Table 2 Serious illnesses requiring moderate levels of supplemental oxygen if the patient is hypoxaemic (section 8.11)
  • The initial oxygen therapy is nasal cannulae at 2–6 l/min (preferably) or simple face mask at 5–10 l/min unless stated otherwise.

  • For patients not at risk of hypercapnic respiratory failure who have saturation <85%, treatment should be commenced with a reservoir mask at 10–15 l/min.

  • The recommended initial oxygen saturation target range is 94–98%.

  • If oximetry is not available, give oxygen as above until oximetry or blood gas results are available.

  • Change to reservoir mask if the desired saturation range cannot be maintained with nasal cannulae or simple face mask (and ensure that the patient is assessed by senior medical staff).

  • If these patients have co-existing COPD or other risk factors for hypercapnic respiratory failure, aim at a saturation of 88–92% pending blood gas results but adjust to 94–98% if the Paco2 is normal (unless there is a history of previous hypercapnic respiratory failure requiring NIV or IPPV) and recheck blood gases after 30–60 min.

Additional commentsGrade of recommendation
Acute hypoxaemia (cause not yet diagnosed)Reservoir mask at 10–15 l/min if initial Spo2 <85%, otherwise nasal cannulae or simple face maskGrade D
Patients requiring reservoir mask therapy need urgent clinical assessment by senior staff
Acute asthmaGrade C
PneumoniaGrade C
Lung cancerGrade C
Postoperative breathlessnessManagement depends on underlying causeGrade D
Acute heart failureConsider CPAP or NIV in cases of pulmonary oedemaGrade D
Pulmonary embolismMost patients with minor pulmonary embolism are not hypoxaemic and do not require oxygen therapyGrade D
Pleural effusionsMost patients with pleural effusions are not hypoxaemic. If hypoxaemic, treat by draining the effusion as well as giving oxygen therapyGrade D
PneumothoraxNeeds aspiration or drainage if the patient is hypoxaemic. Most patients with pneumothorax are not hypoxaemic and do not require oxygen therapyGrades C and D
Use a reservoir mask at 10–15 l/min if admitted for observation. Aim at 100% saturation (oxygen accelerates clearance of pneumothorax if drainage is not required)
Deterioration of lung fibrosis or other interstitial lung diseaseReservoir mask at 10–15 l/min if initial Spo2 <85%, otherwise nasal cannulae or simple face maskGrade D
Severe anaemiaThe main issue is to correct the anaemiaGrades B and D
Most anaemic patients do not require oxygen therapy
Sickle cell crisisRequires oxygen only if hypoxaemic (below the above target ranges or below what is known to be normal for the individual patient)Grade B
Low oxygen tension will aggravate sickling
  • COPD, chronic obstructive pulmonary disease; CPAP, continuous positive airway pressure; IPPV, intermittent positive pressure ventilation; NIV, non-invasive ventilation; Paco2, arterial carbon dioxide tension; Spo2, arterial oxygen saturation measured by pulse oximetry.