Reduced lung volumes - Lecture 1 Flashcards
Causes of reduced lung volumes:
Interruption to mechanics of ventilation
Increased resistance to flow of air into lungs
Altered control of ventilation
Clinical significance of reduced total lung volume & vital capacity:
Pt cannot sufficiently expand lung tissue
Airway clearance impairment
Reduced exercise tolerance
Increased risk to secondary infections
Clinical significance of reduced functional residual capacity:
May not be able to sustain alveolar ventilation
Impairment of gas exchange
Dyspnoea
Impairments that contribute to reduced LV:
Pain Impaired airway clearance Respiratory muscle dysfunction Musculoskeletal dysfunction Airflow limitation
Functional residual capacity:
Residual volume + expiratory reserve volume
The volume at which there is an equilibrium between the outward elastic recoil of the chest wall, and the inward elastic recoil of the lungs
Closing volume definition:
volume of air in lungs at which alveoli closure first occurs
Closing capacity =
Closing volume + residual volume
Factors that increase FRC
Aging
Emphysema
Obstructive lung disease
erect body position
Factors that decrease FRC
Body position Anaesthesia/muscle relaxants reduced muscle tone Abdominal distention/pregnancy restrictive lung disease pulmonary oedema obesity abdominal surgery
Atelectasis definition:
inadequate alveolar ventilation of varying degrees
Atelectasis types
Resorption - air diffuses across into blood
Compression - air squeezed out by force
Contraction - tissue strength not enough to keep alveoli open
Acute conditionscommonlyinfluencinglungvolumes
• # ribs, chest trauma • Pneumonia • Post‐operatively (esp. UAS, cardiac, thoracic) • Pleural effusion, emphysema, pneumothorax • Pregnancy
Chronic conditionscommonlyinfluencinglungvolumes
- Pulmonary fibrosis
- Kyphoscoliosis
- Stroke, brain tumour
- Spinal cord injury
- Obesity
- Resp muscle weakness
Clinical features of reduced lung volume: LOOK
‐ apical breathing pattern ‐ rapid, shallow breathing ‐ reduced expansion of the chest wall ‐ distended abdomen ‐ postural abnormalities – kyphosis/scoliosis/kyphoscoliosis
Clinical features of reduced lung volume: LISTEN
‐ auscultation – absent, reduced or bronchial breath sounds
‐ cough – weak due to inadequate inspiration
