Respiratory Physiotherapy

Original Editor - Manisha Shrestha Top Contributors - Farah Al Dweik, Manisha Shrestha, Lucinda hampton, Chelsea Mclene, Kim Jackson, Oyemi Sillo, Rishika Babburu and Alexandra Stead

Introduction

Respiratory physiotherapy is a specialised area of physiotherapy involved in the assessment, management, and rehabilitation of people with respiratory conditions. Respiratory physiotherapists work across a variety of settings including intensive care units (ICUs), hospital wards, and outpatient and community settings. Interventions such as airway clearance techniques, pulmonary rehabilitation, and early mobilisation are used to improve respiratory function, physical activity, and quality of life.

Respiratory physiotherapy, traditionally referred to as chest physiotherapy, includes the management of excessive airway secretions, optimisation of lung volumes, preservation of musculoskeletal function, and patient education. It is used in a wide range of conditions including chronic respiratory diseases (such as bronchiectasis and cystic fibrosis), neuromuscular disorders, and peri-operative care particularly following upper abdominal surgery.

Aims of Respiratory Physiotherapy

Respiratory Tract with increased mucus.

The aims of respiratory physiotherapy include:

• Assisting with the clearance of retained airway secretions.
• Improving ventilation and gas exchange.
• Reducing the work of breathing.
• Improving exercise tolerance and physical activity.
• Preventing secondary complications associated with respiratory dysfunction and reduced mobility.
• Supporting recovery through pulmonary rehabilitation and patient education.

The Physiological Mechanism of Airway Clearance

Ciliated epithelium, bronchus with short microvilli on non-ciliated cells

Normal Airway Clearance

Normal airway clearance requires an open airway, a functional mucociliary escalator, and an effective cough. Airways are maintained by structural support mechanisms and kept clear by the normal function of the ciliated mucosa. The human bronchial tree is lined by a thin mucus layer (approximately 5 μm) which is transported towards the upper respiratory tract by coordinated ciliary action. Secretions reaching the trachea and larynx can then be swallowed or expectorated.

An effective cough is also essential for maintaining airway clearance. By removing excessive mucus and foreign material, coughing assists normal mucociliary clearance and helps ensure airway patency. A normal cough consists of four phases: irritation, inspiration, compression, and expulsion.

Abnormal Airway Clearance

The interaction between airflow and mucus within the tracheobronchial tree is complex because of the branching geometry of the airways, collapsible airway walls, changing airflow velocity, and the viscoelastic properties of mucus. This mechanism is described as a two-phase gas–liquid flow. In endobronchial diseases, the mucus layer may exceed 5 mm in thickness and ciliary clearance becomes ineffective. Under these conditions, two-phase flow becomes an important mechanism of secretion clearance. At a particular combination of airflow, mucus viscosity, and mucus thickness, strong gas–liquid interactions first exacerbate the pressure decrease and then detach mucus from the airway wall. This process narrows the airway lumen, increases resistance, and further impairs airway clearance.

One mechanism by which coughing assists sputum clearance in endobronchial diseases is through two-phase gas–liquid flow, allowing transfer of momentum and energy from high-velocity airflow to airway secretions. However, the high transmural pressures generated during coughing may produce dynamic airway compression and inhibit mucociliary clearance. Forced expiratory technique (FET) was introduced to address this problem.

Classification of Airway Clearance Techniques

Respiratory physiotherapy includes a variety of interventions used to support airway clearance and respiratory function. These techniques can be classified as conventional, modern, or instrumental, based on evolving research.

Conventional Techniques

Conventional chest physiotherapy, also referred to as traditional chest physiotherapy, was first described in 1915. It involves manual techniques aimed at facilitating mucociliary clearance. Postural drainage, percussion, and vibration (PDPV) were previously the most widely recognised form of chest physiotherapy, with coughing exercises and forced expiratory techniques (huffing) added later. PDPV may be self-administered or performed with the assistance of a physiotherapist or caregiver. Common conventional techniques are summarised in Table 1.

