o Causes of atelectasis
o Lack of distending forces on lung
Weak diaphragm
Reduced lung volume
(less negative pleural pressure)
CNS dysfunction
Weak resp mms
o Localised airway obstruction
Sputum
Small airway collapse
Absorption of gas occurs and alveoli collapses
o Insufficient surfactant
Prematurity
Lack of lung stretch (sigh)
Anesthesia
High FiO2
Persistent collapse
o Negative airway pressure
Suctioning
o ↑ Lung elastic recoil
Decreased compliance
Low lung volumes
Interstitial fibrosis
o
Most patients have degree of atelectasis post-surgery, clinical course varies but mild cases are self-limiting. Significant if:
Results in respiratory dysfunction/compromise
Has potential to become more serious respiratory pathology
Outline the assessment of alveolar ventilation and lung volume.
o Subjective examination (SOB, difficulty breathing, unable to clear secretions).
o Investigations (CXR, ABGs, pulmonary function tests [PFT] e.g. FVC, FEV1).
o Observation (↑ RR, shallow breathing, ↓ chest expansion).
o Palpation (poor LBE/local chest expansion).
o Listen (auscultation- reduced, absent, BBS, crackles, weak/ineffective cough).
Describe (in terms of physiological background, practical performance, evidence of effectiveness, precautions and contraindications), the physiotherapy techniques which can be used to treat disorders of alveolar ventilation and lung volume.
o Rx for ↓ ventilation aimed at improving lung volume and optimising ventilation/perfusion matching.
o Can be global (↓ PaO2 ↑ PaCO2) or regional (↓ PaO2, ↑ PaCO2 if large area).
Breathing exercises o Aims to:
↑inhaled volume and promote expansion of alveoli by interdependence and collateral ventilation.
↑ Tidal volume (to increase alveolar ventilation and stretch- preventing/reversing atelectasis).
o Can add sustained maximal inhalation or inspiratory hold.
o Needs to be:
Slow
More contribution from abdominal/diaphragmatic component rather than costal / rib cage.
Ventilation may be preferentially distributed to the dependent lung.
Deeper than tidal volume
Increased lung volume, better lung compliance.
Hand position on lateral chest wall to encourage correct pattern of breathing – diaphragm/abdominal.
Sustained inspiration or inspiratory hold
time for "slow" alveoli to open
Collateral ventilation / interdependence
Don’t encourage contraction of abdo mms or closing of glottis.
o Contraindications/precautions:
Hyperinflation
Undrained pneumothorax
Respiratory distress
o Indications:
↓ Alveolar ventilation (from reversible pathology- global or regional).
↓ Lung volumes from reversible pathology.
E.g. post-op patient, lung collapse/consolidation, post- effusion drainage.
o Hand position on thorax o Relaxed shoulders
o Concentrating on slow LBE
o Improved pattern of breathing – not encouraging increased volume at all costs
o Evidence for effectiveness is physiology based- very little research evaluating breathing exercises as used by physiotherapists.
o Should be combined with appropriate positioning.
