Session 1- Clinical Application in Ventilation and Lung Mechanics Flashcards
Atelactasis
Complete or partial lung collapse
Impaired pulmonary surfactant production
Interstitial lung disease
Lung expansion difficult secondary to stiff lungs from increased collagen in alveolar walls – decreased compliance/increased elastic recoil
hypoventilation
Inability to expand chest and ventilate
Pneumothorax
Air in the intrapleural space with loss of pleural seal
Obstructive lung disease- COPD and asthma
Increase in airways resistance and, in emphysema decreased elastance/elastic recoil secondary to loss elastic fibres – compliance increased but elastic recoil decreased
Respiratory distress syndrome new born
Decrease in surfactant leads to increased surface tension and decreased compliance
What is COPD
Clinical syndrome characterised by chronic respiratory symptoms with associated pulmonary abnormalities- all conditions share impaired airflow that is not fully reversible
- chronic bronchitis
- emphysema
Chronic bronchitis
A disease of the small airways- inflammation in the smaller bronchi and bronchioles- airways chronically inflamed
– Increased air flow resistance– worse on expiration
– Alteration of airway surface tension(increased) predisposing to small airway
collapse - worse on expiration
Pathology of chronic bronchitis
- Mucous hypersecretion
- Reduced cilia and impaired function – mucous is not cleared effectively - narrows airways
- Epithelial remodelling - also narrows airways
- Loss of small airways
- Increased airway surface tension - fewer clara cells (less surfactant-like material in airways)
What is COPD emphysema
Abnormal permanent enlargement of the air spaces distal to the terminal bronchiole with destruction of alveolar walls
Inflammatory cells accumulate
-release elastases and oxidants which destroy alveolar walls
Reduced elastic recoil
- harder to exhale
- small airways collapse
Difference between structure of bronchus and bronchiole
Bronchus has small islands of cartilage and glands in submucosa
Bronchiole has no cartilage or glands
How do bronchioles stay open
Radial traction
What is radial traction
Outward tugging action Prevents collapse of bronchioles during expiration
What is Barrel chest
Increased air flattens diaphragm- cant contract as effectively- impaired inspiration
Airway obstruction in COPD
Small airways narrowed through thickened bronchioles periphery wall causes by inflammation and field narrowing asa result of fibrosis
Luminal occlusion by mucus and inflammatory exudate
Compression alectasis aetiology
Pressure on alveoli
- air in pleural cavity
- Fluid in pleural cavity
- abdominal obesity
- GI surgery post-opp distension pushing up and compressing alveoli
Resorption collapse
is a form of lung collapse that is due to obstruction of the airways supplying a lung segment or lobe
Alveoli collapse
What is contained within the interstitium between the alveolus and capillary
Elastin fibres
Collagen
Fibroblasts
Matrix substance
BASEMENT MEMBRANE
What is the state of the pulmonary interstitium in pulmonary fibrosis
Thickened which increases diffusion distance for 02 and c02
Impairs gas exchanges
Interstitial lung disease lung mechanics
Lung compliance is reduced- lungs re stiff and harder to expand
Elastic recoil of the lungs is increased - he resting lung volume is smaller than normal
Restrictive type of ventilators defect
Interstitial lung disease symptoms
– Dry cough
– Dyspnoea on exertion progressing
to at rest
– Fatigue
Signs of interstitial lung disease
- decreased lung excursion on palpation
- bi-basal end inspiratory lung crackles
-Finger clubbing - Small pleural effusions
In diffuse pulmonary fibrosis will functional residual capacity be reduced or increased
Decreased
Functional residual capacity
Volume of air in the lungs at the end of quiet expiration
What produces surfactant
Type 2 pneumocytes
When is the amount of surfactant surffienct
35-36 weeks
Neonatal respiratory distress syndrome
Lac of surfactant in pre term babies
Lung expansion is incomplete
Some alveoli remain collapsed
Lung is stiff
Increased effort is required to breathe
Neonatal respiratory distress syndrome signs
Ø Grunting, Ø Nasal flaring, Ø Intercostal and subcostal retractions Ø Rapid respiratory rate (tachypnoea) Ø Cyanosis
In COPD emphysema will FRC at the end of quiet expiration be reduced or increased
Increased
Increased compliance due to low of elastic tissue which means decreased elastic recoil
Problem with airflow in emphysematous dominant COPD
- loss of elastic tissue
- increased compliance and reduced elastic recoil
- hyper inflated
- small airways collapse in expiration
- air trapping
- increased FRC
Problem with airflow in pulmonary fibrosis
- increase of fibrous tissue
- less compliant
- smaller lungs
- decreased FRC
- no airway obstruction
What would h happen if the pleural seal was broken
Collapse
What happen s in pneumothorax
• Chest wall or the lung is breached - tear in parietal or visceral pleura • A communication is created between pleural space and atmosphere • Air flows from atmosphere (higher pressure) à into the pleural cavity (lower pressure) • Until the pleural pressure = atmospheric pressure • The pleural seal is lost • Lung elastic recoil not counter-balanced by negative pleural pressure/chest wall • Lung collapses to unstretched size `
What is hypoventilation
Failure to breathe rapidly enough or deeply enough
