Non-invasive ventilation


The British Thoracic Society (BTS) published guidelines in 2002 on the use of non-invasive ventilation in acute respiratory failure. Following these the Royal College of Physicians published guidelines in 2008.

Recommended initial settings for bi-level pressure support in COPD
  • Expiratory Positive Airway Pressure (EPAP): 4-5 cm H2O
  • Inspiratory Positive Airway Pressure (IPAP): RCP advocate 10 cm H20 whilst BTS suggest 12-15 cm H2O
  • back up rate: 15 breaths/min
  • back up inspiration:expiration ratio: 1:3


Non-invasive ventilation - key indications
  • COPD with respiratory acidosis pH 7.25-7.35*
  • type II respiratory failure secondary to chest wall deformity, neuromuscular disease or obstructive sleep apnoea
  • cardiogenic pulmonary oedema unresponsive to CPAP
  • weaning from tracheal intubation

*the BTS guidelines state that NIV can be used in patients who are more acidotic (i.e. pH < 7.25) but that a greater degree of monitoring is required (e.g. HDU) and a lower threshold for intubation and ventilation should be used