fibrosis during respiratory exacerbation. Physiother Theory Pract. 2010;26(3):143-9. • Xiang-yu Zhang, Qixing Wang, Shouqin Zhang, Weilin Tan, Zheng Wang, Jue Li. The use of a modified, oscillating positive expiratory pressure device reduced fever and length of hospital stay in patients after thoracic and upper abdominal surgery: a randomised trial. J Physiotherapy 2015;61:16-20.

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Aerobika

• Suggett J. 2017 (Trudell). A retrospective cohort study demonstrating the impact of an OPEP device on exacerbations in COPD patients with chronic bronchitis. ERS 2016 Eur Respir J 2016, 48: PA3780.

• Svenningsen S, Jobse BN, Hasany A, Kanhere N et al. Hyperpolarized 3He Magnetic resonance Imaging following Oscillatory Positive Expiratory Pressure Treatment in GOLD stage 11 and 111 COPD. Poster ATS Conference 2013. N=2 subjects: smokers with COPD: 4 weeks; one improved respiratory parameters. • Franks, Hall etc. Respiratory Care; Jan 2019 online. PEP devices produced small but significant variations in performance characteristics across a range of flows and settings

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Basic Airway Clearance Class: High Frequency Chest Wall Oscillation and Intrapulmonary Percussion

Catherine O’Malley, RRT Chicago, IL [email protected] October 30, 2019

PRESENTER DISCLOSURE Catherine O’Malley, RRT

There are no relationships to disclose related to this presentation.

1 8/5/2019

Agenda

Mechanical/Percussive Devices for Airway Clearance

• Focus: cystic fibrosis • History of HFCC • HFCWO and IPV – What does it do? – How does it work? – What are the applications? – Market choices

High Frequency Chest Wall Oscillation

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HFCWO: History • New York 1966: Dr. Gustav Beck developed a thoracoabdominal belt that helped several patients clear mucus • In early 1980’s Canadian scientists led by Dr. Malcolm King studied HFCWO and showed enhanced mucus clearance in dogs • 1985: Dr. Warren Warwick and Leland Hansen developed the first “vest” airway clearance system for clinical use • 1988: FDA approval • A decade of abundant studies and several prototypes • HFCWO recognized as standard of care therapy for airway clearance

Dr. Warren Warwick

…and Leland Hansen

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HFCWO: What does it do?

• Delivers high frequency oscillations to the chest wall • Compresses and releases chest wall (“mini- coughing”) • Provides reliable and consistent airway clearance • Easy to operate • Allows for independent care

HFCWO: How does it work?

• General features include an inflatable vest, hoses and air-pulse generator • Delivers short rapid air pulsations at a variety of frequencies and pressure to – Increase airflow velocity – Alter physical properties of mucus, decreasing viscosity and mobilizing • Air-pulse generator settings – Frequency (Hertz) – Pressure – Time • Waveforms: Square, Sine, and Triangle

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HFCWO: How does it work? • General features include an inflatable vest, hoses and air- pulse generator • Delivers short rapid air pulsations at a variety of frequencies and pressure to – Increase airflow velocity – Alter physical properties of mucus, decreasing viscosity and mobilizing • Air-pulse generator settings – Frequency (Hertz) – Pressure – Time • Waveforms: Square, Sine, and Triangle

Comparison of Flow Rates for Secretion Clearance Modalities

Type Flow Rate Ratio

Relaxed 120 mL/sec. 1x Breathing

CPT 480 mL/sec. 4x

Flutter 480 mL/sec. 4x

HFCWO 1943 mL/sec. 16x

Cough 3429 mL/sec. 29x

Information can be found @ : http://www.thevest.com/physicians

HFCWO settings • Frequency – Low: 5-10 hertz – Medium: 10-15 hertz – High: 15-20 • Pressure – 1-10 – How much is enough? • Time – Original standard total treatment time in CF care: 30 minutes – Pause every 5 minutes to huff and cough

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HFCWO Waveforms: Do they matter? • Square – Maintains constant pressure – Rotating valve: pulses air, then vents pressure – Highest airflows and largest volume displacement occur at same frequencies • Sine – Continuous inflation with biased airflow to fixed pressure – Pulse pressures generated by a diaphragm moving back and forth – Highest airflows and largest volume displacement occur at different frequencies • Triangle – A “different” rotating valve – Limited evidence suggests advantages – Highest airflows and largest volume displacement occur at same frequencies

Minnesota Vest Protocol (MVP)

Frequency Pressure Time (minutes)

8 10 5

9 10 5

10 10 5 18 6 5

19 6 5

20 6 5

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MVP ages 1-4 years

Frequency Pressure Time (minutes)

13 6 5

12 6 5

11 6 5 10 6 5

9 6 5

8 6 5

What helps it work well? • A proper vest fit. • Vary the frequencies • Enough pressure to be effective and tolerated • Huffing and coughing…airway clearance!

HFCWO: Applications • Age: 1 year and up • Introduction is critical • Easy to use • Provides independent, effective and consistent therapy • Requires minimal patient talent • Patient participation enhances effectiveness • Aerosol medications may be administered during HFCC therapy

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HFCWO: Market choices

• The Vest ® by Hill-Rom

• SmartVest ® by Electromed

• The InCourageTM by Respirtech

The Monarch

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The Afflo Vest

In summary…

Are you invested?

• HFCWO is one of several options for airway clearance • Popular option in the United States • HFCWO allows for independent care • HFCWO requires patient participation in order to optimize therapy

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Intrapulmonary Percussion

Intrapulmonary Percussion: Market choices • Intrapulmonary Percussive Ventilation (IPV®) by Percussionaire® www.percussionaire.com

• The MetaNeb® System by Hill-Rom www.hillrom.com

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Intrapulmonary Percussive Ventilation (IPV®)

Dr. Forrest Bird

IPV® : What does it do?

• Pneumatic driven phasitron delivers high flow mini-bursts of positive pressure breaths • Percusses the lungs from the inside • Increases expiratory flow • Mobilizes retained secretions • Delivers high output aerosol • Hydrates viscous mucus • Provides positive expiratory pressure and helps to resolve atelectasis

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IPV® : How does it work?

• Equipment includes a Pneumatic device and a breathing circuit called a Phasitron • Utilizes operating pressures of 25- 40 psi at variable rates • Percussion rates between 100-300 breaths per minute • Works on the Venturi principle • Operates on the theory of – Counterflow – Step inflation

A unique venturi: The Phasitron®

IPV® : Step inflation and Counterflow

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IPV® : Applications • Appropriate for any age • An option for patients unable to clear their secretions • Home unit available • Adjustable driving pressure • Measures delivery pressure • A reusable and disposable circuit • Utilize with a variety of interfaces – Mouthpiece – Mask – Inline with mechanical ventilation

The MetaNeb® System

Three modes of therapy: • CPEP: lung expansion • CHFO: secretion mobilization • Aerosol delivery

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The MetaNeb

The MetaNeb circuit

The MetaNeb cycle

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IPV® -2C

• Add CPAP/PEEP • Increase flow • Increase time

IPV® at home

In summary…

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Intrapulmonary percussion discussion

IPV MetaNeb • Hospital and home unit available • Hospital unit only • Adjustable driving pressure • Pressure limited to 30 cwp • Disposable and non-disposable • Disposable circuit only circuits • Venturi system • Phasitron: spring loaded venturi system

What is the consensus? • American Association of Respiratory Care (AARC) • American College of Chest Physicians (ACCP) • Association of Chartered Physiotherapists in Cystic Fibrosis (ACPCF)/Cystic Fibrosis Trust (CF Trust) • Cystic Fibrosis Foundation (CFF) • European Cystic Fibrosis Society (ECFS) …quality of evidence to ACT therapies for CF is “fair”… …little evidence to support the use of one technique over others…

• National Institute for Health ad Care Excellence (NICE) Do not offer high-frequency chest wall oscillation as an airway clearance technique for people with cystic fibrosis except in exceptional clinical circumstances… the evidence shows high- frequency chest wall oscillation is not as effective as other airway clearance techniques. (2017)

Many ACT choices • It is good to have options • Patient’s needs and preferences differ • Patient’s needs and preferences are subject to change • Seek out what works for each patient • Despite moderately convincing evidence, we know airway clearance is key in CF care… • Needed: Well-designed studies

“Lack of evidence does not mean lack of benefit.” Dean Hess

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Thank you!

17 LITERATURE REVIEW

International Physiotherapy Group for Cystic Fibrosis (IPG/CF). Physiotherapy in the treatment of cystic fibrosis. 3rd version, 2002. www.ecfs.eu (Under allied health, IPG/CF Blue Booklet).

LUNG PHYSIOLOGY AND POSITIONING

1. Anderson J B, Qvist J, Kann T. Recruiting collapsed lung through collateral channels with Positive End-Expiratory Pressure. Scand T. Resp.Dis.1979;60:260-266. Physiological basis.

2. Badr C, Elkins MR, Ellis ER. The effect of body position on maximal expiratory pressure and flow. Aus J Physiotherapy 2002;48:95-102.

3. Bhuyan U, Peters AM, Gordon J, Davies H, Helms P. Effects of posture on the distribution of pulmonary ventilation and perfusion in children and adults. Thorax 1989;44:480-484.

4. Button B, Okada S.F, Frederick C.B, Thelin W.R, Boucher R.C. Mechanosensitive ATP release maintains proper mucus hydration of airways. Science Signal, 2013 ;Jun 11(6) : 279.

5. Button BM, Button B. Structure and funcion of mucus clearance system of the lung. In Cystic Fibrosis : A triology og biochemistry, physiology and therapy. Cold Spring Harb Perspect Med 2013.3(8) :227-242.

