Oxygen therapy is the administration of oxygen as a medical intervention, which can be for a variety of purposes in both chronic and acute patient care. Oxygen is essential for cell metabolism, and in turn, tissue oxygenation is essential for all normal physiological functions.
High blood and tissue levels of oxygen can be helpful or damaging, depending on circumstances and oxygen therapy should be used to benefit the patient by increasing the supply of oxygen to the lungs and thereby increasing the availability of oxygen to the body tissues, especially when the patient is suffering from hypoxia and/or hypoxaemia.
Indications for use
Oxygen is used as a medical treatment in both chronic and acute cases, and can be used in hospital, pre-hospital or entirely out of hospital, dependant on the needs of the patient and the views of the medical professional advising.
Use in chronic conditions
A common use of supplementary oxygen is in patients with chronic obstructive pulmonary disease (COPD),the occurrence of chronic bronchitis or emphysema, a common long term effect of smoking, who may require additional oxygen to breathe either during a temporary worsening of their condition, or throughout the day and night. It is indicated in COPD patients with PaO2 ≤ 55mmHg or SaO2 ≤ 88% and has been shown to increase lifespan.Oxygen is often prescribed for people with breathlessness, in the setting of end-stage cardiac or respiratory failure, advanced cancer or neurodegenerative disease, despite having relatively normal blood oxygen levels. A 2010 trial of 239 subjects found no significant difference in reducing breathlessness between oxygen and air delivered in the same way
Use in acute conditions
Oxygen is widely used in emergency medicine, both in hospital and by emergency medical services or advanced first aiders.In the pre-hospital environment, high flow oxygen is definitively indicated for use in resuscitation, major trauma, anaphylaxis, major haemorrhage, shock, active convulsions and hypothermia.
It may also be indicated for any other patient where their injury or illness has caused hypoxaemia, although in this case oxygen flow should be moderated to achieve target oxygen saturation levels, based on pulse oximetry (with a target level of 94–98% in most patients, or 88–92% in COPD patients).
For personal use, high concentration oxygen is used as home therapy to abort cluster headache attacks, due to its vaso-constrictive effects.