Respiratory Physiotherapy

Original Editor - Manisha Shrestha Top Contributors - Manisha Shrestha, Lucinda hampton, Chelsea Mclene, Kim Jackson, Oyemi Sillo and Rishika Babburu

Description

Chest physiotherapy is a broad term used in research that incorporates physiotherapy treatment techniques that address the removal of secretion and improve airway clearance thereby help to improve respiratory efficiency. Chest physiotherapy is the term for a group of treatments designed to eliminate secretions thus helps to decrease work of breathing, promote the expansion of the lungs, and prevent the lungs from collapse.

It is different from bronchial hygiene therapy (BHT) in a way that BHT incorporate chest physiotherapy along with breathing exercises and manual hyperventilation in an intubated patient. Bronchial hygiene involves the use of noninvasive airway clearance techniques designed to help mobilize and remove secretions and improve gas exchange.

Chest physiotherapy is the important adjuvant treatment of most respiratory illnesses from chronic respiratory illness ( COPD, bronchiectasis, cystic fibrosis), neuromuscular diseases (muscular dystrophy, cerebral palsy, spinal cord injury), and during peri-operative care mainly in upper abdominal surgeries. Chest physiotherapy can be a valuable component of comprehensive respiratory care but only if used when indicated.

Aim of Chest Physiotherapy

The purpose of chest physiotherapy are:

• To facilitate removal of retained or profuse airway secretions.
• To optimize lung compliance and prevent it from collapsing.
• To decrease the work of breathing.
• To optimize the ventilation-perfusion ratio/ improve gas exchange.

The Physiological Mechanism of Airway Clearance

Normal Clearance

A normal clearance requires an open airway, a functional mucociliary escalator, and an effective cough. Airways normally are kept open by structural support mechanisms and kept clear by the proper function of their ciliated mucosa. The normal human bronchial tree is lined by a thin (5 micrometers) layer of mucus which is moved over the airway surface by the mucociliary escalator. The ciliated epithelium which lines the airways is responsible for the continuous flow of mucus over the airway surface to the upper respiratory tract. Mucus is moved via a coordinated movement of ciliary motion toward the trachea and larynx, where excess secretions can be swallowed or expectorated.

The effective cough is a must for normal airway clearance.

Cough is one of the most important protective reflexes. By ridding the larger airways of excessive mucus and foreign matter, the cough assists the normal mucociliary clearance and helps ensure airway patency. There are four distinct phases to a normal cough: irritation, inspiration, compression, and expulsion.

Abnormal Clearance

The flow of air through the tracheobronchial tree and its interaction with the mucus lining is complex because of the branching geometry of the airways, collapsible airway walls, constantly changing the velocity of airflow, and varying viscoelastic properties of mucus. This physiology of flow in liquid line airway is called a two-phase gas-liquid flow. In endobronchial diseases, the mucus layer may exceed 5 mm in thickness and ciliary clearance becomes ineffective. Two-phase flow now becomes an important mechanism of clearance, and at a particular combination of airflow, mucus viscosity, and thickness there is a very strong gas-liquid interaction which first exacerbates the pressure decrease then detaches liquid from the airway wall. this leads to the narrowing of the lumen of the tube causing a much greater resistance, thus affect airway clearance.

One of the mechanisms by which cough affects sputum clearance in endobronchial diseases is two phases gas-liquid flow: the transfer of momentum and energy from the high-speed flow of air to the mucus that lines the bronchi. The high transmural pressure produced during cough leads to dynamic compression of the airway inhibiting mucociliary clearances. Thus, forced expiratory technique (FET) was introduced to solve this problem.

Classification

There are various physiotherapy treatments incorporated within chest physiotherapy. Chest physiotherapy techniques can be classified as conventional, modern, and instrumental techniques based on evolving research.

A. Conventional Techniques

Conventional chest physiotherapy is also known as traditional chest physiotherapy. It was advocated first in 1915. It involves manual handling techniques to facilitate mucociliary clearance. Postural drainage along with percussion and vibration ( PDPV) was previously widely named as Chest Physiotherapy. Later, coughing exercise, and forced expiratory techniques (huffing) was incorporated within it. PDPV with huffing had shown an effective outcome. It can be self-administered or performed with the assistance of another person (a physiotherapist, parent, or caregiver). PDPV works better if applied with bronchodilator therapy.

1. Postural drainage

Postural drainage involves the positioning of the child with the assistance of gravity to aid the normal airway clearance mechanism. Postural drainage positioning varies based on specific segments of the lungs with a large amount of secretions. Postural drainage is the drainage of secretions, by the effect of gravity, from one or more lung segments to the central airways (where they can be removed by a cough or mechanical aspiration). Each position consists of placing the target lung segment(s) superior to the carina. Positions should generally be held for 3 to 15 minutes (longer in special situations). Standard positions are modified as the patient's condition and tolerance warrant. Before determining the postural drainage position, it is very important to auscultate the lungs and identify the lung segments where added sound (Crepitus, Ronchi) is heard. Postural drainage can be facilitated with percussion and vibration in the postural drainage position.

