11.2 Airway Clearance Techniques and Chest Physiotherapy
Key Takeaways
Gravity-assisted positioning is one adjunct to secretion clearance. Select the target from symptoms and available imaging, and choose a position that the patient can safely tolerate.
Intracranial hypertension and aspiration risk change the positioning plan. Follow the ordered neurocritical position and review device restrictions before choosing any alternative.
Active cycle of breathing techniques uses relaxed breathing, thoracic expansion and open-glottis huffs. A brief inspiratory hold can be used if tolerated. Adjust the volume and effort of huffs to their purpose.
PEP creates expiratory backpressure. Oscillating PEP adds fluctuations in pressure and flow. Actual settings and waveforms depend on the device, resistance and patient airflow.
Autogenic drainage progresses controlled breathing from lower to higher lung volumes. For a weak and ineffective cough, consider cough augmentation and the medical plan instead of assuming a secretion-mobilizing technique will evacuate mucus.
Airway Clearance Techniques and Chest Physiotherapy
Determine whether the patient has retained secretions, whether the cough can bring them out, and whether there is an acute medical problem. Ask about daily sputum, breathing effort, reflux, blood in sputum and current treatment. Check stability, oxygenation as indicated, position tolerance and the ability to follow instructions. A technique that mobilizes mucus still needs an effective way to evacuate it, such as huffing, coughing, assisted cough or clinically indicated suction.
1. Gravity-Assisted Positioning
Postural drainage uses gravity as one aid to moving secretions toward larger airways. A segment's orientation informs the choice, but the bronchus need not be perpendicular to the bed. Use clinical findings and available imaging to choose positions. The following examples describe familiar treatment positions. A target on imaging does not make a particular tilt mandatory.
| Target | Position used in traditional or adapted chest physiotherapy |
|---|---|
| Upper-lobe apical | Supported sitting. |
| Upper-lobe posterior | Supported forward lean or a side-lying variant selected for the target side. |
| Upper-lobe anterior | Supported supine, with the head elevated if needed and appropriate. |
| Right middle lobe | Left side-lying with a quarter turn back toward supine. |
| Left lingula | Right side-lying with a quarter turn back toward supine. |
| Lower-lobe superior | Supported prone on a level surface when tolerated. |
| Lower-lobe anterior basal | Supported supine. Some traditional protocols add head-down tilt. |
| Lower-lobe lateral basal | Side-lying with the target side uppermost, sometimes with a small rotation. |
| Lower-lobe posterior basal | Supported prone. A head-down tilt is used in some traditional protocols if safe and indicated. |
Historically, head-down tilt was also used for some middle-lobe, lingular and basal positions. A foot-of-bed height in centimetres does not determine a bed angle without knowing the geometry of the bed. For an appropriate stable patient, start with a tolerable position, then reassess breathing effort, oxygenation as indicated, sputum clearance, comfort and fatigue. Time the session around meals, symptoms and the patient's care plan. The British Thoracic Society suggests modified drainage without head-down tilt if standard positions are contraindicated or not tolerated in bronchiectasis. If reflux increases even with modified positions, teach a sitting technique.
When positioning requires a different plan
- Intracranial hypertension or recent neurosurgical concern. Avoid head-down tilt and maintain the position ordered by the treating team. The historical AARC drainage guideline identifies ICP above 20 mmHg among its head-down contraindications. This is a positioning precaution. The Brain Trauma Foundation's threshold above 22 mmHg is a treatment recommendation for monitored severe traumatic brain injury. It is not a clearance threshold for therapy. Review any pressure device separately. For example, the Aerobika instructions advise against its use with ICP above 20 mmHg, regardless of whether the patient is sitting.
- High aspiration risk, symptomatic reflux, or inability to tolerate lying. Reassess the position and consider a sitting option where appropriate. Ensure the person can protect the airway. Coordinate with the team if there are active feeding or swallowing concerns.
- Acute instability, significant active hemoptysis, or suspected serious thoracic injury. Stop routine treatment and arrange appropriate assessment. With acute cardiopulmonary decompensation, priority is stabilization. Review any postoperative, skeletal, bleeding or device-specific restrictions before proceeding.
2. Manual Techniques
Percussion uses rhythmic contact with a cupped hand over a suitable area of the chest wall, through light clothing or a protective layer. It can be used with positioning and active breathing or cough when appropriate. For example, a posterior basal target may use the lower posterior chest above the costal margin. Avoid direct contact over the spine, sternum, lower costal margin, wounds or other vulnerable sites. Check tissue and bone fragility, pain, bleeding risk and surgical restrictions. Select the intensity and duration according to the care plan and response.
Vibration uses a gentle oscillating chest-wall force during expiration. A small study in healthy adults measured a change in expiratory flow with vibration. A flow change does not by itself prove that mucus was moved or thinned. Use manual techniques only when they add useful, tolerable assistance. In adults with bronchiectasis, the BTS guideline includes manual assistance as an option when fatigue or an exacerbation makes independent treatment difficult.
3. Active Cycle of Breathing Techniques
| Component | How it fits the cycle |
|---|---|
| Breathing control | Take relaxed breaths at a comfortable depth and pace. Return here as needed between active efforts. |
| Thoracic expansion | Take a few deeper breaths with a relaxed exhalation. A brief inspiratory pause may be used if tolerated to allow time for gas distribution. It does not guarantee ventilation behind a complete obstruction. |
| Forced expiration technique | Take one or two open-glottis huffs as appropriate, like fogging a mirror. Use a lower or medium starting volume to help move more peripheral secretions, or a higher starting volume to clear secretions felt in larger airways. Return to relaxed breathing and cough when useful to expel mucus. |
During forced expiration, the equal pressure point is where pressure inside the airway equals pleural pressure. Toward the mouth from that point, pressure outside an intrathoracic airway may exceed pressure inside it, narrowing the airway. Starting lung volume, elastic recoil and effort influence where compression occurs. Open-glottis huffing gives a way to vary effort. It can still narrow an airway and can provoke wheeze if too forceful. Ask what the patient feels or hears, listen if needed and adjust technique. Do not assume relaxed breathing or a fixed hold prevents bronchospasm or desaturation.
