Chapter 5 Physiotherapy in intensive care
Historically, physiotherapy in the intensive care unit (ICU) was confined to the treatment of respiratory problems performed routinely on all patients. Evidence-based practice has demonstrated that there is no longer a place for routine physiotherapy treatment in ICU.1 Physiotherapeutic intervention is based on clinical reasoning following the identification of physiotherapy-amenable problems, which are elucidated from a thorough systematic assessment.
There is still some debate about the precise role of the physiotherapist within ICU, which may vary,2 but the main features include:
CARDIOPULMONARY PHYSIOTHERAPY
TREATMENT MODALITIES TO OPTIMISE CARDIOPULMONARY FUNCTION
Patients who are critically ill may present with impaired cardiopulmonary physiology secondary to both the underlying pathology and the therapeutic interventions employed to treat them. In their approach to any individual patient, physiotherapists may use specific treatment techniques targeted at improving ventilation/perfusion (V/Q) disturbances, increasing lung volumes, reducing the work of breathing and removing pulmonary secretions. Physiotherapy treatment modalities may differ depending on the presence of an endotracheal tube, although patient participation with treatment is encouraged and promoted at the earliest point during intubation. Each intervention is rarely used in isolation, but as part of an effective treatment plan. Some physiotherapeutic techniques may have short-lived beneficial effects on pulmonary function, and some have no clear evidence to validate their effectiveness (Table 5.1).
Table 5.1 Treatment modalities to optimise cardiopulmonary function
| Invasively ventilated patients | Non-invasive/self-ventilating patients |
|---|---|
| Manual hyperinflation (MHI) | Active cycle of breathing technique (ACBT) |
| Suction | Manual techniques |
| Manual techniques | Positioning |
| Positioning | Intermittent positive-pressure breathing (IPPB) |
| Mobilization/rehabilitation | Continuous positive airways pressure (CPAP) |
| Non-invasive ventilation (NIV) | |
| Nasopharyngeal/oral suction | |
| Positive expiratory pressure (PEP) mask, flutter valve | |
| Mobilization/rehabilitation |
MANUAL HYPERINFLATION
In this technique a self-inflating circuit is used to deliver a volume of gas 50% greater than tidal volume (VT) via an endotracheal or tracheostomy tube. An augmented VT may recruit atelectatic lung secondary to reduced airflow resistance and enhanced interdependence via the collateral channels of ventilation.3 Bronchial secretions may be mobilised by the increased expiratory flow rate and/or stimulation of a cough.4 However, ventilator hyperinflation, the delivery of an augmented VT via the ventilator, has been shown to be as effective in the removal of secretions and maintenance of static lung compliance as conventional manual hyperinflation (MHI).5 This may also avoid cardiopulmonary instability associated with ventilator disconnection and loss of positive end-expiratory pressure (PEEP). In an emergency situation an Ambu-bag and facemask can be used to perform MHI in the self-ventilating patient. However, an alternative technique such as intermittent postitive-pressure breathing (IPPB) should be considered when an augmented VT is required during a therapeutic intervention (Table 5.2).
Table 5.2 Potential advantages and complications of manual hyperinflation
| Potential advantages |
| Reversal of acute lobar atelectasis3 |
| Alveolar recruitment via channels of collateral ventilation3 |
| Improvement in arterial oxygenation |
| Mobilisation of secretions and contents of aspiration5 |
| Improved static lung compliance5 |
| Effectiveness may be increased when combined with appropriate positioning and manual techniques1 |
| Potential complications |
| Absolute contraindications include undrained pneumothorax and unexplained haemoptysis |
| Cardiovascular and haemodynamic instability6 |
| Loss of PEEP, inducing hypoxia and potential lung damage. This can be minimised by incorporating a PEEP valve into the circuit of a ‘PEEP-dependent’ patient |
| Risk of volutrauma, barotrauma and pneumothorax,7 which can be reduced by including a manometer in the circuit |
| Risk of increased intracranial pressure |
| Increased patient stress and anxiety |
PEEP, positive end-expiratory pressure.
RECRUITMENT MANOEUVRES
Recruitment manoeuvres may be employed to reverse hypoxaemia in patients with acute lung injury (ALI)/acute respiratory distress syndrome (ARDS). A recruitment manoeuvre involves a transient increase in transpulmonary pressure in an attempt to reinflate and maintain atelectatic lung units.8 No standard approach exists; however, common options include: the application of incremental levels of continuous positive airways pressure (CPAP) with no tidal excursion; incremental increases in PEEP with additional VT; and the application of intermittent larger ‘sigh’ breaths. In randomised studies, although recruitment manoeuvres may transiently improve oxygenation, there is as yet no proven outcome benefit.9
SUCTION
Suction is used to clear secretions from central airways when a cough reflex is impaired or absent. A suction catheter is passed via an endotracheal or tracheostomy tube or via a nasal/oral airway to the carina, and this may stimulate a cough in a non-paralysed patient (Table 5.3). The catheter is pulled back 1 cm before suction is applied on withdrawal. The suction catheter diameter should not be greater than 50% of the diameter of the airway through which it is inserted as large negative pressure can be generated intrathoracically without air entrainment. The use of suction following effective MHI optimises removal of secretions.10 Instillation of normal saline prior to suctioning remains controversial; however, it may stimulate a cough, maximising secretion mobilisation and clearance.
