4 Lung Mechanics and Ventilation - Clinical Applications Flashcards Preview

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Flashcards in 4 Lung Mechanics and Ventilation - Clinical Applications Deck (19)
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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?


chest expansion reduced (bilaterally)

inspiratory capacity and vital capacity (spirometry) = reduced



Coarse crackles


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?



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


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


  • 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
  • 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


How are inhaled particles and dust removed from the respiratory tract?

Mucocilliary escalator

Mucus traps dust 

Cilia move it along--> swallowedf

Macrophages ingest small particles


Why is physiological dead space increased by a pulmonary embolism?

No gas exchange occuring in alveoli

Since Physiological dead space= alveolar dead space + anatomical dead space

--> physiological dead space increased as alveolar dead space has been increased


What will be the effect on resistance if there is inhalation of a B2 adrenoreceptor agonist?

Bronchodilation and reduction in resistance