CVR Physiotherapy › Technique cards › Airway clearance
PEP, flutter, Acapella and other airway-clearance devices
PEP devices were asked in seven papers: the PEP mask (W17), Acapella and Flutter (S18), two PEP devices (W18), principle with types (S21, S22), assistive devices (W21) and three uses of a PEP device (S26). Learn one principle (breathing out against resistance), three devices, and the contraindications.
- Syllabus
- Ch 4(b) Adjunct therapy: flutter and PEP therapy; practical: mechanical assistive devices (PEP, flutter, vest)
- Priority
- High yield. In 7 of 20 papers (2016–2026).
- Asked as
- 7m S21W21 3m W17S18W18S22S26
- Usual split
- 3-mark principle and two devices, or three uses; 7-mark principle, classification and types, or assistive devices
- Checked against
- BTS/ACPRC physiotherapy guideline (2009); NHS and Cystic Fibrosis Trust PEP patient guides; AARC guideline on positive airway pressure adjuncts. Full list under Sources.
- Content checked
- 19 October 2026. Next review due October 2027.
- My revision
-
1PEP: the principle
Positive expiratory pressure (PEP) therapy means breathing out against a resistance, so pressure inside the airways stays above atmospheric pressure during expiration. The usual target with a PEP mask is about 10–20 cmH₂O during the breath out.
- Splints the airways open: back-pressure stops small, floppy airways collapsing early in expiration (the same idea as pursed-lip breathing).
- Gets air behind mucus: lung volume rises a little and air moves through collateral channels into blocked units; on breathing out, that air pushes mucus towards the larger airways.
- Oscillating PEP adds vibration: the expiratory pressure flutters on and off many times a second, shaking mucus off the airway walls and making it less sticky.
The loosened mucus is then cleared with huffs and a cough.
2Types of PEP device (S21: classification and types)
| Type | Device and how it works | Points |
|---|---|---|
| Low-pressure PEP | PEP mask (or mouthpiece): one-way valve, a fixed resistor of chosen size on the expiratory side, and a manometer to check pressure | Pressure set by the physiotherapist; works in sitting or drainage positions; can be combined with a nebuliser |
| Oscillating PEP | Flutter: a pipe-shaped device with a steel ball in a cone; breathing out lifts the ball, which drops back repeatedly, causing oscillation | Must be held at the right angle, so used sitting; small and cheap |
| Oscillating PEP | Acapella: a counterweighted lever and magnet open and close the airflow; a dial adjusts resistance and frequency | Works in any position (lying, drainage positions); suits patients with low expiratory flow |
| Oscillating PEP | Other designs: RC-Cornet (curved tube with a flexible inner hose), Aerobika (oscillating valve) | Position-independent |
| Low-cost PEP | Bottle (bubble) PEP: breathing out through a tube into a bottle of water. The depth of the tube under water in cm gives the pressure in cmH₂O (10 cm deep ≈ 10 cmH₂O); bubbling adds some oscillation | Very cheap, child-friendly; keep the water clean and changed daily |
| High-pressure PEP | Forced expiration through a PEP mask at much higher pressures | Specialist use in some cystic fibrosis patients with unstable airways |
3Technique (PEP mask)
- Sit upright with elbows resting on a table (or in a drainage position).
- Hold the mask firmly over the nose and mouth (or seal the lips round the mouthpiece).
- Breathe in slightly deeper than normal; breathe out actively but not forcefully through the device, keeping the manometer at about 10–20 cmH₂O.
- Do about 8–10 such breaths.
- Remove the mask; do 2–3 huffs, then a cough to clear loosened mucus; rest with breathing control.
- Repeat the cycle until the chest feels clear, usually for about 15–20 minutes, once or twice a day (more during infections).
Flutter or Acapella: the same cycle; with the Flutter, tilt the device until the vibration is felt most in the chest. Clean devices after each use and do not share them (cross-infection, especially in cystic fibrosis).
4Uses of a PEP device (3 marks in S26)
- Airway clearance in bronchiectasis, cystic fibrosis and COPD with sputum: independent, portable, quick.
- Unstable, collapsible airways (COPD, tracheomalacia): back-pressure keeps airways open during expiration.
- Lung expansion after surgery: helps prevent and reverse collapse.
- Better aerosol delivery: a nebuliser can be connected so the drug is breathed in while PEP keeps airways open.
- Children: play-based breathing practice (bubble PEP).