6. Chang HK, Weber ME, King M. Mucus transport by high-frequency nonsymmetrical oscillatory airflow. J Appl Physiol 1988; 65(3): 1203-1209.

7. Crawford A.B.H, Cotton D.J, Paiva M, Engel L.A. Effect of airway closure on ventilation distribution. Journal Applied Physiology 1989;66(6):2511-2515.

8. Dasgupta B, Brown NE, King M. Effects of sputum oscillations and rhDNase in vitro: A combined approach to treat cystic fibrosis lung disease. Pediatr Pulmonol 1998;26:250-25.

9. Elkins M.R, Alison J.A, Bye P.T. Effect of body position on maximal expiratory pressure and flow in adults with cystic fibrosis. Pediatric Pulmonology 2005;40: 385– 391.

10. Fahy JV, Dickey BF. Airway Mucus Function and Dysfunction. New Eng J Med.2010;363:2233-47.

1 11. Feldman J, Traver GA, Taussig 1M. Maximal expiratory flows after postural drainage. Amer. Rev. Resp. Dis. 1979; 119: 239-245.

12. Gompelmann D, Eberhardt R, Herth F.J.F. Collateral ventilation. Respiration 2013;85(6):515-520.

13. Hasani A, Pavia D, Agnew J.E, Clarke S.W. Regional lung clearance during cough and forced expiration technique (FET): effects of flow and viscoelasticity. Thorax 1994;49:557-561.

14. Kendrick A.H. Airway clearance techniques in cystic fibrosis: physiology, devices and the future. Journal Royal Society Medicine 2007;100:( Suppl 47):3-23.

15. Kim C.S, lglesias A.L, Sackner M.A. Mucus clearance by two-phase gas-liquid asymmetric periodic flow model. Journal Applied Physiology 1987:62(3):959-971.

16. Lapin CD. Airway physiology, Autogenic Drainage and Active Cycle of Breathing.Respir. Care 2002;47(7): 778-785.

17. Macklem PT. Physiology of Cough, Ann. Otol. 1974; 83:761-767.

18. Malkem PT. Airway Obstruction and Collateral Ventilation. Physiol. Review 1971; Sl- 368-436.

19. Martin H.B. Respiratory bronchioles as the pathway for collateral ventilation. Journal Applied Physiology 1966; 21:1443–1447.

20. McCarren B, Alison J.A. Physiological effects of vibration in subjects with cystic fibrosis. European Respiratory Journal 2006;27:1204–1209.

21. McCarren B, Alison JA, Herbert RD. Vibration and its effect on the respiratory system. Australian Journal Physiotherapy 2006;52:39–43.

22. McCarren B, Alison J.A, Herbert R.D. Manual vibration increases expiratory flow rate via increased intrapleural pressure in healthy adults: an experimental study. Australian Journal Physiotherapy 2006;52:267–271.

23. McIlwaine M.P, Chilvers M, Lee Son N, Richmond M. Analysis of expiratory flow rates used in autogenic drainage. Are they sufficiently high enough to mobilize secretions? Journal of Cystic Fibrosis 2014;13:( Suppl 2): S29.

24. Mead J, Turner JM, Macklem PT. Significance of the relationship between lung recoil and maximum expiratory flow. J. Applied Physiol. 1967; 22: 95-108.

25. Mead J, Takishima T, Leith D. Stress distribution in lungs: a model of pulmonary elasticity. Journal Applied Physiology 1970;28(5):596-608.

26. Menkes H, Lindsay D, Wood L, Muir A, Macklem P.T. Interdependence of lung units in intact dog lungs. Journal Applied Physiology 1972;32(3): 681-685.

27. Menkes HA, TraystmanRJ. CollateralVentilation. Amer.Rev Res.Dis. 1977: 116; 287-309.

28. Pride NB, Peermutt S, Riley RL, Bromberger-Barnea B. Determination of maximal expiratory flow from the lungs. Applied Physiology 1967;23:646.

29. Tarran R, Button B, Boucher R.C. Regulation of normal and cystic fibrosis airway volume by phasic shear stress. Annual. Review of Physiology 2006;68:543-561.

30. Wong .W, Keers TG, Wannamaker EM, Crozier DN, Levison H, Aspin N. Effects of gravity on tracheal mucus transport rates in normal subjects and in patients with cystic fibrosis. Pediatrics 1977; 60:146-152.

AUTOGENIC DRAINAGE

1. App EM. Sputum Rheology Changes in cystic fibrosis lung disease following two different types of physiotherapy: Flutter versus Autogenic Drainage. 1998;Chest.114(l):171-177.

2. Bohlmeyer WD. Drainage van de luchtwegen. Ned. tijdschrift voor fysioter. (1968),3,121.

3. Dab IF, Alexander. The Mechanism of Autogenic Drainage studied with flow- volume curves. Mongr. Paedo, 10 (1979), pp. 50-53 (Larser Vasel 1979).

4. Dab IF, Alexander. Evaluation of the effectiveness of a particular bronchial drainage procedure called Autogenic Drainage - Cystic Fibrosis (1977) p. 185-187 (D. Baran - E. van Bogaert - European Press, Gent, Belgium).

5. Davidson AGF, McIlwaine PM, Wong LTK, Nakielna EM, Pirie GE. A comparative trial of positive expiratory pressure, autogenic drainage and conventional percussion and drainage techniques. 137 Abstract, Ped Pulmonology 1988 Suppl 2.

6. Giles DR, Wagener JS, Accurso FJ, Butlersimon N. Short-term effects of postural drainage on oxygen saturation and sput.um recovery in patients with cystic fibrosis. Chest. 1995 -108:4:952-954.

7. McIlwaine PM. Davidson AGF, Wong LTK, Pirie G. The effect of chest physiotherapy by postural drainage and autogenic drainage on oxygen saturation in cystic fibrosis. Pediatr Pulmonol 1991;( Suppl 6):291.

3 8. McIlwaine M, Wong LTK, Chilvers M, Davidson AGF. Long Term Comparative Trial of Autogenic Drainage versus postural drainage with Percussion in Cystic Fibrosis. Ped Pulmonology 2010;45:1064-69.

9. Miller S, Hall DO, Clayton CB. Chest Physiotherapy in Cystic Fibrosis: A Comparative Study of Autogenic Drainage and the Active Cycle of Breathing Techniques with Postural Drainage. Thorax 1995- 50: 165-169. Comparative trial.

10. Savci S, Ince D.I, Arikan H. A comparison of autogenic drainage and the Active Cycle of Breathing Techniques in patients with chronic obstructive pulmonary diseases. J Cardiopulmonary rehabilitation. 2000;20:37-43.

11. Schoni M, Autogenic drainage, A Modern approach to Physiotherapy in Cystic Fibrosis. J. Royal Society of Medicine. 1989; ( Suppl. 16):vol. 82.

12. Theissl B, Pfleger A, Oberwaldner B, Zach MS. Self Administered Chest Physiotherapy in Cystic Fibrosis: A Comparative Study of High-Pressure PEP and Autogenic Drainage. Lung 1992;170: 323-330.

13. Van Ginderdeuren F, Verbanck S, Van Cauwelaert K, Vanlaethem S, Schuermans D, Vincken W, Malfroot A. Chest Physiotherapy in Cystic Fibrosis:Short-Term Effects of Autogenic Drainage Preceded by Wet Inhalation of Saline versus Autogenic Drainage Preceded by IntrapulmonaryPercussive Ventilation with Saline. Respiration 2008;76:175-180.

ACTIVE CYCLE OF BREATHING

1. Cecins NM, Jenkins SC, Pengelley J, Ryan G. The active cycle of breathing techniques - to tip or not to tip Respiratory medicine 1999;93:660-665.

2. Eaton T, Young P, Zeng I et al. A randomized evaluation of the acute efficacy, acceptability and tolerability of flutter and active cycle of breathing with and without postural drainage in non cystic fibrosis bronchiectasis. Chron Respir Dis 2007;4(1):23-30.

3. Hasani A, Pavia D, Agnew JE, Clarke S.W. Regional lung clearance during cough and forced expiration technique (FET): effects of flow and viscoelasticity. Thorax. 1994;49:557-61.

4. Hofmeyer JL, Webber BA, Hodson ME. Evaluation of positive expiratory pressure as an adjunct to chest physiotherapy in the treatment of cystic fibrosis. Thorax 1986; 41: 951-954.

5. McKoy NA, Saldanha IJ, Odelola OA, Robinson KA. Active cycle of breathing technique for cystic fibrosis. Cochrane Database Syst Rev. 2012;12:CD007862.

6. Miller S, Hall DO, Clayton CB, Nelson R. Chest physiotherapy in cystic fibrosis: a comparative study of autogenic drainage and the active cycle of breathing techniques with postural drainage Thorax 1995; 50: 165-169. Note: letters to the Editor: Webber BA Thorax 1995; 50: 1123 and Nelson R, Thorax 1995; 50: 1123-4.

7. Partridge C, Pryor JA, Webber B. Characteristics of the forced expiration technique Physiotherapy 1989;75:193-4.

8. Phillips GE. Comparison of the Active cycle of breathing techniques and external frequency oscillation jacket for clearance of secretions in children with cystic fibrosis. Thorax. 1998.

9. Phillips GE, Pike SE, Jaffe A, Bush A. Comparison of active cycle of breathing and high-frequency oscillation jacket in children with cystic fibrosis. Pediatr Pulmonol 2004;37:71-5.

