Respiratory failure Flashcards
What is respiratory failure?
Not a presentation seen in isolation but a possible outcome of various respiratory diseases
Either the failure of oxygenation of the blood or a failure to remove carbon dioxide from the blood (or both)
What are the types of respiratory failure?
Type 1 = acute hypoxemia - hypoxia but normocapnia
PaO2 = <8kPa
Type 2 = hypoxia and hypercapnia
PaO2 <8kPa and PaCO2 >6kPa
Discuss type 2 respiratory failure
Hypoxia + hypercapnia
AKA ventilatory failure
Occurs when alveolar ventilation is insufficient to remove CO2
Most common cause is COPD
Other causes: chest wall deformities, resp. muscle weakness and depression of resp centre (drug overdose)
Why should caution be exercised when prescribing oxygen for patients with COPD?
Patients often have type 2 respiratory failure and have become insensitive to hypercapnia (usually drives breathing) therefore they rely on hypoxemia to drive respiration
Giving oxygen removes their respiratory drive and further increases PaCO2
What is the most sensitive clinical indicator of increasing respiratory difficulty?
Increasing respiratory rate
Discuss blood gas analysis
- Analyse sample immediately - if not metabolism occurs and PO2 will decrease and PCO2 will rise
- Get rid of air bubbles in sample
What is capnography?
Continuous breath by breath analysis of expired CO2
How are patients with respiratory failure managed?
- Administration of supplemental oxygen
- Treatment for any airway obstruction
- Measures to limit pulmonary oedema
- Control of secretions
- Treatment of infection
What are the benefits of mechanical ventilation?
Relief from exhaustion
Prevent or reverse atelectasis (collapse or closure of a lung due to absence of gas exchange)
Improved carbon dioxide clearance
