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Practice Therapeutics

Emergency oxygen use

BMJ 2012; 345 doi: (Published 18 October 2012) Cite this as: BMJ 2012;345:e6856
  1. Ronan O’Driscoll, consultant respiratory physician
  1. 1Manchester Academic Health Sciences Centre, University of Manchester, Salford Royal University Hospital, Respiratory Medicine, Salford, UK
  1. ronan.o’driscoll{at}
  • Accepted 20 September 2012

A 60 year old man with chronic obstructive pulmonary disease (COPD) requiring long term home oxygen therapy called an ambulance because of severe breathlessness. With nasal oxygen therapy at 2 L/minute, his oxygen saturation was 88%. The paramedics administered nebulised salbutamol driven by oxygen (approximately 60% oxygen) and then gave oxygen via a reservoir mask (approximately 80% oxygen) during a 27 minute journey to hospital. He became drowsy before arrival in the emergency department, and blood gases showed evidence of respiratory acidosis with pH 7.19 (normal range 7.35-7.45), elevated CO2 level at 11.3 kPa (normal range 4.5-6.0), elevated bicarbonate level at 32 mmol/L (normal range 21.0-28.0), and high oxygen partial pressure at PaO2 18.5 kPa (normal range 12.0-15.0) with high oxygen saturation at 100% (normal range 95-98%). He required intubation and ventilation for acidotic hypercapnic respiratory failure, but he died on the second day of ventilation.

Emergency oxygen use

Oxygen is administered to about a third of emergency ambulance patients, and about 15% of UK hospital patients receive oxygen therapy on any given day.1 2 Common indications for emergency oxygen therapy are shown in box 1, while box 2 shows some common conditions for which oxygen was given routinely in the past but is now recommended only if the patient is hypoxaemic. Patients with carbon monoxide or cyanide poisoning and patients with some diving or altitude emergencies benefit from hyperoxaemia, but the prevention of hypoxaemia is the goal of oxygen therapy in all other conditions. Several publications have raised concerns about the risks of either insufficient or excessive oxygen therapy.3 4 5 6 7 8 9

Box 1: Medical emergencies where oxygen is likely to be required until patient is stable and within target saturation range3

Medical emergencies requiring high concentration oxygen in all cases
  • Shock, sepsis, major trauma

  • Cardiac arrest and during resuscitation

  • Anaphylaxis

  • Carbon monoxide or cyanide poisoning

Medical emergencies where patients are likely to need oxygen therapy (ranging from low to high concentration depending on disease severity), with target saturation range 94-98%
  • Pneumonia

  • Asthma

  • Acute heart failure

  • Pulmonary embolism

Medical emergencies where patients are likely to need controlled oxygen, with target saturation range 88-92%
  • Acute exacerbation of chronic obstructive pulmonary disease (COPD)

  • Acute illness in …

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