10. Pike SE, Machin AC, Dix KJ, Pryor JA, Hodson ME.. Comparison of flutter VRP1 and forced expirations (FE) with active cycle of breathing techniques (ACBT) in subjects with cystic fibrosis. The Netherlands Journal of medicine 1999;( Suppl 54):S55.

11. Pryor JA, Webber BA. An evaluation of the forced expiration technique as an adjunct to postural drainage. Physiotherapy 1976; 65:304-307.

12. Pryor JA, Webber BA, Hodson ME, Batten JC. Evaluation of the forced expiration technique as an adjunct to postural drainage in the treatment of cystic fibrosis. BMJ 1979;2:417-418.

13. Pryor JA, Parker RA, Webber BA. A Comparison of Mechanical and Manual Percussion as Adjuncts to Postural Drainage in the Treatment of Cystic Fibrosis in Adolescents and Adults. Physiotherapy1981;67:140-141.

14. Pryor JA, Webber BA, Hodson ME. Effect of chest physiotherapy on oxygen saturation in patients with cystic fibrosis Thorax 1990;45:77.

15. Pryor JA, Webber BA, Hodson ME, Warner JO. The Flutter VRP1 as an adjunct to chest physiotherapy in cystic fibrosis. Respir Med 1994 Oct;88(9):677-81.

16. Reisman JJ, Rivingtonlaw WB, Corey M, Marcotte J, Wannamaker E, Harcourt TD, Levison H. Role of conventional physiotherapy in cystic fibrosis. J-Pediatr. 1988; 113: 632-6.

17. Savci S, Ince DI, Arikan H. A comparison of autogenic drainage and the active cycle of breathing techniques in patients with chronic obstructive pulmonary diseases. J Cardiopulmonary Rehabilitation 2000;20:37-43.

18. Steven MH, Pryor JA, Webber BA, Hodson ME. Physiotherapy versus cough alone in the treatment of cystic fibrosis. New Zealand Journal of Physiotherapy 1992; 20: 31- 37.

19. Thompson B, Thompson HT. Forced Expiration Exercises in Asthma and their Effect on FEV1. New Zealand Journal of Physiotherapy 1968;3:19-21.

20. Thompson CS, Harrison S, Ashley J, Day K, Smith DL. Randomised crossover study of the Flutter device and the active cycle of breathing technique in non-cystic fibrosis bronchiectasis. Thorax 2002 57: 446-8.

21. Webber B, Parker RA, Hofmeyer J, Hogson M. Evaluation of self-percussion during postural drainage using the forced expiration technique. Physiotherapy Practice 1985; 1:42-45.

22. Webber BA, Hofmeyer JL, Morgan MDL, Hodson ME. Effects of postural drainage, incorporating the forced expirtion technique on pulmonary function in cystic fibrosis British journal of Diseases of the Chest 1986; 80:353-359.

23. White D, Stiller K, Wilson K. The role of thoracic expansion exercises during the active cycle of breathing techniques. Physiotherapy Theory & Practice 1997; 13: 155- 162.

24. Williams MT, Parsons DW, Frick RA et al. Acute Respiratory Infection in patients with cystic fibrosis with mild pulmonary impairment: Comparison of two physiotherapy regimens Australian Journal of Physiotherapy 2001; 47: 227-236.

25. Wilson GE, Baldwin AL, Walshaw MJ. A Comparison of Traditional Chest Physiotherapy with the Active Cycle of Breathing in Patients with Chronic Suppurative Lung Disease. European Respiratory Journal 1995;8(Suppl 19); 171.

26. Van DerSchans CP. Forced expiration manoeuvres to increase transport of bronchial mucus: a mechanistic approach. Monaldi Arch Chest Dis.1997;52:367-370.

POSITIVE EXPIRATORY PRESSURE

1. Annemarie L Lee, Hannah C Williamson, Sarah Lorensin and Lissa M Spencer. The effects of oscillating positive expiratory pressure therapy in adults with stable non- cystic fibrosis bronchiectasis: A systematic review. Chronic Respiratory Diseases 2015;12(1):36-46.

2. Christensen EF, Nedergaard T, Dahl R. Long-term treatment of chronic bronchitis with positive expiratory pressure mask and chest physiotherapy. Chest 1990; 97: 645- 50.

6 3. Christensen EF, Norregaard 0, Dahl R. Treatment of bronchial asthma with terbutaline inhaled by conespacer combined with positive expiratory pressure mask. Chest 1991;100:317-21.

4. Christensen EF, Norregaard 0. Inhaled beta 2 agonist and positive expiratory pressure in bronchial asthma. Influence on airway resistance and functional residual capacity. Chest.1993;104(4):1108-13.

5. Christensen EF. Flow-dependent properties of positive expiratory pressure devices. Br. J.Anaesthesia.1995; 74:AI57.

6. Croth S, Stafanger G, Durkson H, Anderson JB, Falk M, Kelstrup M. Positive expiratory pressure (PEP-Mask) physiotherapy improves ventilation and reduces volume of trapped gas in cystic fibrosis. Clinical Resp. Physiology 1985: 21, 339- 343.

7. Darbee J, Dadparvar S, Bensel K, Jehan A, Watkins M, Holsclaw D. Radionuclide assessment of the comparative effects of chest physical therapy and PEP mask in CF. Ped Pulmonol. 1990;Suppl.5: 257.

8. Darbee JC, Ohtake PJ, Grant BJB, Cerny FJ. Physiological evidence for the efficacy of positive expiratory pressure as an airway clearance technique in patients with cystic fibrosis. Phys Ther 2004;84:524-537.

9. Davidson AGF, McIlwaine PM, Wong LTK, Nakielna EM, Pirie GE. A comparative trial of positive expiratory pressure, autogenic drainage and conventional percussion and drainage techniques. Ped Pulmonary 1988;Suppl 2.abst137.

10. Dwyer TJ, Daviskas E, Zainuldin R, Verschuer J, Ebert S, Bye PTP, Alison JA. Effects of exercise and airway clearance (positive expiratory pressure) on mucus clearance in cystic fibrosis: a randomized crossover trial. Eur Respir J 2019;53:1801793.

11. Falk M, Kelstrup M, Anderson JB. Improving the ketchup bottle method with positive expiratory pressure (PEP). A controlled study in patients with cystic fibrosis. European J. Res. Dis. 1984- 63: 423-32.

12. Falk M, Mortensen J, Jensen C, et al. PD or PEP. Effects on tracheobronchial clearance in CF. Ped Pulmonol.1990;( Suppl 5):250.

13. Gaskin 1. Long-term trial of conventional postural drainage and percussion versus positive expiratory pressure. Ped Pulmonl. 1998;( Suppl 17):494.

14. Hengstum M, Festen J, Beurskens C, et al. Effect of positive expiratory pressure mask physiotherapy (PEP) versus forced expiration technique (FET/PD) on regional lung clearance in chronic bronchitis. European Respiratory J.1991:4: 651-54.

15. Hofmeyr JL, Webber BA, Hodson ME. Evaluation of positive expiratory pressure as an adjunct to chest physiotherapy in the treatment of cystic fibrosis. Thorax 1986; 41(12): 951-4.

16. Kaminska TM, Pearson SB. A comparison of postural drainage and positive expiratory pressure in the domiciliary management of patients with chronic Bronchial sepsis. Physiotherapy May 1988;74:5.

17. Lannefors L, Wollmer P. Mucus clearance with three chest physiotherapy regimes in cystic fibrosis. A comparison between postural drainage, positive expiratory pressure and physical exercise. Eur. Resp. J.1992;5:748-53.

18. Lee AL, Denehy L, Wilson JW, Roberts S, Sterling RG, Heine RG, Button B. Upright positive expiratory pressure therapy and exercise: Effects on gastroesophageal reflux in COPD and bronchiectasis.Respir Care 2012;57:9:1460-7.

19. Ingwersen UM, Larsen KR. Three different mask physiotherapy regimens for prevention of post-operative pulmonary complications after heart and pulmonary surgery. Intensive Care Medicine. 1993;19(5):274-81.

20. Mahlmeister MJ, Fink JB, Hoffman GL. Positive expiratory pressure mask therapy. Theoretical and practical considerations and a review of the literature. Respiratory Care 1991;36(11): 1218-29.

21. McIlwaine PM, Wong LTK, Peacock D, Davidson AGF. Long-term comparative trial of conventional postural drainage and percussion versus positive expiratory pressure physiotherapy in the treatment of cystic fibrosis. J. Pediatrics. 1997;131(4):570-574.

22. Mortensen J, Falk M, Groth S, Jensen C. The effects of postural drainage and positive expiratory pressure physiotherapy on tracheobronchial clearance in cystic fibrosis. CHEST 1991; 100, 1350-57.

23. Orlik T, Sands D, Application of positive expiratory pressure *PEP* in cystic fibrosis patient inhalations. Dev Period Med. 2015 Jan-Mar;19(1):50-9.

24. Olsén MF, Westerdahl E. Positive Expiratory Pressure in Patients with Chronic Obstructive Pulmonary Disease: A Systematic Review. Respiration 2009;77:110– 118.

25. Olsen MF, Lannefors L, Westerdahl E. Positive expiratory pressure – Common clinical applications and physiological effects. Resp Med 2015;109:297-307.

26. Paul & Downes: Postoperative Atelectasis, I.P.P.B., Incentive Spirometry and Positive End-Expiratory Pressure. Arch Surg. 198 1; II 6.

8 27. Plebania A. Usefulness of chest physiotherapy with positive expiratory pressure (PEP)- mask in HIV - infected children with recurrent pulmonary infections. Acta Paediatrica. 1997;86:1195-1197.