2. Percussion

Percussion is also referred to as cupping, clapping, and tapotement. The purpose of percussion is to intermittently apply kinetic energy to the chest wall and lungs. This is accomplished by rhythmically striking the thorax with a cupped hand or mechanical device directly over the lung segment(s) being drained. 

3. Vibration

Vibration involves the application of a fine tremorous action (manually performed by pressing in the direction that the ribs and soft tissue of the chest move during expiration) over the draining area. In this technique, a rapid vibratory impulse is transmitted through the chest wall from the flattened hands of the therapist by isometric alternate contraction of forearm flexor and extensor muscles, to loosen and dislodge the airway secretions.

4. Coughing

Directed coughing or various assisted coughing are incorporated within it.

5. Forced Expiratory Technique (FET)

Forced expiratory techniques involve diaphragmatic inspiration, relaxing the scapulohumeral region, and expiring forcefully from mid to low lung volumes whilst maintaining an open glottis ("huffing" exercises). It is effective than that of coughing.

Indication of Conventional techniques

Postural drainage positioning

• Inability or reluctance of the patient to change body position. (eg, mechanical ventilation, neuromuscular disease, drug-induced paralysis).
• Poor oxygenation associated with the position (eg, unilateral lung disease).
• Potential for or presence of atelectasis.
• Presence of artificial airway.

PDPV

• Difficulty clearing secretions with expectorated sputum production greater than 25-30 mL/day (adult).
• Evidence or suggestion of retained secretions in the presence of an artificial airway.
• Presence of atelectasis caused by or suspected of being caused by mucus plugging.
• Diagnosis of diseases such as cystic fibrosis, bronchiectasis, or cavitating lung disease
• Presence of foreign body in the airway.
• Patient with copious sputum or with central consolidation.

Contraindication of Conventional Techniques

Positioning

All positions are contraindicated for:

• Intracranial pressure (ICP) > 20 mm Hg
• head and neck injury until stabilized (Absolute)
• Active hemorrhage with hemodynamic instability (Absolute)
• Recent spinal surgery (eg, laminectomy) or acute spinal injury
• Acute spinal injury or active hemoptysis
• Empyema
• Bronchopleural fistula
• Pulmonary edema associated with congestive heart failure
• Large pleural effusions
• Pulmonary embolism
• Aged, confused, or anxious patients who do not tolerate position changes
• Rib fracture, with or without flail chest
• Surgical wound or healing tissue

Trendelenburg position is contraindicated for

• Intracranial pressure (ICP) > 20 mm Hg
• Patients in whom increased intracranial pressure is to be avoided (eg, neurosurgery, aneurysms, eye surgery)
• Uncontrolled hypertension
• Distended abdomen
• Oesophageal surgery
• Recent gross hemoptysis related to recent lung carcinoma treated surgically or with radiation therapy.
• Uncontrolled airway at risk for aspiration (tube feeding or recent meal)

Reverse Trendelenburg is contraindicated in the presence of hypotension or vasoactive medication.

External Manipulation of the Thorax

In addition to contraindications previously listed

• Subcutaneous emphysema.
• Recent epidural spinal infusion or spinal anesthesia.
• Recent skin grafts, or flaps, on the thorax.
• Burns, open wounds, and skin infections of the thorax.
• Recently placed transvenous pacemaker or subcutaneous pacemaker (particularly if mechanical devices are to be used).
• Suspected pulmonary tuberculosis.
• Lung contusion.
• Bronchospasm.
• Osteomyelitis of the ribs.
• Osteoporosis.
• Coagulopathy.
• Complaint of chest-wall pain.

Complications

• Hypoxemia
• Bronchospasm
• Increased Intracranial Pressure
• Acute Hypotension during Procedure
• Pulmonary Hemorrhage
• Pain or Injury to Muscles, Ribs, or Spine
• Vomiting and Aspiration
• Bronchospasm
• Dysrhythmias

Frequency

Positioning

Ventilated and critically ill patients: as necessary with the goal of once each hour or every other hour as tolerated, around the clock. Less acute patients should be turned every 2 hours as tolerated.

PDPV

• In critical care patients, including those on mechanical ventilation, PDT should be performed every 4 to every 6 hours as indicated. PDT order should be re-evaluated at least every 48 hours based on assessments from individual treatments.
• In spontaneously breathing patients, frequency should be determined by assessing patient response to therapy.
• Acute care patient orders should be re-evaluated based on patient response to therapy at least every 72 hours or with a change of patient status.
• Domiciliary patients should be re-evaluated every 3 months and with a change of status.

B. Modern techniques

Over the years, several additional noninvasive clearance methods have been developed to augment this traditional approach. Modern techniques use a variation of flow through breath control to mobilize secretions. It includes an active cycle of breathing and autogenic drainage.

1. Active cycle of breathing technique

Active cycle of breathing technique (ACBT) is an active breathing technique performed by the patient, and can be used to mobilize and clear excess pulmonary secretions and to generally improve lung function. It has a series of three main phases: Breathing control, Thoracic expansion, and Forced expiratory technique.

