PHYSIOTHERAPY TECHNIQUIES IN RESPIATROY

COUGH

A cough consists of a deep inspiration followed by a forced expiratory manouvre performed against a closed glottis. This results in a rapid rise in intrathoracic pressure. As the glottis opens the pressure difference between the small airways and the trachea results in a rapid flow of air. High airflow augmented with dynamic compression of airways results in shearing of the mucus layer and mist flow through gas liquid interaction.
 
Indications

•      Upper or large airways secretions. Cough is thought to be effective in clearing secretions from the larger airways up to the seventh generation of bronchi. Dynamic airway compression by high intrathoracic pressures limits cough effectiveness in small or overcompliant airways.

•      Vigorous coughing (11 times over 10 minutes) has been shown to be comparable to postural drainage+percussion in rate and quantity of sputum clearance.

Cough may be impaired by inadequate lung volume, incomplete glottic closure, respiratory muscle weakness/general fatigue, pain.

Precautions


Subcutaneous emphysema/ untreated pneumothorax
Raised ICP
Recent eye surgery
Paroxyms of coughing may lead to fatigue, bronchospasm, airway closure, hypoxia.

Huff

A huff is a forced expiratory manouvre performed with an open glottis, resulting in lower intrathoracic pressures than a cough. The position of the EPP produced by huffing can be manipulated by varying the lung volume at which the huff is commenced. Mid lung volume huffs produce EPP within lobar and segmental bronchi; low volume in peripheral airways.

Indications
Peripheral or small airways secretions. Children from the age of three years can be taught to huff

Precautions

Similar to cough if vigorous or prolonged to the point of uncontrolled coughing.

Forced Expiration Technique ( FET )

The forced expiration technique is defined as 1 2 huffs from mid to low lung volume followed by a period of relaxed controlled breathing. The forced expiration technique utilizes the physiology of the huff combined with a recovery phase to reduce the possibility of airway closure, desaturation or fatigue. Breathing control (Webber 1988), is gentle breathing with normal tidal volume and rate, using the lower chest. Relaxation of the upper chest and shoulders is encouraged, expiration is unforced.

Active Cycle of Breathing Technique (ACBT)

The FET is an integral part of the Active Cycle of Breathing Technique described by Pryor and Webber in 1992. The authors felt that the FET required expansion because clinically breathing control was underutilized and the link between breathing exercises and FET poorly understood.

The Active Cycle of Breathing Technique comprises; relaxed breathing control, thoracic expansion exercises, forced expiration technique.

Thoracic expansion exercises recruit the collateral ventilatory system assisting, the movement of air distal to mucus plugs in the peripheral airways. Increasing tidal volume also utilizes the interdependence or mutual force of adjacent alveoli to re expand collapsed alveoli. The ACBT combines airway clearance with the promotion of ventilation. Extensive evidence supports its effectiveness in sitting or gravity assisted positions. A minimum of ten minutes in each productive position is recommended. The ACBT may be performed with or without an assistant providing vibration, percussion and shaking. Self percussion/compression may be included by the patient.

POSTURAL DRAINAGE

Postural drainage aims to move secretions by gravity from areas distal to segmental bronchi into larger airways where mucociliary clearance, huff and cough will result in expectoration. 11 postural drainage positions were first described by Nelson in 1934 based on the anatomy of the bronchial tree. Each position aims to vertically place the draining bronchus or bronchopulmonary segment above the trachea to drain under the influence of gravity. Positions may require modification if lung architecture has been distorted by surgery, fibrosis, abscess etc.

Literature suggests that gravity may not be the only mechanism involved. Lanefors (1992) found greater clearance from the dependent lung during postural drainage. This was believed to be due to greater ventilation in dependent regions encouraging movement of secretions by high flows and mechanical squeezing. NB very thick secretions defy gravity in sputum cups.