28. Nicolini A; Merliak F; Barlascini C. Use of positive expiratory pressure during six minute walk test: results in patients with moderate to severe chronic obstructive pulmonary disease. Multidisciplinary Respiratory Medicine 2013;8(1):19.

29. Rau JI, Torniainen M. Combining a positive expiratory pressure device with a metered- dose inhaler reservoir system using chlorofluorocarbon albuterol and hydrotluoroalkane albuterol: effect on dose and particle size distributions. Respiratory Care.2000;45:320-6.

30. Santamaria F. Positive expiratory pressure treatment: Efficacy in pulmonary diseases. J.Pediatrics.1998;133:(5):717-718.

31. Steen HJ, Redmond AO, O'Neill D, Beattie F. Evaluation of the PEP mask in cystic fibrosis. Acta Pediatr Scand 1991; 80: 51.

32. Tannenbaum E, Prasad,SA, Sacrase E, Main E. Long-term effects of positive expiratory pressure (PEP) or oscillating positive expiratory pressure (RC Cornet) on FEV1, perceived health, and preference in children with CF. Abstract European CF conference 2005.

33. Tonnesen & Stovring: Positive Expiratory Pressure (PEP) as lung physiotherapy in cystic fibrosis. A Pilot Study. Eur. J. Resp. Dis. 1984: 65, 419-420.

34. Tyrell JC, Hiller EJ, Marten J. Face mask physiotherapy in cystic fibrosis. Arch Dis. in Childhood 1986- 61(6): 598-600. Comparative trial.

35. Van Asperen PP, Jackson L, Brown J. Comparison of a positive expiratory pressure (PEP) mask with postural drainage in patients with cystic fibrosis. Aust. Paed. J. 23(S): 283-4, 1987.

36. Van Der Schans CP, Van Der Mark TW, De Vries G, et al. Effects of positive expiratory pressure breathing in patients with cystic fibrosis. Thorax; 1991: 46, 252- 26.

37. Van Der Schans CP, De Jong W. Effect of positive expiratory pressure on breathing pattern in healthy subjects. Eur. Resp. J. 1993;6(l):60-6.

38. Van Der Schans CP, De Jong W. Effects of positive expiratory pressure breathing during exercise in patients with COPD. Chest.1994;105(3): 782-9.

9 39. Van Hengstum M. Effect of positive expiratory pressure mask physiotherapy (PEP) versus forced expiration technique (FET/PD) on regional lung clearance in chronic bronchitis. Eur. Resp. J.1991; 4(6): 651-4.

40. West K, Wallen M, Follett J. Acapella vs PEP maks therapy: A randomised trial in children with cystic fibrosis during respiratory exacerbation. Physiotherapy Theory and Practice. 2010;26(3):143-9.

HIGH PRESSURE PEP

1. Oberwaldner B, Theilbl B, Rucker A, Zach MS. Chest Physiotherapy in Hospitalized Patients with Cystic Fibrosis; A Study on Lung Function Affects and Sputum Production. E. Resp. J. 1991; 4, 152-58..

2. Oberwaldner B. Forced Expirations Against a Variable Resistance: A New Chest physiotherapy Method in Cystic Fibrosis. Pediatric Pulmonary 1986; 2 (b): 358- 367.

3. Pfleger A, Theibl B, Oberwaldner B, Zach MS. Self-Administered Chest Physiotherapy in Cystic Fibrosis: A Comparative Study of High-Pressure PEP and Autogenic Drainage. Lung, 1992 170: 323-330.

4. Zach MS, Oberwaldner B. Effect of Positive Expiratory Pressure Breathing in Patients wit Cystic Fibrosis(letter). Thorax 1992; 47,66-67.

BOTTLE PEP

1. Bellone A, Lascioli R, Rashi S, Guzzi L, Adone R. Chest physical therapy in patients with acute exacerbation of chronic bronchitis: effectiveness of three methods. Archives of Physical Medicine & rehabilitation. 2000;81(5):558-60.

2. Bjorkqvist M. et al, Bottle-blowing in Hospital Treated Patients with Community Acquired Pneumonia, Scandinavian Journal of Infectious Diseases 1997;29:77-82.

3. Campbell T. et al, The Use of a Simple Self-administered Method of Positive Expiratory Pressure (PEP) in Chest Physiotherapy after Abdominal Surgery, Physiotherapy 1986;72:(10):498-500.

FLUTTER VRP I.

10 1. Althaus P et al. The bronchial hygiene assisted by the flutter VRPI (Module regulator of a positive pressure oscillation). Eur Resp J.1989;vol 2, suppl 8:693. Physiological basis.

2. App EM. Sputum Rheology Changes in Cystic Fibrosis Lung Disease Following Two Different Types of Physiotherapy: Flutter vs Autogenic Drainage. Chest. 1998;114(1):171-177.

3. Bellone A, Lascioli R, Raschi S, Guzzi L, Adone R. Chest physical therapy in patients with acute exacerbation of chronic bronchitis:effectivenss of three methods. Arch Phys Med & Rehab. 2000;81:558-60.

4. Byme N, Prasad SA, Balfour-Lynn 1, Dinwiddie R. The use of the flutter VRPI as a form of chest physiotherapy in children with cystic fibrosis. J Royal Soc Med. 1993;86:9:( Suppl 20):23.

5. Chatham K, Marshall C, Campbell IA, Prescott RJ. The flutter VRPI device for post- thoracotomy patients. Physiotherapy 1993; 79: 95-98

6. Dasgupta B, App EM, King M. Effects of the Flutter device and airflow oscillations on spinnability of cystic fibrosis sputum. Am J Respir Crit Care Med 1996;153:A69.

7. Eaton T, Young P, Zeng I, Kolbe J. A randomized evaluation of the acute efficacy, acceptability and tolerability of flutter and active cycle of breathing with and without postural drainage in noncystic fibrosis bronchiectasis. Chron Respir Dis. 2007;4(1):23-30.

8. Figueiredo PH, Zin WA, Guimaraes FS. Flutter valve improves respiratory mechanics and sputum production in patients with bronchiectasis. Physiotherapy Research International 2012;17(1):12-20. (Flutter vs sham Flutter).

9. Gondor M, Nixon PA, Mutich R, Rebovich P, Orenstein DM. Comparison of the Flutter device and chest physical therapy in the treatment of cystic fibrosis pulmonary exacerbation. Pediatr Pulmonol 1999;28:255-60.

10. Guimaraes FS, Moco VJ, Menezes SL, Dias CM, salles RE, Lopes AJ. Effects of ELTGOL and Flutter VRP1 on the dynamic and static pulmonary volumes and on the secretion clearance of patients with bronchiectasis. Revista Brasileira de Fisioterapia 2012;16(2):108-13.

11. Homnick DN. Comparison of the flutter device to standard chest physiotherapy in hospitalized patients with cystic fibrosis: a pilot study. Chest.1998;114:(4):993 -7.

12. Konstan M, Stern RC, Doershuk CF. Efficacy of the flutter device for airway mucus clearance in patients with cystic fibrosis. J. Pediatrics 1994;124(5): 689-693.

11 13. Lagerkvist A, Sten GM, Redfors SB, Lindblad AG, Hjalmarson O. Immediate changes in blood-gas tensions during chest physiotherapy with PEP and OscPEP in patients with CF. Resp Care 2006;51910):1154-1161.

14. Lindeman H. The value of physical therapy with VRPI Destin(flutter). German. Pneumologie 1992;46(12):626-630.

15. Mahesh VK, McDougal JA. Efficacy of the Flutter device for the airway mucus clearance in patients with cystic fibrosis. J. Pediatr.1996;128:165.

16. McIlwaine PM, Wong LTK, Peacock D, Davidson AGF. A long-term comparative trial of positive expiratory pressure(PEP) versus oscillating positive expiratory pressure(Flutter) in the treatment of cystic fibrosis J Pediatr 2001(June); 138:845-50.

17. Newbold ME, Tullis E, Corey M, Ross B, Brooks D. The flutter device versus the PEP mask in the treatment of adults with cystic fibrosis. Physiotherapy Canada. 2005; 57(3):199-207. 18.

19. Newhouse PA, White F, Marks JH, Homnick DN. The intrapulmonary percussive ventilator and flutter device with cystic fibrosis. Clin Peds. 1998;37:427-32.

20. Padman R, Geouque DM, Engelhardt MT. Effects of the flutter device on pulmonary function studies among pediatric cystic fibrosis patients. Delaware Medical Joumal.1999;71:13-8.

21. Pryor JA, Webber BA, Hodson ME, Warner JO. The flutter VRP1 as an adjunct to chest physiotherapy in cystic fibrosis. Resp Med 1994;88: 677-81.

22. Radtke T, Boni L, Bohnacker P, Maggi-Beba M, Fischer P, et al. Acute effects of combined exercise and oscillating positive expiratory pressure therapy on sputum properties and lung diffusion capacity in cystic fibrosis: a randomized controlled crossover trial. BMC Pulmonary Medicine 2018;18;99.

23. Schibler A, Casaulta C, Kraemer R. Rational of oscillatory breathing as chest physiotherapy performed by the flutter in patients with cystic fibrosis. Sixth Annual North American CF Conference. Washington DC. 1992; Abst.(244).

24. Tambascio J, de Sousa LT, Lisboa RM, Passarelli RdeC, de Souza HC, Gastaldi AC. The influence of Flutter VRP1 components on mucus transport of patients with bronchiectasis. Respiratory Medicine 2011;105(9):1316-21.