4. Autogenic Drainage
Autogenic drainage uses controlled breathing at gradually increasing lung volumes. The patient learns to regulate expiratory flow and detect movement of secretions by sound or sensation. The unsticking phase uses lower lung volumes, the collecting phase uses middle volumes, and the evacuating phase uses higher volumes followed by a huff or cough as needed. Expiratory reserve volume is the size of a volume interval, not the lung volume at which the patient starts breathing. Avoid forcing expiration to residual volume. Provide instruction, check technique, and adjust the pace to comfort and clearance.
5. Devices
| Device | Principle and clinical checks |
|---|---|
| Positive expiratory pressure (PEP) | The patient exhales against resistance through a mouthpiece or mask. Backpressure can help maintain airway patency during exhalation. Set resistance using the device and clinical protocol, then use huffing or cough as needed. |
| Oscillating PEP (OPEP) | Expiratory resistance adds pressure and flow oscillations. These can assist mucus mobilization, with frequency and amplitude depending on device design, settings and flow. A Flutter device uses a ball and its tilt changes performance. Acapella uses a different mechanism that is less dependent on orientation. |
| High-frequency chest wall oscillation (HFCWO) | A powered vest repeatedly compresses the chest wall and creates airflow oscillations. Select settings and timing under the care plan and include a way to expel mobilized mucus. It is one option in cystic fibrosis. A long-term CF trial found fewer pulmonary exacerbations with mask PEP than with HFCWO. |
| Mechanical insufflation–exsufflation | Positive pressure assists inspiration, then negative pressure assists expiratory flow to augment an ineffective cough in selected patients. Use trained assessment and an individualized setup. This addresses a different problem from a device used mainly to mobilize mucus. |
For example, the Aerobika instructions start setup with the patient seated and the resistance indicator at its middle setting, then adjust resistance for an exhalation about three to four times as long as inspiration without excessive fatigue. This is a manufacturer-specific example. Read the full instructions, including restrictions for active hemoptysis, untreated pneumothorax, elevated ICP or hemodynamic instability. Check cleaning, patient technique and response. A nominal frequency near a ciliary beat rate does not establish a universal therapeutic mechanism or dose.
6. Clinical Selection
| Setting | Selection principle |
|---|---|
| Adult bronchiectasis | The 2025 ERS guideline recommends teaching individualized airway clearance. ACBT or OPEP are options. Choice depends on preference, comorbidities, tolerance and response. Some patients with dry cough and evidence of mucus plugging may also benefit. |
| Cystic fibrosis | The Cystic Fibrosis Foundation recommends airway clearance, with technique individualized. Review the current CF care plan, feasibility and patient preference. |
| Hospitalized COPD or uncomplicated pneumonia | Routine clearance therapy is not recommended for all patients. Consider it for COPD with symptomatic secretion retention when cough alone is insufficient. |
| Postoperative care | Encourage appropriate early mobility. Neither routine airway clearance nor prophylactic incentive spirometry is indicated for every patient. Investigate retained secretions, atelectasis or new respiratory compromise and tailor treatment. |
| Neuromuscular weakness | Assess ability to clear secretions and consider cough augmentation. The AARC inpatient guideline highlights peak cough flow below 270 L/min in neuromuscular disease as a context for cough assist, interpreted with clinical findings and the care plan. |
Worked Clinical Decision
A patient with stable bronchiectasis has retained secretions in the lower lobes and develops reflux when lying flat. Choose a sitting technique. Teach breathing control, thoracic expansion and tailored huffs. Reassess sputum clearance, breathlessness, effort and the patient's ability to repeat the technique independently. If the patient prefers a device and can use it safely, trial an appropriate OPEP setup and compare the response. New significant hemoptysis, a fall in oxygenation outside the agreed range or worsening respiratory distress changes the plan and warrants assessment.
In a traditional gravity-assisted drainage protocol, a stable patient is assessed for a posterior basal target. Which position illustrates the traditional approach if tilt is appropriate?
Supine with the knees supported
Supported prone with head-down tilt
Supported upright sitting
Quarter turn back from opposite-side lying
A patient with retained secretions has monitored intracranial hypertension and a head-elevated positioning order. Which proposed change should be rejected?
Keep the prescribed position while the team assesses the urgency and clearance options.
Review each proposed device’s restrictions with the respiratory team.
Lower the head and use Trendelenburg drainage to target the basal segments.
Review the patient’s airway protection and ability to clear secretions.
During active cycle of breathing, the therapist adds a short comfortable pause at the top of a deeper breath. What is the purpose of the pause?
To create a cough by suddenly closing the glottis during expiration
To replace the subsequent forced expiration technique
To establish that every obstructed region has received gas
To allow more time for gas distribution before relaxed expiration
What distinguishes an oscillating positive expiratory pressure device from a nonoscillating PEP device?
It adds pressure and flow fluctuations during resisted expiration.
It applies continuous inspiratory pressure without expiratory resistance.
It alternates positive inspiration with negative expiratory pressure to assist cough.
It provides external chest-wall compressions through an inflatable vest.
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