A minimum of 10 minutes is recommended with 3 4 positions in a treatment session. The worst area is drained first to reduce the chance of infected secretions spilling into healthy lung. The head down position increases the work of breathing, reduces tidal volume and FRC even in healthy individuals thus positions may require modification to flat or head up positions in breathless patients.

Indications

• Production of more than 30ml of sputum per day.

• Secretions unable to be removed by forced expiratory manouvres and manual techniques.

• Patient preference, greater effectiveness than other methods.

Precautions (majority relate to tipping the patient head down)

Raised intracranial pressure, severe hypertension, immediately following oesophageal surgery, recent pneumonectomy, bronchopleural fistula, aortic aneurysms pulmonary oedema, cardiac arrythmias, cardiac failure,  severe subcutaneous emphysema, untreated pneumothorax epistaxis or recent haemoptysis, hiatus hernia and gastro oesophageal reflux conditions resulting in increased abdominal pressure and restricted diaphagmatic descent (pregnancy, ascites), eye surgery (recent surgery to head/neck)
 Manual Techniques : Vibration and Shaking

Vibration and shaking are techniques that consist of intermittent chest wall compression performed throughout the expiratory phase of breathing. Both techniques are performed immediately over the area of secretions. The intermittent compression is thought to reinforce the expiratory flow of gas from the lungs, thereby increasing, the shearing action on the mucosal layer. Vibration is a less intense form of chest shaking. Vibrations are performed using the therapist's hands and arms to create oscillations of small amplitude and high frequency while shaking utilises the therapist's, arms and body to create oscillations of large amplitude and lower frequency.

Indications 0 Retained secretions that are not effectively cleared by forced expiratory manouvres.

Percussion (chest clapping)

Percussion is the rhythmic "clapping" of cupped hands over the area of retained secretions. It may be performed by an assistant or independently by the patient. This technique is thought to produce an energy wave which is transmitted through the chest wall causing turbulence and compression of air within the airways. This in turn causes vibration and consequent loosening of secretions which may be cleared by additional techniques. Percussion is not intended to Simulate the skin or be painful.

Percussion combined with postural drainage has been likened to emptying a ketchup bottle in the literature. Research has demonstrated increased rate and case of sputum expectoration others show PD and FET equally effective without percussion.

Declines in oxygen saturation have been documented in the presence of prolonged percussion without thoracic expansion exercises. Zidulka et al (1989) demonstrated continuous percussion resulted in sianificant atelectasis in dogs. It was postulated that percussion may increase the rate of air movement out of the alveolus thus resulting in altered surfactant and increased atelectasis.

Indications
• Excessive pulmonary secretions that cannot be cleared by forced expiratory manouvres.
• Can be used to stimulate cough and deep breathing in young children and the unconscious patient.

Precautions for manual techniques

Severe haemoptysis, Clotting disorders (platlet count < 150 X 109/L), acute pleuritic pain rib fracture or conditions resulting in decreased bone density (metastatic cancer, osteoporosis), loss of skin integrity (surgery, bums, wounds, skin flaps/grafts), acute cardiac conditions,subcutaneous emphysema acute respiratory distress, unrelated to retained secretions (eg pulmonary oedema), tumours (where signs are due to airway blockage, or associated risk of rib metastasis/haemoptysis)

Positive Expiratory Pressure

The application of resistance to expiratory flow is thought to;

•      limit compression of compliant airways,

•     facilitate collateral airflow between ventilated and atelectatic alveoli as gas equalizes through the pores of Kohn, thus generating flow behind obstruction to expel mucus blocking the airway (evidence of collateral floe by Anderson et al 1979 in cadaver lungs)

Application

In sitting or postural drainage position, delivered via facemask or mouthpiece with a one way valve and
expiratory resistor.                                                                                        
Expiratory pressure= 10 20cmH20 during the middle phase of exhalation.
Breaths are of tidal volume or slightly larger but not to lung capacity, with a slightly active exhalation to
FRC. The ratio of inspiration to exhalation =1:3   1:4.
Number of breaths = 5 20, many report 10 20 breaths repeated 4 6 times for a treatment duration of 10 20 mins. PEP can be utilized in the ACBT thoracic expansion phase.