25. Thompson C S, Harrison S, Ashley J, Day K and Smith D L. Randomised crossover study of the Flutter device and the active cycle of breathing technique in non-cystic fibrosis bronchiectasis. Thorax 2002;57;446-448

12 26. Van Winden CM, Visser A, Hop W. Effects of Flutter and PEP mask physiotherapy on symptons and lung function in children with cystic fibrosis. Eur. Resp J.1998;12:133-7.

27. Xiang-yu Zhang, Qixing Wang, Shouqin Zhang, Weilin Tan, Zheng Wang, Jue Li. The use of a modified, oscillating positive expiratory pressure device reduced fever and length of hospital stay in patients after thoracic and upper abdominal surgery: a randomised trial. J Physiotherapy 2015;61:16-20.

ACAPELLA 1. Murray MP, Pentland JL, Hill AT. A randomised cross-over trial of chest physiotherapy in non-cystic fibrosis bronchiectasis.Eur Respir J 2009;34:1086-92.

2. Naraparaju S, Vaishali K, Venkatesan P, Acharya V. A comparison of the Acepella and a threshold inspiratory muscle trainer for sputum clearance in bronchiectasis – A pilot study. Physiotherapy Theory and Practice 2010;26:353-357.

3. Patterson JE, Bradley JM, Hewitt O, Bradbury I. Airway clearance in bronchiectasis: A randomized crossover trial of Active Cycle of Breathing Techniques versus Acapella.Respiration 2005;72:239-242.

4. Patterson, JE, Hewitt O, Kent L, Bradbury I, Elborn JS, Bradley JM. Acapella versus usual airway clearance during acute exacerbation in bronchiectasis: a randomized crossover trial. Chronic Respiratory Diseases 2007;4:67-74.

5. Valente AM, Gastaldi AC, Cravo SL, Afonso JL, Sologuren MJJ, Guimaraes AC. The effect of two techniques on the characteristics and transport of sputum in patients with bronchiectasis: a pilot study. Physiotherapy 2004;90(3):158-64.

6. Van Winden CM, Visser A, Hop W, Sterk PJ, Beckers S, de Jongste JC. Effects of flutter and PEP mask physiotherapy on symptoms and lung function in children with cystic fibrosis. Eur Respir J. 1998 Jul; 12(1):143-7.

7. Volsko TA, DeFore J,Chatburn RL. Acapella versus Flutter: Performance comparison. American Association for Respiratory Care 2000; ABSTRACT.

8. West K, Wallen M, Follett J. Acapella vs PEP mask therapy: A randomised trial in children with cystic fibrosis during respiratory exacerbation. Physiotherapy Theory and Practice. 2010;26(3):143-9.

RC CORNET 1. Blackney DA, Chipps B. Comparison of airway pressure and oscillation frequency of four airway clearance devices. Ped PulmonL 1999; Suppl (16):430.

13 2. Dasgupta B, Nakamura S, App EM, King M. Comparative evaluation of the Flutter and the Cornet in improving the cohesiveness of cystic fibrosis sputum. Ped Pulmonol. 1997;suppl(14):300.

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August 2019

25 REVIEW AIRWAY CLEARANCE

Personalising airway clearance in chronic lung disease

Maggie McIlwaine1, Judy Bradley2, J. Stuart Elborn2,3 and Fidelma Moran4

Affiliations: 1Dept of Physiotherapy, University of British Columbia, Vancouver, BC, Canada. 2Centre for Experimental Medicine, Queens University Belfast, Belfast, UK. 3National Heart and Lung Institute, Imperial College and Royal Brompton Hospital, London, UK. 4School of Health Sciences, Ulster University, Newtownabbey, UK.

Correspondence: Maggie McIlwaine, University of British Columbia, Room K3-104, BC Children’s and Women’s Hospital, 4480 Oak Street, Vancouver, BC, V6H 3V4, Canada. E-mail: [email protected]

@ERSpublications Understanding the basis of airway clearance assists in determining the most appropriate technique for the patient http://ow.ly/uQuz307iCIZ

Cite this article as: McIlwaine M, Bradley J, Elborn JS, et al. Personalising airway clearance in chronic lung disease. Eur Respir Rev 2017; 26: 160086 [https://doi.org/10.1183/16000617.0086-2016].

ABSTRACT This review describes a framework for providing a personalised approach to selecting the most appropriate airway clearance technique (ACT) for each patient. It is based on a synthesis of the physiological evidence that supports the modulation of ventilation and expiratory airflow as a means of assisting airway clearance. Possession of a strong understanding of the physiological basis for ACTs will enable clinicians to decide which ACT best aligns with the individual patient’s pathology in diseases with anatomical bronchiectasis and mucus hypersecretion. The physiological underpinning of postural drainage is that by placing a patient in various positions, gravity enhances mobilisation of secretions. Newer ACTs are based on two other physiological premises: the ability to ventilate behind obstructed regions of the lung and the capacity to achieve the minimum expiratory airflow bias necessary to mobilise secretions. After reviewing each ACT to determine if it utilises both ventilation and expiratory flow, these physiological concepts are assessed against the clinical evidence to provide a mechanism for the effectiveness of each ACT. This article provides the clinical rationale necessary to determine the most appropriate ACT for each patient, thereby improving care.

Introduction Personalised medicine has been used to describe the application of genomics, proteomics and biomarkers to precisely tailor therapy according to various characteristics of an individual patient [1]. This concept of personalised medicine can also be applied to a variety of therapies, such as airway clearance, by taking into account individual patients’ lung pathology, clinical, functional, environmental and social factors, as well as the physiological concepts underlying airway clearance techniques (ACTs) [2]. Personalised medicine results in resources being more effectively directed to the most appropriate patients, thereby ensuring that patients receive the specific techniques that optimise the likelihood of benefit in terms of lung health and time commitment. The use of ACTs can be further enhanced by the appropriate use of inhaled medications such as mucoactive agents; however, these medications are not within the scope of this review [3]. This article provides an overview of the physiological principles underlying ACTs and links these physiological principles to the evidence base of commonly used ACTs. This will help clinicians to personalise airway clearance techniques specific to patients’ underlying lung pathology as well as other

Received: Aug 18 2016 | Accepted after revision: November 29 2016 Conflict of interest: Disclosures can be found alongside this article at err.ersjournals.com Provenance: Submitted article, peer reviewed. Copyright ©ERS 2017. ERR articles are open access and distributed under the terms of the Creative Commons Attribution Non-Commercial Licence 4.0. https://doi.org/10.1183/16000617.0086-2016 Eur Respir Rev 2017; 26: 160086 AIRWAY CLEARANCE | M. MCILWAINE ET AL.

clinical, functional, environmental and social factors. While some patients with chronic lung disease are ventilated, the vast majority breathe spontaneously. As the physiological mechanisms described differ in ventilated patients, it must therefore be emphasised that this review only describes the spontaneously breathing patient [4].

Background ACTs are used to supplement the body’s mucociliary clearance system when it is impaired by disease. This system is an important lung defence mechanism consisting of airway surface liquid comprising mucus and periciliary layers (PCLs), ciliary epithelium and cough clearing mechanisms [5]. In healthy people, cilia beat at a mean frequency of 11–13 Hz [6], propelling mucus proximally up the airways at a rate of 4– 5 mm·min-1 [7, 8]. The rate of clearance is strongly influenced by the hydration state, rigidity and viscosity to elasticity ratio of the mucus [9, 10]. The mucociliary transport system is impaired in chronic suppurative lung diseases, such as cystic fibrosis (CF), primary ciliary dyskinesia (PCD) and bronchiectasis not caused by CF. This is due to the occurrence of one or more of the following conditions: dehydration of the PCL; absence of lubricant activity which prevents adhesion of mucus to airway surfaces [11]; an inherent defect within the cilia; or immunodeficiencies, including cellular defects. Any one of these may cause a failure of ciliary beat frequency and reduced mucociliary clearance. Once this mechanical defence system is breached, the lung is more susceptible to infection and inflammation that can result in further airway damage, eventually leading to bronchiectasis [12]. To be effective, ACTs should assist the body’s natural mucociliary clearance system to transport secretions proximally up the airways. Historically, to achieve mucociliary clearance, postural drainage positions were utilised primarily for drainage by relying on gravity [13]. However, there is little supporting evidence that postural drainage utilising gravity effectively mobilises secretions [14, 15]. In CF patients, gravity in a head-down position increased the mucociliary clearance rate only from 0 mm·min-1 to 3–5 mm·min-1 [8]. Based on the assumption that mucociliary clearance rates in gravity dependent positions remain the same in different lung regions, to mobilise secretions from a subsegmental airway in the lower lobe would require a patient to be placed in a head-down position for ∼1 h. Thus, positioning a patient in a head-down position for 3–5 min (as historically used in CF centres) is expected to be ineffective and may even do harm by promoting gastro-oesophageal reflux [13, 16–20]. Two studies, one in CF adults and the other in patients with chronic bronchitis using radiolabeled tracer gases demonstrated that in the side-lying position more secretions are mobilised from the dependent lung than from the nondependent lung, which suggests that the impact of body position on ventilation plays a greater role than gravity in mobilising secretions [21–23]. Since these data were published there has been limited translation of these findings into clinical practice, which is perhaps why in many countries, positioning for drainage remains a key ACT. Positioning for ventilation is discussed later. Newer ACTs rely on two overriding physiological principles. First, a mechanism to allow air to move behind obstruction and ventilate the regions distally and second, modulation of expiratory airflow in such a way as to propel secretions proximally up the airways. We describe the physiological theories and evidence underlying the use of individual ACTs in the nonventilated spontaneously breathing patient.