5Contraindications and precautions
- Untreated pneumothorax (the main contraindication).
- Active haemoptysis.
- Raised intracranial pressure; haemodynamic instability.
- Recent facial, oral, skull or oesophageal surgery or injury; acute sinusitis; nosebleeds; middle-ear problems or a perforated eardrum.
- Patients who cannot tolerate the extra work of breathing (very breathless, exhausted).
- Large bullae: use lower pressures with care.
6Other assistive devices for airway clearance (7 marks in W21)
| Device | How it works | Used for |
|---|---|---|
| Incentive spirometer | Visual feedback (a rising piston or ball) encourages slow, deep breaths with a hold | Lung expansion after surgery, as an add-on to deep breathing and walking |
| IPPB (Bird ventilator) | Positive pressure through a mouthpiece boosts each breath the patient starts | Weak or tired patients who cannot take deep breaths; now used less. Not with an undrained pneumothorax |
| High-frequency chest wall oscillation (vest) | An inflatable vest rapidly squeezes and releases the chest wall | Cystic fibrosis, neuromuscular disease; hands-free but expensive |
| Intrapulmonary percussive ventilation | Rapid small bursts of air through a mouthpiece, with nebulised saline | Thick secretions, neuromuscular disease |
| Mechanical insufflation–exsufflation (cough assist) | A positive-pressure breath in, then a quick switch to negative pressure, often up to about ±40 cmH₂O in adults, to imitate a cough | Weak cough in neuromuscular disease and spinal cord injury |
| Manually assisted cough | The therapist pushes inwards and upwards on the abdomen or lower ribs as the patient coughs | Spinal cord injury, weak abdominal muscles (not over a fresh abdominal wound) |
| Suction | Negative pressure through a catheter | Patients who cannot cough secretions out (see the suction card) |
7Exam corner
Past questions (MUHS, 2016–2026)
- 7-mark questionsPEP devices: principle, classification and types (S21). Various assistive devices used for airway clearance (W21).
- 3-mark questionsPEP mask and its use (W17). Acapella and Flutter device and their use (S18). Two PEP devices (W18). Principle of a PEP device with two devices (S22). Any three uses of a PEP device (S26).
Answer skeleton: PEP devices, 7 marks
- [2] Principle: expiratory resistance, 10–20 cmH₂O, airway splinting, collateral ventilation, oscillation.
- [2.5] Types: PEP mask; oscillating (Flutter, Acapella, others); bottle PEP; high-pressure PEP; one line each.
- [1.5] Technique cycle: breaths, huffs, cough, duration.
- [1] Indications and contraindications.
Test yourself
3 mWrite the principle of PEP and name two devices.
Breathing out against a resistance keeps airway pressure positive (about 10–20 cmH₂O), splinting small airways open and letting air get behind mucus through collateral channels; oscillating devices also vibrate the airways. Devices: PEP mask, Flutter, Acapella (any two).
MCQA patient needs oscillating PEP while lying in a drainage position. The best device is:A. FlutterB. AcapellaC. Incentive spirometerD. Peak flow meter
B. The Acapella works in any position; the Flutter depends on gravity acting on its steel ball.
MCQThe main contraindication to PEP therapy is:A. BronchiectasisB. Undrained pneumothoraxC. Cystic fibrosisD. Post-operative collapse
B. Positive pressure could enlarge the pneumothorax.
Sources
- MUHS BPTh syllabus (2012) and MUHS IV BPTh question papers 2016–2026 (muhsonline.com, unofficial archive; Dhole Patil College of Physiotherapy past-paper page).
- Bott J, et al. Guidelines for the physiotherapy management of the adult, medical, spontaneously breathing patient (BTS/ACPRC). Thorax 2009;64 Suppl 1:i1–51.
- Cystic Fibrosis Trust. How to use a PEP mask (patient leaflet); NHS trust PEP patient guides (target pressure about 10–20 cmH₂O).
- AARC Clinical Practice Guideline: Use of positive airway pressure adjuncts to bronchial hygiene therapy. Respir Care 1993;38:516–21 (contraindications).
- Cystic Fibrosis Trust. Standards of care and good clinical practice for the physiotherapy management of cystic fibrosis, 5th edition (2026).
- Structure and classical content: Pryor & Prasad (2008); Frownfelter & Dean (2022).
Educational notes for exam preparation. Not medical advice.
Version 1. Content checked 19 October 2026. Next review October 2027.