Respiratory Failure Flashcards
What causes insufficient ventilation?
Obstruction of airways or failure to breathe adequately
What causes insufficient gas exchange?
Exchange surface dysfunction or VQ mismatch
What are the four causes of hypoxaemia?
- Insufficient ventilation
- Insufficient gas exchange
- Insufficient oxygen-carrying capacity
- Insufficient oxygen in the atmosphere
What is the cause of type 1 respiratory failure?
Decreased oxygenation
What is the cause of type 2 respiratory failure?
Decreased ventilation
What are the effects of type 1 respiratory failure?
- Decreased alveolar partial pressure of O2
- Normal arterial partial pressure of O2
- Normal PaCO2
- Normal pH
What are the effects of type 2 respiratory failure?
- Decreased alveolar partial pressure of O2
- Decreased arterial partial pressure of O2
- Increased PaCO2
- Decreased pH
What are the two types of hypoventilation?
Airway obstruction due to physical blockage or problems with initiation or mechanics of breathing
Give examples of airway obstruction hypoventilation
- Asphyxia
- Smooth muscle constriction
- Obstructive sleep apnoea
- Bronchial obstruction (asthma, chronic bronchitis, cystic fibrosis)
What causes the other type of hypoventilation (initiation)?
- Drug (opioid) overdose
- Stroke
- Neuromuscular disease (muscular dystrophy, motor neurone disease)
- Issues with lung mechanics (COPD, pulmonary fibrosis, NRDS, pneumothorax)
What causes oxygenation problems?
V/Q mismatch
What is the dead space effect?
Reduced perfusion of lung regions therefore increases V/Q ratio
What are the effects of the dead space effect?
Heart failure, blocked vessels and loss /damage of capillaries
What is the shunt effect?
Reduced ventilation or limited diffusion, causing a decrease in V/Q ratio
Give some diseases where the shunt effect happens
- Pneumonia
- Atelectasis (Collapsed lung)