Table 1. Conventional Airway Clearance Technique

Technique	Description	Contraindications and Precautions
Postural drainage	Uses gravity-assisted positioning to help move secretions from specific lung segments towards the central airways, where they can be cleared by coughing or suctioning. Positions should be selected based on clinical assessment, auscultation findings, and patient tolerance.	Raised intracranial pressure (>20 mmHg) Recent head or spinal injury Active haemorrhage with haemodynamic instability Pulmonary embolism Large pleural effusions or pulmonary oedema Rib fractures or surgical wounds Inability to tolerate position changes Additional precautions are required with Trendelenburg positioning in individuals with uncontrolled hypertension, recent neurosurgery, oesophageal surgery, or risk of aspiration
Percussion	Also called cupping or clapping. It involves rhythmic application of a cupped hand or mechanical device over the chest wall to help loosen airway secretions.	Subcutaneous emphysema Burns, open wounds, or recent skin grafts of the thorax Chest wall pain or lung contusion Osteoporosis or coagulopathy Bronchospasm Recently inserted pacemaker
Vibration	Involves manual or mechanical oscillatory pressure applied during expiration to assist movement of secretions towards larger airways.	Similar precautions to percussion should be considered Pain or unstable rib fractures Osteoporosis Recent thoracic surgery
Coughing	Includes directed coughing and assisted coughing techniques to support secretion clearance.	Active haemoptysis Raised intracranial pressure or known intracranial aneurysm Reduced coronary artery perfusion (e.g. acute myocardial infarction) Unstable head, neck, or spine injury
Forced expiratory technique (FET)	Also known as huffing. It involves forced expiration through an open glottis from mid to low lung volumes and is often used to move secretions while reducing excessive airway compression compared with repeated coughing.	Active haemoptysis Uncontrolled bronchospasm Raised intracranial pressure or recent eye, intracranial, or spinal surgery

Clinical Considerations

Conventional airway clearance techniques are indicated in the presence of:

• Sputum production greater than 25–30 mL/day in adults, or difficulty clearing secretions independently.

• Reduced cough effectiveness.
• Retained secretions in the presence of an artificial airway.
• Atelectasis caused by, or suspected to be caused by, mucus plugging.
• Conditions associated with excessive secretion production, such as cystic fibrosis and bronchiectasis.

Treatment frequency should be individualised according to the person's respiratory status and clinical response.

Modern Airway Clearance Techniques

Over the years, several non-invasive airway clearance techniques have been developed to complement conventional chest physiotherapy. These approaches use breathing control and variations in airflow to facilitate secretion clearance. Common modern techniques include the active cycle of breathing technique (ACBT) and autogenic drainage.

Table 2. Modern Airway Clearance Techniques

Technique	Description	Precautions
Active Cycle of Breathing Technique (ACBT)	ACBT is an active breathing technique performed by the patient to mobilise and clear pulmonary secretions and improve ventilation. It consists of three phases: breathing control, thoracic expansion exercises, and forced expiratory technique (FET).	Undrained pneumothorax or subcutaneous emphysema Active or recent haemoptysis Unstable rib fracture or osteoporosis Lung contusion Patients unable to follow instructions or not spontaneously breathing
Autogenic Drainage	Autogenic drainage is a controlled breathing technique used to mobilise secretions from different levels of the airways. It combines breathing at different lung volumes with breath control and delayed coughing to facilitate mucus clearance. It is commonly used in individuals with cystic fibrosis and bronchiectasis.	Active or recent haemoptysis Undrained pneumothorax Patients unable to cooperate with or learn the technique, as it requires training and concentration.

Instrumental Airway Clearance Techniques

Instrumental airway clearance techniques may be used as an adjunct to conventional airway clearance methods and to provide respiratory support. Common instrumental techniques are summarised in Table 3.

