4 Lung Mechanics and Ventilation - Clinical Applications Flashcards
What is interstitial lung disease?
Disorder characterised by ‘stiffer lungs’
Group of diseases
Diffuse lung/pulmonary fibrosis
(Cause example: Inorganic dusts- asbestos)
(Airways not narrowed like in emphysema)
What is the ‘interstitial space’ in the lungs?
Potential space between alveolar cells and capillary basement membrane
Only in disease states
(May contain fibrous tissue, cells or fluid)
What effects does the deposition of fibrous tissue in the interstitium have?
- Lungs= stiffer, harder to expand
- reduced Lung Compliance
- Elastic recoil of lungs= increased
- Lungs shrunken
- Thickened alveolar walls- increased diffusion distance
What are the signs and symtoms of interstitial lung disease?
SIGNS:
chest expansion reduced (bilaterally)
inspiratory capacity and vital capacity (spirometry) = reduced
tachypnoea
tachycardia
Coarse crackles
SYMPTOMS:
Shortness of breath
reduced exercise tolerance
dry cough
Give an example of a cause of interstitial lung fibrosis
What are the signs of respiratory distress syndrome?
cyanosis
grunting
intercostal and subcostal recession
Respiratory distress syndrome is caused by a deficiency in surfactant production in (premature) new borns <30weeks. What effects does this have?
Surface tension= high
Reduced compliance
Lung expansion incomplete
Increased effort required to breathe
How is respiratory distress syndrome treated?
Surfactant replacement via endotracheal tube
Supportive treatment:
- Oxygen
- Assisted ventilation
What is emphysema?
Irreversible loss of elastin and breakdown of alveolar walls- causing increased lung compliance and narrowing of small airways
(feature of COPD)
Explain the effects of the loss of elastin fibres:
- Lungs easier to expand
- Increased lung compliancw
- Reduced elastic recoil of lungs
- Lungs= hyperinflated at rest (Barrel chest)
- Small airways narrowed
- Loss of radial traction on small bronchioles
SYMPTOMS
Shortness of breath
Reduced exercise tolerance
Apart from smoking, what is another cause of emphysema?
Alpha-1 antitrypsin deficiency (INHERITED)
Imbalance in proteinases and antiproteinases
Early age:
Destruction of elastin
What is asthma? Describe its effects in the lungs.
Reversible airway obstruction
Chronic inflammatory process
May be triggered by allergic stimuli
Effects:
- Airway narrowing
- Bronchial smooth muscle contraction
- Thickening of airway walls by muscosal oedema
- Excess mucus production (partially block lumen)
What is a pneumothorax?
Disorder- air enters pleural space
Loss of pleural seal and lung collapse
(Lung pulled in towards hilum)
What is atelectasis?
Lung collapse
Incomplete expansion of lungs (neonatal)
Collapse of previously inflated lung
—> producing areas of airless pulmonary tissue
What are the 2 main types of atelectasis?
-
Compression atelectasis
- Siginificant volume of air or fluid in pleural cavity
- Pneumothorax
- Pleural efusion
- Siginificant volume of air or fluid in pleural cavity
-
Resorption atelectasis
- complete obstruction of an airway
- eventually air reabsorbed from alveoli which collapse
- eg due to bronchial carcinoma
Where should a tube be inserted to release the air from a pneumothorax to avoid damage to blood vessels?
Just above rib