2. Autogenic drainage

Autogenic drainage is a three‐phase active breathing technique using high expiratory flow rates and variable lung volumes to unstick, collect, and evacuate secretions. The recipient is placed sitting, back straight, and head slightly hyperextended, hands resting on the upper left and right chest. The recipient first breathes at a low lung volume to unstick secretions in the peripheral airways, then at mid‐volume to collect secretions in the central airways, and finally breathes at high volume to clear secretions from the lungs. Autogenic drainage is potentially advantageous because it improves independency. No equipment is needed, and it is applicable in different settings and in daily life. The three phases of autogenic drainage are as follows.

• Displacement: starts with a slow and forced oral expiration, recruiting a percentage of expiratory reserve volume, and then carrying inspiration to low volume, recruiting percentages of tidal volume followed by a two‐ to three‐second post-inspiratory pause. This is followed by a slow oral exhalation recruiting a percentage of expiratory reserve volume.
• Collection: nasal inspiration to medium volume, recruiting a larger percentage of tidal volume, followed by a two‐ to three‐second post-inspiratory pause. This is followed by a slow oral exhalation recruiting a percentage of expiratory reserve volume.
• Elimination: nasal inspiration to high volume recruiting tidal volume and a percentage of inspiratory reserve volume, followed by a two‐ to three‐second post-inspiratory pause, leading to oral expiration at the level of tidal volume. The forced expiration technique is performed to high volumes.

C. Instrumental techniques

Instrumental techniques such as non‐invasive ventilation have been considered useful as an adjunct therapy to airway clearance and to provide respiratory support. A common instrumental technique are:

1. Positive expiratory pressure (PEP)

There are various positive expiratory pressure devices that provide resistance to expiration through a mouthpiece or facemask, followed by forced expirations. The inhalation is at tidal volume, and the expiration is slightly active against devices. These devices help to remove secretions by increasing functional residual capacity and thus enhancing collateral ventilation and removing secretions from collapse airways. Some of the devices are Flutter, Acapella, lung flute, etc.

2. Continuous Positive Airway Pressure

Continuous positive airway pressure (CPAP) is generated by exhalation against a constant opening pressure; this produces positive end‐expiratory pressure (PEEP). Continuous positive airway pressure can also be delivered by commercially available pressure drivers. These generally require tightly fitting nasal prongs or a CPAP facemask. Bubble CPAP can be used in a low resource environment and in the pediatric population. It consists of an interface (nasal cannula), inspiratory tubing, and expiratory tubing immersed in an underwater bottle system.

3. High-Frequency Chest Wall Oscillation (HFCWO)

High-frequency chest wall oscillation (HFCWO) is an airway clearance technique in which external chest wall oscillations are applied to the chest using an inflatable vest that wraps around the chest. These machines produce vibrations at variable frequencies and intensities, helping to loosen and thin mucus and separate it from airway walls.

HFCWO involves an inflatable jacket that is attached to a pulse generator by hoses that mechanically enable the equipment to perform at variable frequencies (5–25 Hz). The generator sends air through the hose, which causes the vest to inflate and deflate rapidly. The vibrations not only separate mucus from the airway walls but also help move it up into the large airways. Typically, it is paused during the 20- to 30-minute HFCWO treatment every 5 minutes to cough out loosened mucus that has moved into the large airways.

4. Intrapulmonary Percussive Ventilation (IPV)

IPV was designed to promote mobilization of bronchial secretions and improve efficiency and distribution of ventilation, providing intrathoracic percussion and vibration and an alternative system for the delivery of the positive pressure to the lungs.  Each IPV session lasted fifteen minutes and was performed twice a day (morning and afternoon). Intrapulmonary percussive ventilation uses a pneumatic device to deliver a series of pressurized gas minibursts at rates of 100 to 225 cycles per minute to the respiratory tract, by a mouthpiece. The duration of each percussive cycle is manually controlled by a thumb button. During the cycle, constant PAP is maintained at the airway. It also incorporates nebulizer for the delivery of the aerosol.

Assessment of need and outcome

The following should be assessed together to establish a need for chest physiotherapy:

• Excessive sputum production.
• Effectiveness of cough.
• History of pulmonary problems treated successfully with PDT (eg, bronchiectasis, cystic fibrosis, lung abscess).
• Decreased breath sounds or crackles or rhonchi suggesting secretions in the airway.
• Change in vital signs.
• Abnormal chest x-ray consistent with atelectasis, mucus plugging, or infiltrates.
• Deterioration in arterial blood gas values or oxygen saturation.

The following can be used as an outcome tool to determine the effectiveness of treatment:

• Change in sputum production.
• Change in breath sounds of lung fields.
• Patient subjective response to therapy.
• Change in vital signs.
• Change in chest x-ray.
• Change in arterial blood gas values or oxygen saturation.
• Change in ventilator variables.
• Change in Modified borg scale- dyspnea level.
• Change in Peak Expiratory Flow Rate.

Resources

• Huffing – The Forced Expiration Technique (FET)