British Thoracic Society Guideline for oxygen use in adults in healthcare and emergency settings

EXECUTIVE SUMMARY Philosophy of the guideline ✓ Oxygen is a treatment for hypoxaemia, not breathlessness. Oxygen has not been proven to have any consistent effect on the sensation of breathlessness in nonhypoxaemic patients. ✓ The essence of this guideline can be summarised simply as a requirement for oxygen to be prescribed according to a target saturation range and for those who administer oxygen therapy to monitor the patient and keep within the target saturation range. ✓ The guideline recommends aiming to achieve normal or near-normal oxygen saturation for all acutely ill patients apart from those at risk of hypercapnic respiratory failure or those receiving terminal palliative care. 1. Assessing patients ○ For critically ill patients, high concentration oxygen should be administered immediately (table 1 and figure 1) and this should be recorded afterwards in the patient’s health record. ○ Clinicians must bear in mind that supplemental oxygen is given to improve oxygenation, but it does not treat the underlying causes of hypoxaemia which must be diagnosed and treated as a matter of urgency. ○ The oxygen saturation should be checked by pulse oximetry in all breathless and acutely ill patients, ‘the fifth vital sign’ (supplemented by blood gases when necessary), and the inspired oxygen concentration should be recorded on the observation chart with the oximetry result. (The other vital signs are pulse rate, blood pressure, temperature and respiratory rate). ○ Pulse oximetry must be available in all locations where emergency oxygen is used. Clinical assessment is recommended if the saturation falls by ≥3% or below the target range for the patient. ○ All critically ill patients outside of a critical care area (e.g. intensive care unit (ICU), high dependency unit (HDU), respiratory HDU), should be assessed and monitored using a recognised physiological track and trigger system such as the National Early Warning Score (NEWS). 2. Target Oxygen prescription ○ Oxygen should be prescribed to achieve a target saturation of 94–98% for most acutely ill patients or 88–92% or patient-specific target range for those at risk of hypercapnic respiratory failure (tables 1–4). ○ Best practice is to prescribe a target range for all hospital patients at the time of admission so that appropriate oxygen therapy can be started in the event of unexpected clinical deterioration with hypoxaemia and also to ensure that the oximetry section of the early warning score (EWS) can be scored appropriately. ○ The target saturation should be written (or ringed) on the drug chart or entered in an electronic prescribing system (guidance on figure 1). 3. Oxygen administration ○ Oxygen should be administered by staff who are trained in oxygen administration.