Table 5.3 Potential advantages and complications of suction
| Potential advantages |
| Stimulation of a cough when reflex is impaired by mechanical stimulation of the larynx, trachea or large bronchi |
| Removal of secretions from central airways when cough is ineffective or absent |
| Potential complications |
| Tracheal suction is an invasive procedure and should only be undertaken when there is a clear indication |
| Absolute contraindications to suctioning are unexplained haemoptysis, severe coagulopathies, severe bronchospasm, laryngeal stridor, base-of-skull fracture and a compromised cardiovascular system |
| Hypoxaemia can be induced secondary to suctioning. This can be limited by pre- and postoxygenation |
| Cardiac arrhythmias may be more common in the presence of hypoxia |
| Tracheal stimulation may produce increased sympathetic nervous system activity or a vasovagal reflex producing cardiac arrhythmias and hypotension |
MANUAL TECHNIQUES
CHEST SHAKING AND VIBRATIONS
Shaking and vibrations are oscillatory movements of large and small amplitude performed during expiration, and are thought to increase expiratory flow rate, aiding mucociliary clearance.11 These techniques are believed to be more effective when performed at high lung volumes.
CHEST WALL COMPRESSION
Compression of the chest wall can be used to augment an expiratory manoeuvre such as a ‘huff’ (see section on active cycle of breathing technique (ACBT), below) or a cough by providing tactile stimulation, or wound support.
NEUROPHYSIOLOGICAL FACILITATION (NPF) OF RESPIRATION
NPF of respiration is a set of techniques designed for the treatment of the neurologically impaired adult. Manual externally applied stimuli to the thorax, abdomen and mouth can be used to stimulate increased VT, a cough reflex, augmented contraction of the abdominal muscles or an increased conscious level.12,13
POSITIONING
A simple change of position can have a profound effect on cardiopulmonary physiology14,15 (Table 5.4). As such, positioning is commonly utilised to achieve several different goals: drainage of secretions using gravity-assisted positioning (GAP), reduction of the work of breathing/breathlessness or to optimise V/Q matching.
Table 5.4 Potential advantages and complications of mobilisation14
| Potential advantages | |
|---|---|
| Positioning supine to upright | Mobilisation |
| ↑ Lung volumes | ↑ Ventilation |
| ↑ Lung compliance | ↑ V/Q matching |
| ↓ Airway closure | ↑ Recruitment of lung units |
| ↑ PaO2 | ↑ Surfactant production/distribution |
| ↓ Work of breathing | ↑ Mobilisation of secretions |
| ↑ Mobilisation of secretions | ↑ Cardiopulmonary fitness and exercise capacity |
| Potential complications | |
| Cardiovascular/neurological/haematological instability | |
| Increased oxygen/ventilatory requirement | |
(Adapted from Dean E: The effects of positioning and mobilization on oxygen transport. In: Pryor JA, Webber BA (eds) Physiotherapy for Respiratory and Cardiac Problems, 2nd edn. Edinburgh: Churchill Livingstone; 1998: 125.)
GRAVITY-ASSISTED POSITIONING
GAP facilitates the removal of excess bronchial secretions by positioning a specific bronchopulmonary segment perpendicular to gravity (Table 5.5). This technique is not used in isolation but in conjunction with augmented VT, via the ventilator, MHI or ACBT in a spontaneously breathing patient. An individual position exists for each bronchopulmonary segment based on the anatomy of the bronchial tree;16 however, these may need modification in the ICU setting.
Table 5.5 Potential advantages and complications of gravity-assisted positioning (GAP)
| Potential advantages |
| Maximises removal of excess bronchial secretions when combined with active cycle of breathing technique |
| Allows accurate treatment of specific bronchopulmonary segments |
| Self-treatment can be included in a home programme on discharge |
| Potential complications |
| Positions need modification when used in the presence of cardiovascular/neurological instability, haemoptysis or gastric reflux |
REDUCTION OF THE WORK OF BREATHING
A reduction in the work of breathing/breathlessness can be achieved by putting a patient in a position that optimises the length–tension relationship of the diaphragm, promotes relaxation of the shoulder girdle and upper chest and facilitates the use of breathing control.17 This approach to positioning is particularly effective when used in conjunction with non-invasive ventilation (NIV). Adequately supported high side-lying is a useful position to promote relaxation of the breathless patient. In addition, it can discourage the overuse of accessory muscles of respiration, which may reduce energy expenditure. Some patients prefer forward lean-sitting with their arms placed in front of them on a high table. In this position the length–tension relationship of the diaphragm is optimised secondary to forward displacement of the abdominal contents.
VENTILATION/PERFUSION
Appropriate positioning of a patient can maximise V/Q.18 In the self-ventilating adult, V/Q matching increases from non-dependent to dependent areas of lung.19 However, in adults receiving positive-pressure ventilation lung mechanics are altered, producing V/Q inequality. In this situation non-dependent areas of lung are preferentially ventilated while dependent regions are optimally perfused; as such, a regular change of position is recommended.
In an extreme form prone positioning has been used to improve refractory hypoxaemia in patients with ALI/ARDS. The mechanisms behind these improvements are complex, but likely centre around a combination of a redistribution of some pulmonary perfusion together with a more homogeneous distribution of ventilation, leading to improved V/Q matching. Although prone positioning improves oxygenation in 70% of patients with ALI/ARDS, its role in improving outcome remains controversial.20
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