Principles for optimising ventilation to obstructed regions of the lung In normal healthy individuals, during inspiration, airflow takes the path of least resistance, ventilating all areas of the lung, although there may be some asynchronous ventilation secondary to regional and stratified inhomogeneity [24]. In patients with obstructed airways, secretions decrease the diameter of the airway and increase airway resistance, causing preferential ventilation of unobstructed regions and hypoventilation of obstructed regions [24]. Over time, air gradually moves behind the obstruction, but it is not expired, leading to dynamic hyperinflation of the obstructed lung unit. Several mechanisms used in ACTs optimise ventilation to obstructed lung units.

Interdependence during deep inspiration When tidal volume is increased during a deep inspiration, expanding alveoli exert a traction force on the less well expanded alveoli they surround, thereby assisting in the re-expansion of collapsed alveoli due to the elasticity of the surrounding interstitium. This is known as “interdependence”. It results in air moving into the small airways obstructed by secretions, a phenomenon that has been called Pendelluft [25] and which results from the interdependence. The theory of interdependence was proposed by MEAD et al. [26] and a physical model was created to test this hypothesis. The theory was later confirmed in clinical studies on anaesthetised dogs [27]. https://doi.org/10.1183/16000617.0086-2016 2 AIRWAY CLEARANCE | M. MCILWAINE ET AL.

Collateral ventilation Ventilation can also occur between adjacent lung segments through collateral channels [28, 29]. In healthy individuals, the importance of collateral ventilation is negligible, due to resistance to airflow being higher in the collateral channels than in the airways. However, if an airway proximal to these collaterals becomes blocked, the collateral channels allow air to move through these pathways due to the pressure differences between adjacent lung units and function to minimise collapse of lung units. Studies have shown that excised human lungs can be re-inflated using collateral channels [30, 31]. There are three types of collateral connections: channels of Lambert, pores of Kohn and pathways/channels of Martin. Channels of Lambert represent epithelium-lined tubular communications between distal bronchioles and the adjacent alveoli. These are probably the primary channels responsible for collateral ventilation [32]. Pores of Kohn are interalveolar connections. There are ∼50 pores of Kohn, varying from 3 to 13 µm in diameter in each alveolus [33, 34]. In vivo, these pores are mostly filled by fluid and act as a pathway for alveolar lining fluid, surfactant components and cells such as macrophages to move between adjacent alveoli [34]. The pathways/channels of Martin are interbronchiolar connections. Results of an experiment – with excised dog lungs, pressurised to 17 28 cmH2O indicated connections between respiratory bronchioles and terminal bronchioles from adjacent lung segments [35], suggesting that use of collateral ventilation channels forms the basis for use of positive expiratory pressure (PEP) ACTs.

3-s breath hold A 3-s breath hold is another method of ventilating obstructed lung units. When the unobstructed region of the lung has been preferentially ventilated, a pause for 3 s alters the time constants and allows air to move from the unobstructed regions, where the pressure gradient is higher, to the obstructed regions of the lung. This transient movement of gas out of some alveoli into others at the end of inspiration is known as Pendelluft flow. Multiple-breath washout tests have shown that a breath hold increases alveolar gas mixing and decreases the inhomogeneity of ventilation in normal subjects [36]. In post-operative clinical practice it has been demonstrated that a 3-s breath hold is effective in reducing atelectasis [37].

Positioning to optimise ventilation in adults and children Positioning may be used to enhance ventilation to specific lung regions where secretions are located, such as in bronchiectasis patients. The increased ventilation to those lung regions can then be used effectively to mobilise secretions [21, 22]. There are differences in chest shape and lung mechanics between adults and children which result in differences in ventilation patterns. When adults are placed in the upright position, optimum ventilation occurs in the mid and lower lobes, while perfusion is greatest in the lower lobes. Theoretically, ventilation/perfusion ratio is 1 at the level of the right middle lobe and lingula [38]. When an adult is placed in a side-lying position, the dependent lung is preferentially ventilated due to the dependent hemi-diaphragm being stretched, causing a greater length to tension ratio, with increased contractility. This creates a greater negative pleural pressure, which, clinically, results in increased ventilation [39]. Perfusion is greater to the dependent lung in both adults and children because it is gravity dependent. When very young children are placed in the side-lying position, the nondependent lung is preferentially ventilated, probably due to the differences in lung and chest wall mechanics. This occurs in children aged <12 years, causing airway closure to occur in the more dependent regions, independent of lung disease [39]. Supine is the best position to ventilate the upper lobes [38]. However, if this is not suitable, as when taking an inhaled medication, side lying may be an alternative position. Inhaled drug deposition is improved by 13% to the dependent upper lobe when healthy adults were placed in the side-lying position. Adults with mild CF lung disease improve upper lobe deposition by 4% with the same side-lying strategy [40]. Table 1 shows optimal positioning for use during airway clearance to optimise ventilation to obstructed regions of the lung, based on changes in ventilation patterns with positioning.

Use of mobilisation to increase ventilation Moving a patient into different positions affects ventilation in two different ways. First, a change in body position alters regional ventilation as noted above. Second, by increasing the mobility of a patient, oxygen demand increases, resulting in a corresponding increase in minute ventilation and lung volumes [41]. The resultant increase in ventilation allows air to move into obstructed lung units by interdependence and collateral ventilation. https://doi.org/10.1183/16000617.0086-2016 3 AIRWAY CLEARANCE | M. MCILWAINE ET AL.

TABLE 1 Optimal positioning for airway clearance techniques to enhance ventilation to obstructed regions of the lung

Optimal position Alternative, second-choice position

Secretions in upper lobes Supine Side lying Secretions in middle lobe and lingula Upright Side lying or supine Secretions in right lung Adults: right-side lying Children: left-side lying Secretions in left lung Adults: left-side lying Children: right-side lying Secretions in lower lobes Upright Side lying

Methods of utilising expiratory airflow to enhance secretion removal Increasing the velocity of the expiratory airflow in such a way as to create high shearing forces at the airway walls, and high kinetic energy that enhances the cephalad movement of secretions is a second key mechanism to mobilise airway secretions.

Cough Coughing is a normal reflex defence mechanism used to clear excessive secretions down to the 7th or 8th generation of airways [42]. During a typical cough, a deep inspiration is followed by closure of the glottis. High intrathoracic pressure (up to 300 mmHg) builds up, resulting in a high explosive, turbulent expiratory flow rate that may exceed 500 L·min-1 [43] when the glottis is opened. During this time, dynamic compression of the airways occurs, resulting in an increase in velocity and kinetic energy which produces a shear force detaching mucus from the airway walls and enhancing the cephalic movement of mucus proximally up the airways. Distal to the regions where the airways are compressed, there may be a collapse of the airways, especially when airway instability is present [43]. Cough is an effective method of clearing secretions from the larger airways in healthy individuals. However, in chronic supperative lung disease, where narrowing and “floppy” airways may close prematurely, it can have detrimental effects if used inappropriately over an extended period as the primary method of clearing secretions. When repeated coughs are used, bronchial wall instability may result from recurrent compression of the airways, thereby reducing expiratory flow and limiting the effectiveness of the cough [44]. Therefore, we recommend that ACTs be used as the primary method of mobilising secretions from the middle and small airways to the larger airways. Then one effective cough be used to clear secretions from the larger airways, thereby preserving the integrity of the larger airways.

Huff/forced expiratory manoeuvre A forced expiration manoeuvre may also be described as a “huff”. It accelerates the expiratory airflow, creating high linear velocities that shear mucus from the airway walls. Unlike a cough that is performed with a closed glottis, a huff is performed with an open glottis. The huff concept is based on the equal pressure point (EPP) theory [45]. At the EPP, dynamic compression of the airways occurs, creating an increase in the linear velocity of the expiratory airflow which propels secretions proximally. The site of the EPP is determined by the size of expiratory force, airway stability and the elastic recoil. Initiating a forced expiration at a low lung volume shifts the EPP to the periphery, targeting secretions in the small airways. Similarly, initiating a forced expiration from a high lung volume will move the EPP centrally towards the thoracic aperture. This is sometimes referred to as a “huff-cough” [38].

Two-phase gas-liquid flow mechanism Mucus clearance can be modelled as a two-phase gas-liquid flow mechanism [46]. This indicates that peak expiratory flow rate (PEFR) must exceed peak inspiratory flow rate (PIFR) by ⩾10% for mucus to move proximally. The PEFR must also exceed 30–60 L·min-1 to overcome the adhesive strength by which the mucus is attached to the interface. Mucus factors affecting mucociliary clearance are the mucus depth and the viscoelastic properties of mucus. Viscosity is a liquid property of mucus, whereas elasticity is described as the energy storage with an applied stress to a solid. The rate of mucus transport is higher with viscoelastic mucus than with nonelastic viscous mucus [47]. During normal tidal volume breathing at rest, PEFR is not >30 L·min-1 and PIFR is greater than PEFR. The result is that secretions are not mobilised. In order to use airflow to mobilise secretions it is necessary to optimise the expiratory airflow so that PEFR>PIFR by ⩾10%, and the velocity of the expiratory flow https://doi.org/10.1183/16000617.0086-2016 4 AIRWAY CLEARANCE | M. MCILWAINE ET AL.

rate is ⩾30–60 L·min-1, depending on the properties of the secretions. In a clinical study that examined the effect of a cough and a huff on regional lung clearance, mean PEFR recorded with a cough was 288 ±29 L·min-1 and 203±25 L·min-1 with a huff [48]. Both were sufficient to increase tracheobronchial clearance by 44% and 42%, respectively, confirming that an increase in PEFR will enhance lung clearance [48]. Further studies have demonstrated that, in addition to huffing and coughing, manual vibration, oscillating PEP (using the Flutter VRP1; VarioRaw, Aubonnie, Switzerland) and autogenic drainage met the criteria for using expiratory flow to mobilise secretions proximally [49, 50] (table 2).

