CPAP definition etc

• Continuous Positive Airway Pressure (CPAP):

  • Provides Positive End Expiratory Pressure (PEEP)
  • Provides positive pressure throughout inspiration and expiration
  • It is used to provide respiratory support to the patient – it isn’t a physiotherapy treatment adjunct

  
• The physiological effects of PEEP:

  • increase in Functional residual capacity – made up of expiratory reserve volume (air that can be expired with maximal effort after end of quiet inspiration) and residual volume (air left in lungs)
  • Recruit alveoli
  • increase in surface area for gas exchange
  • Decrease in work of breath (compliance curve)
  • Improve oxygenation

  
• Indications for CPAP:

  • Type 1 Respiratory Failure - hypoxemia with normal level of co2
  • Possible conditions
  • Covid pneumonia
  • Pneumonia
  • Pulmonary oedema
  • Bibasal atelectasis post-op (collapse of both lower lung lobes due to decrease in functional residual capacity)
• Application of CPAP:

  • 5 cmH2O PEEP lowest setting
  • 7.5 cmH2O usual adult setting
  • 10 cmH2O for large adult/severe hypoxaemia
  • Titrate FiO2 using SaO2
  • Nasal bridge pressure care
  • Often poorly tolerated