Table 3. Instrumental Airway Clearance Techniques

Technique	Description	Precautions
Positive Expiratory Pressure (PEP)	PEP devices provide resistance during expiration through a mouthpiece or facemask. These devices help remove secretions by increasing functional residual capacity and enhancing collateral ventilation. Common examples include Flutter, Acapella, and Lung Flute devices.	Untreated pneumothorax Raised intracranial pressure (>20 mmHg) Active haemoptysis Recent trauma or surgery to the skull, face, mouth, or oesophagus Acute asthma exacerbation or chronic obstructive pulmonary disease (COPD) exacerbation with intolerance to increased work of breathing
Continuous Positive Airway Pressure (CPAP)	CPAP generates positive end expiratory pressure (PEEP) to help maintain airway patency and improve oxygenation. It may be delivered using nasal prongs or a face mask. Bubble CPAP can also be used in low-resource settings and in the paediatric population.	Facial trauma or recent facial/upper airway surgery Haemodynamic instability Active vomiting or inability to protect the airway Base of skull fracture
High-Frequency Chest Wall Oscillation (HFCWO)	HFCWO uses an inflatable vest connected to a pulse generator to deliver oscillations to the chest wall. The generator rapidly inflates and deflates the vest at different frequencies and intensities, producing vibrations that help loosen mucus from the airway walls and move secretions towards the larger airways for clearance. HFCWO typically operates at frequencies ranging from 5 to 25 Hz and is usually interrupted periodically to allow coughing and expectoration of loosened secretions.	Active or recent haemoptysis Unstable rib fractures or chest wall trauma Untreated pneumothorax Recent thoracic or abdominal surgery Subcutaneous emphysema
Intrapulmonary Percussive Ventilation (IPV)	IPV is designed to promote mobilisation of bronchial secretions and improve the efficiency and distribution of ventilation. It uses a pneumatic device to deliver high-frequency bursts of pressurised gas to the respiratory tract while maintaining positive airway pressure. This provides intrathoracic percussion and vibration to assist secretion clearance.	Haemodynamic instability Active haemoptysis Raised intracranial pressure Bullous lung disease

Assessment

Assessment findings should be considered together when determining the need for respiratory physiotherapy. These may include:

Symptoms and Medical History

Relevant symptoms and medical history may include:

• Excessive sputum production.
• Patient-reported symptoms such as dyspnoea, chest tightness, or sleep disturbance related to secretions.
• Previous respiratory conditions that responded to airway clearance techniques, such as bronchiectasis, cystic fibrosis, or lung abscess.

Physical Examination Findings

Physical examination findings may include:

• Reduced cough effectiveness.
• Reduced breath sounds, crackles, or rhonchi suggesting retained secretions.
• Changes in vital signs.

Physiological and Investigative Findings

Additional physiological and investigative findings may include:

• Chest X-ray findings consistent with atelectasis, mucus plugging, or infiltrates.
• Changes in arterial blood gas values or oxygen saturation.

Outcome Measures

Response to treatment should be assessed using both objective and subjective outcome measures. These may include:

Clinical Outcome Measures

Common physiological outcome measures include:

• Changes in sputum volume or viscosity.
• Changes in breath sounds.
• Changes in vital signs.
• Changes in arterial blood gas values or oxygen saturation.
• Changes in ventilator parameters where applicable.
• Peak Expiratory Flow Rate.
• Pulmonary function tests and lung volumes where available.

Functional Measures

Functional outcome measures may include:

• Six-Minute Walk Test or other measures of functional exercise capacity.
• Incremental Shuttle Walk Test (ISWT), used to assess functional exercise capacity and response to rehabilitation.
• Borg Rating of Perceived Exertion or oxygen desaturation during exercise testing.

Patient-Reported Outcomes

Patient-reported outcome measures may include:

• Patient-reported response to treatment.
• Modified Borg Scale for dyspnoea.
• Quality of life

Conclusion

Selection of an airway clearance technique should be guided by the person's respiratory condition, secretion load, ability to participate actively, and any contraindications or precautions. Conventional techniques remain widely used and evidence-based, while modern and instrumental techniques provide additional options for individuals who are unable to tolerate or benefit from manual techniques. As no single outcome measure is considered a gold standard, a combination of physiological measures and patient-reported outcomes should be used to monitor treatment effectiveness.