Effects of expiratory airflow on airway surface liquid Studies have been conducted on the effect of airflow on the volume of airway surface liquid (ASL), using an oscillatory motion device and a cyclic compressive device [47, 52]. The use of these devices caused normal airway cell cultures to double their ASL height with oscillatory motion of 0.3–0.4 Hz, and CF cultures to increase their ASL height to ∼7 µm, thereby becoming capable of maintaining mucus transport for protracted intervals. It is hypothesised that oscillatory shear stress stimulates ATP, which in turn stimulates calcium-mediated chlorine secretion and inhibits sodium absorption. These important physiological findings provide some basis for the use of airway clearance techniques utilising expiratory airflow and pressure support. However, the oscillation rate of 0.3–0.4 Hz, which is defined in these experiments, is only slightly greater than the rate of breathing in an adult, and does not equate to the oscillation rate of 11–15 Hz described later as the oscillation rate necessary for effective airway clearance. Further studies are needed to confirm these in vitro experiments.

Oscillation Oscillation frequencies of 5–17 Hz improve tracheal mucus clearance rates in dogs, with frequencies of 11– 15 Hz increasing mucus clearance from 8.2 mm·min-1 to 26 mm·min-1 [53], which corresponds to the ciliary beat frequency. In addition, oscillations have an effect on the mucus rheological properties of mucus rigidity (sum of viscosity and elasticity), spinnability (thread forming capacity of mucus) and a derived cough clearance index (CCI). A higher CCI indicates that the mucus is easier to clear with a cough. In an in vitro study, oscillations at 19 Hz using an oscillatory PEP device (Flutter VRP1) resulted in only a small nonsignificant decrease in mucus rigidity and no significant change in the CCI [54]. The use of recombinant human (rh)DNase had the same effect. However, when oscillations were combined with rhDNase the result was a significant decrease in rigidity and a significant change in the CCI. A 4-week clinical study confirmed the findings from the in vitro study and demonstrated a significant decrease in sputum rigidity and spinnability following oscillation with the Flutter compared to autogenic drainage [55]. In another study of CF patients who exercised for 20 min on a treadmill, there was also a significant reduction in sputum rigidity [56]. This result may be due to trunk oscillations associated with treadmill exercise.

Vibrations Vibrations are the application of fine manual oscillatory movements (either back and forth or side to side) applied to the chest wall during expiration. In studies of healthy subjects vibrations increase PEFR by 50% over relaxed expiration [57, 58]. The frequency of vibration and its effect on expiratory airflow has been compared to several other airway clearance interventions in clinical studies: Acapella (Smiths Medical International, Hythe, UK), PEP, Flutter and percussion [49]. Vibration was applied during expiration after a slow maximal inspiration (table 2). The resultant PEFR of 94.8 L·min-1 and PEFR/PIFR ratio of 1.51 were sufficient to assist in mucus clearance and were greater than the other interventions, but lower than a

TABLE 2 Effects of airway clearance interventions on peak flow rates

Subjects n PEFR L·min-1 PIFR L·min-1 PEFR/PIFR ratio Frequency Hz

Huff 17 302.4±121.8 124.8±85.2 2.80 Cough 17 280.2±114.6 100.8±44.4 3.07 Vibration 17 94.8±43.8 63.6±16.2 1.51 8.4±0.4 Autogenic drainage 14 85.2±28.8 50.4±13.8 1.69 Flutter 17 67.8±18.0 63.0±16.2 1.15 11.3±1.5 Percussion 18 49.8±8.4 50.4±6.0 0.99 7.3±0.3 Acapella 18 35.4±4.8 58.8±16.2 0.64 13.5±1.7 PEP 18 26.4±9.0 57.6±12.0 0.47

Data are presented as n or mean±SD. Data from [49–51]. PEFR: peak expiratory flow rate; PIFR: peak inspiratory flow rate; PEP: positive expiratory pressure.

https://doi.org/10.1183/16000617.0086-2016 5 AIRWAY CLEARANCE | M. MCILWAINE ET AL.

huff or cough manoeuvre [49]. This work has added greatly to our understanding of the effects of vibration, particularly its impact on expiratory flow rates. In addition, based on studies demonstrating that oscillation frequencies of 5–17 Hz improve mucociliary clearance [52], there is a sound rationale to suggest that vibrations with a frequency of <17 Hz will improve mucociliary transport [49, 58].

Applying physiological principles to airway clearance techniques In order to determine which ACT is most suitable for the individual patient, it is important to understand how each ACT incorporates the physiological elements of ventilation and expiratory airflow, as described earlier. Both are essential for enhancing mucus clearance. Table 3 gives a synopsis of the physiological basis for each ACT followed by a more detailed outline of their physiological components. The ACTs included in this section are evidence based and have randomised controlled long-term clinical trials to support their use. There are other ACTs and ACT devices in use, and which are currently being researched, but they have not been included in this review as they lack the rigour of evidence from long-term studies.

Active cycle of breathing techniques The active cycle of breathing techniques (ACBT) ventilates behind obstructed lung units, using interdependence and collateral ventilation, during thoracic expansion exercises [59]. A 3-s breath hold is included at the end of inspiration. This increases alveolar gas mixing and decreases the inhomogeneity of ventilation [36] (table 3). The main driver of expiratory airflow is huffing, which relies on the use of EPP to enhance mucus clearance. The peak expiratory flow rate, with a huff at high lung volume, is similar to a cough (table 2), demonstrating that the increase in air flow linear velocity is sufficient to promote cephalic movement of secretions [60]. Both the breathing level at which the huff is performed and the strength of the huff are adjusted to allow the EPP to occur where the secretions are located. As huffing is a forced expiration manoeuvre, which can lead to bronchospasm, it is necessary to intersperse it with breathing control, i.e. the forced expiration technique, which is a combination of huffing and breathing control [61]. ACBT is performed in either upright, recumbent or drainage positions [60].

Autogenic drainage In autogenic drainage, ventilation to obstructed lung regions is achieved using a 3-s breath hold on inspiration during tidal volume breathing, utilising the collateral ventilation channels. The expiratory airflow is modulated so that at each level (unsticking phase, collecting phase and evacuating phase), tidal volume breathing is performed and the expiratory airflow velocity is maximised without causing dynamic compression of the airways (figure 1) [43, 62]. In a study with patients who had obstructive lung disease, when autogenic drainage was performed, the expiratory airflow varied in the range 40–70 L·min-1 depending on lung volume and level of breathing, thereby moving secretions proximally [50]. A slow inspiratory flow rate is necessary to create an expiratory flow rate bias by ⩾10%. Autogenic drainage is usually performed in an upright position; an alternative position may be used to enhance ventilation to specific lung regions.

PEP mask – This is a flow-regulating technique employing PEPs of 10 20 cmH2O [63, 64]. Functional residual capacity (FRC) is temporarily increased by breathing through a closed system using a PEP mask (figure 2) [65]. Usually PEP is performed in a sitting position and the patient is instructed to take 12–15 tidal volume breaths through the PEP mask before it is removed for huffing [66]. If the patient removes the mask prematurely, before completing 12 breaths, or uses a mouthpiece without a good seal, the positive pressure in the airways is lost and FRC returns to normal, thereby lessening the effect of the technique. The effect of an application of PEP on collateral channels was demonstrated by MARTIN [35]. The PEP technique uses a pressure similar to that used in studies on the effect of pressure on ASL [47, 52]. Therefore, it may also enhance mucociliary transport by increasing ASL. While ventilation is improved through the use of the PEP mask, the expiratory airflow necessary to mobilise secretions proximally is not achieved, as PEP only has a PEFR/PIFR of 0.47 [49]. Therefore, PEP must be combined with a manoeuvre such as huffing or autogenic drainage.

Oscillating PEP Flutter and Acapella devices generate an automatically controlled oscillating PEP, although both utilise different physiological bases. They provide similar frequency of oscillation within the range necessary to decrease the viscoelastic and spinnability properties of mucus, and thereby improve mucus clearance [53, – – 55.] Flutter oscillates with frequencies 15 29 Hz, with average PEPs of 5 19 cmH2O. Acapella oscillates – – with frequencies of 13 30 Hz, with an average pressure of 6 21 cmH2O [67]. These oscillation frequencies are much higher than the 0.3–0.4 Hz [47, 52] used in the in vitro experiments in which ASL height was doubled. The effect of frequencies of 6–26 Hz on ASL are still to be determined. https://doi.org/10.1183/16000617.0086-2016 6 https://doi.org/10.1183/16000617.0086-2016

TABLE 3 Physiological basis for each airway clearance technique

Ventilation Expiratory airflow Oscillation Interdependence CV Breath hold Huffing# PEFR/PIFR >1.1 PEFR >30–60 L·min-1