Other considerations
Age of  3 upwards. Need to check pressure regularly and adjust resistor /technique. Evidence suggests equivalent to other techniques, some suggest not as effective as conventional treatment in large sputum producers. Favorable reports regarding compliance and individual adaptability.

Indications

• Secretion retention in patients with unstable or compliant airways.

• Patients seeking freedom from postural drainage and assistance who prefer the upright posture for treatment, or where postural drainage and/or manual techniques are contra indicated.

Precautions

untreated pneumothorax
severe haemoptysis
facial fractures/surgery
sinusitis or ear problems
hyper reactive airways.

High pressure PEP 26 102cmH20, variable reports of effectiveness in the literature. Requires closer monitoring., one documented case of pneumothorax, one of massive haemoptysis.

Flutter
The patient exhales into the device against a resistance (5 20cmH2O) generated by a ball covering the opening of an enclosed upward and widening cone. The movement of the ball during expiration creates an oscillating frequency between 8 26Hz

Theoretical Physiology

Incorporates        positive expiratory pressure (adjusted by flowrate)
-          oral high frequency oscillation (angle of device)
-          active breathing exercises.
 Oscillating positive pressure prevents early airway collapse. The rhythmic variation of airway diameter and airflow promotes mucus mobilization. Oscillation approximates the cilia 'beat' frequency of 12Hz.

Application

Instructions say practice 2 3 times daily for 3 10 minutes. Take a deep breath with a 2 3 second hold then exhale fully adjusting the angle and flowrate to attain optimal vibration. Perform 5 15 then increase the depth of breath and speed of exhalation to precipitate cough and mucus expectoration. The Flutter can be incorporated into the ACBT during the thoracic expansion phase, but is difficult to combine with postural drainage. Appears to be less effective than
postural drainage and manual techniques in large sputum producers.

Indications

Retained secretions (particularly if sticky)
Patients seeking freedom from postural drainage and assistance who prefer the upright posture for treatment, or where postural drainage and/or manual techniques are contra indicated.
Good for children, stimulates cough.

Precautions

Similar to those for PEP  untreated pneumothorax, severe haemoptysis, facial fractures/surgery, sinusitis or ear problems. Some clients report early uncontrolled coughing particularly in the presence of hyper reactive airways

Autogenic Drainage

" Self drainage" developed in Belgium in the late 1960's by Chevaillier (asthmatic patients). During 1980's utilized throughout Europe to treat patients with retention of secretions.


Theoretical Physiology

Utilizes expiratory airflow to mobilize secretions, aim to reach the highest possible airflow in the different generations of bronchi by controlled breathing. Aim to avoid compression of the airways by high flow peaks, which cause collapse at the EPP, trying to produce a mucus rattle rather than a wheeze. Thus find a balance between expiratory forces and stability of the bronchial wall.

Application

The patient is trained to breathe at three different lung volumes or phases
1st phase   unstick peripheral mucus at low lung volume (ERV)
2nd phase   collect from central airways, low to mid lung volume (ERV TV)
3rd  phase   evacuate from central airways, mid to high lung volume (TV  IRV) All phases are performed with tidal breathing with an inspiratory hold for 2 3 seconds to allow equalization and thus uniform expiratory flow.

Other Considerations
Generally done in sitting but can use postural drainage positions. Independent technique, unwell patients can become fatigued. Treatment time 30 40mins up to one how. Autogenic drainage takes 10 20hrs to learn from trained staff, earliest age 8 12yrs. ? can all patients localize secretions, do all patients have unstable airways.

Indication

Secretion retention in patients with unstable or compliant airways.
Patients seeking freedom from postural drainage and assistance who prefer the option of upright posture
Particularly useful in patients who are skilled in secretion localization
Patients older than 8yrs who have the concentration to learn the technique.

Precautions
Generally considered to require more effort and concentration than other techniques.