Active cycle of breathing Thoracic expansion Thoracic expansion Sometimes used with Uses forced Ratio 2.8 Average 302 L·min-1 No techniques exercises utilise exercises utilise CV this technique if expirations at with huffing interdependence hypoventilating different levels Autogenic drainage No Yes, with breath Uses 3-s breath hold Only used to clear Yes; emphasis is 40–70 L·min-1 Depends No hold with each breath secretions from on slow on level of breathing and larger airways if inspiration and degree of airway needed increased velocity obstruction on expiration PEP No As PEP is Not necessary as Used at end No No No maintained within PEP is maintained of each cycle of Ratio 0.47 Average 26 L·min-1 the airways over within the airways 12–15 breaths 12–15 breaths, use over 12–15 breaths of CV is maximised Oscillating PEP with Oscillations at 3–5Hz Yes with breath hold Uses 3-s breath hold Used at end of Ratio 1.15 Average 68 L·min-1 2–32 Hz Flutter may play a role, but with each breath each cycle of 8–10 Most often frequency used in breaths uses 6–26 Flutter is >5 Hz Hz Oscillating PEP with Oscillations at 3–5Hz As a PEP is Not necessary Used at end of No Average 35.4 L·min-1 10–18 Hz Acapella may play a role, but maintained within each cycle of Ratio 0.64 Within PEFR range frequency used in the airways over 12– 12–15 breaths needed, but would Acapella is >5 Hz 15 breaths, use of depend on viscoelastic CV is maximised and viscosity properties of secretions AL. ET MCILWAINE M. | CLEARANCE AIRWAY HFCWO Oscillations at 3–5Hz No No Interspersed with Yes, expiratory Average 120 L·min-1 5–25 Hz may play a role, but HFCWO flow rate is much frequency used in higher than HFCWO is >5 Hz inspiratory flow rate

CV: collateral ventilation; PEFR: peak expiratory flow rate; PIFR: peak inspiratory flow rate; PEP: positive expiratory pressure; HFCWO: high-frequency chest wall oscillation. #:each technique incorporates huffing, as used in the forced expiration technique, with the exception of autogenic drainage. 7 AIRWAY CLEARANCE | M. MCILWAINE ET AL.

Predicted values Obstructive values

Unstick Collect Evacuate Huff

TV TV

ERV

ERV RV RV

FIGURE 1 Breathing pattern during autogenic drainage. TV: tidal volume; ERV: expiratory reserve volume; RV: residual volume.

Oscillating PEP with Flutter While exhaling through the Flutter device to expiratory reserve volume (ERV), the individual tunes the device to their ventilatory ability, thereby enabling a modulation of both pressure and airflow oscillation frequency, increasing expiratory airflow, to mobilise secretions proximally [68]. Flutter produces an expiratory flow bias of PEFR/PIFR of 1.15, which is sufficient to mobilise secretions [49]. In addition, huffing is added at the end of each breathing cycle. Unlike the PEP mask, FRC is not increased with the Flutter due to the inability to inspire through the device. To overcome ventilatory asynchronism, inspiration is followed by a 3-s breath hold. While the Flutter meets the two criteria for mobilising secretions, it raises some concerns. Sometimes, expiration is into the ERV, where closing volume has the potential to cause airway closure [69]. FRC level is not temporarily increased so that the effect of PEP on opening collateral channels is negated. However, the 3-s breath has been shown to increase alveolar gas mixing, alter time constants and allow air to move distal to any obstruction. Another limitation of the Flutter is that due to its pipe-like design, it can only be used in the upright position.

Oscillating PEP with Acapella Because inspiratory and expiratory manoeuvres are performed through the Acapella in a closed system for 12–15 breaths, its physiological basis is similar to the PEP technique, allowing air to move behind secretions

Cough Slightly active TV breathing FET at different towards an expiratory lung volumes resistor TLC

Opening volume Closing volume FRC

Healthy = predicted Obstructed, volumes hyperinﬂated

FIGURE 2 Schematic representation of breathing levels during positive expiratory pressure in an obstructed patient. TV: tidal volume; FET: forced expiration technique; TLC: total lung capacity; FRC: functional residual capacity; RV: residual volume. Courtesy L. Lannefors (Sahlgrenska University Hospital, Gothenburg, Sweden). https://doi.org/10.1183/16000617.0086-2016 8 AIRWAY CLEARANCE | M. MCILWAINE ET AL.

through collateral ventilation channels as a result of an increased FRC level. The addition of oscillation should enhance the technique. Similar to PEP, the expiratory flow bias is insufficient with a PEFR/PIFR ratio of 0.64 [49], therefore the Acapella needs to be combined with huffing to assist in mucociliary clearance from the larger airways. Acapella is position independent, so it can be used in any position to optimise ventilation.

High-frequency chest wall oscillation During high-frequency chest wall oscillation (HFCWO) (also described as high-frequency chest compression), oscillations are created over the chest wall at frequencies of 5–25 Hz. On expiration the oscillations enhance mucociliary transport in three essential ways, similar to the oscillations produced with oscillatory PEP devices: 1) by altering the rheological properties of mucus [54]; 2) by creating an expiratory flow bias that shears mucus from the airway walls and encourages its movement proximally [53]; and 3) by enhancing ciliary beat frequency [70]. The oscillatory expiration flow generated by compression of the chest wall (creating a PEFR <120 L·min-1) is sufficient to overcome mucus adhesion from the airway wall and propel it up the airway. However, the HFCWO device provides no means of ventilating behind obstructed airways. Unlike the other oscillatory devices, HFCWO does not provide any PEP, and the end-expiratory volume has been reported to decrease by 10–50% during compression [71]. While this may improve expiratory flows through the smaller airways, it may worsen expiratory flows if the airways are smaller and airway resistance is increased, leading to early airway closure [72]. This may lead to a worsening of lung disease. Several short-term randomised controlled trials in CF patients have been unable to demonstrate any significant difference between HFCWO and other ACTs [73–76]. However, in two long-term studies, HFCWO was associated with an increased number of respiratory exacerbations in one [77] and by a decreased in lung function in the other [78].

Personalising airway clearance strategies While no one ACT has been found to be more effective than another, as synthesised in five Cochrane reviews [79–83] on ACTs in CF, traditionally the choice of ACT has been based on what is available locally, the training and expertise of the local physiotherapist and culture [84]. However, a one-size fits all approach based on regional preference may not address specific patient needs. An individualised strategy should take into account the patient’s disease state, preference, motivation and maturity, which, together with the physiological knowledge base of each ACT, applies the most effective airway clearance intervention for that individual. Some examples of clinical considerations based on the unique physiological principles of each ACT are as follows.

1) A deep inspiration with a 3-s breath hold is a particularly effective means of increasing ventilation in patients with a restrictive component to their lung disease [37], but using a 3-s breath hold in a patient with a severe lung disease who is tachypnoeic may lead to hypoxia. 2) A forced expiration, as used in ACBT and with the various PEP devices, needs to be adapted to the individual’s underlying lung pathology. In a patient with collapsible airways, a huff may compress the airways in such a way as to limit expiratory airflow rather than to increase the velocity of airflow [43]. Alternatively, if bronchospasm is present, airflow obstruction is greater therefore the force of the huff needs to be reduced. 3) In autogenic drainage the expiratory airflow is gently accelerated, avoiding compression of the airways. This technique is therefore more favourably suited to patients with bronchospasm, or patients with haemoptysis, where a gentler technique is required. In a clinical study, patients with bronchospasm responded best to autogenic drainage [85]. As autogenic drainage requires a self-awareness of one’sown respiratory mechanics and concentration to perform, it is generally used in teenagers or adults, unless a caregiver is skilled in its administration. 4) PEP increases FRC during tidal volume breathing, evening out intrapulmonary distribution of ventilation and opening up regions that are otherwise closed off [65]. It is therefore effective in both restricted and obstructed patients. In addition, the PEP splints the airways during expiration, thereby avoiding airway collapse, which makes it a favourable technique for patients with unstable airways. 5) Adding oscillations to expiration, either by using an oscillatory PEP device or HFCWO device, has the added advantage of increasing mucociliary clearance [53], decreasing the viscoelastic properties of mucus and potentially rehydrating mucus. When using oscillation devices, the clinician must consider what method they want to use to first ventilate behind the obstructed units. Flutter uses a 3-s breath hold; Acapella, like PEP, increases FRC, splinting airways open. HFCWO needs to be combined with either deep inspiratory manoeuvres, 3-s breath hold or PEP. 6) Exhaling into the ERV, as used during autogenic drainage, Flutter and HFCWO assist in mobilising secretions from the small airways, but have the potential to cause airway closure [62, 69, 71]. To avoid https://doi.org/10.1183/16000617.0086-2016 9 AIRWAY CLEARANCE | M. MCILWAINE ET AL.

this, during these techniques, the therapist should ensure that patients adequately incorporate methods to ventilate small airways, such as 3-s breath holds or thoracic expansion exercises. 7) A therapeutic strategy for an individual patient may involve a combination of ACTs. For example, in a patient with unstable large airways, the use of a PEP device will enhance ventilation, but during the huffing phase the airways may be unable to resist compression. By combining PEP with autogenic drainage, expiratory flow rates could be increased without causing airway compression, thereby mobilising secretions more effectively

Conclusion The approach to care of the individual patient must be personalised. In clinical practice, more than one ACT may be effective for a patient at a given time in their disease trajectory, and choice of technique may then be dependent on availability and patient preference. Other considerations include cleaning and durability of an ACT device if one is used. However, more often than not, due to the varying nature of the underlying disease pathology and phenotypic characteristics, and taking into account the clinical, functional, environmental and social factors of individual patients, ACTs need to be personalised to meet patients’ specific needs. This requires a sound understanding of the physiological basis of each technique. Examining the application of physiological principles to ACTs provides a better understanding of how to optimise airway clearance strategies to the individual patient’s underlying pathology. This allows for both more personalized, improved patient care. Physiological theories which support ACTs had previously been identified [42, 43, 86]. However, this is the first review to present the physiological evidence supporting methods that ventilate behind obstructed lung units, and modulate of expiratory airflow, and to collate this physiological evidence in an effort to assist in translation into practice.

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