Sepsis Six: oxygen first for hypoxaemia
In adults, the Sepsis Six is a bundle of actions delivered together within one hour of recognising sepsis; oxygen is the first element, given to correct hypoxaemia (low blood oxygen).
Remember
Oxygen is the first element of the Sepsis Six and is given early, because only oxygen directly corrects hypoxaemia.
Memory aid
three to give (oxygen, antibiotics, fluids) and three to check (cultures, lactate, urine output)
Remember the six as three treatments to give and three checks, with oxygen the first of the treatments.
In adults, the Sepsis Six is a bundle (a fixed set of actions delivered together) made up of three treatments and three checks. The treatments are oxygen, intravenous antibiotics and intravenous fluids. The checks are blood cultures (blood samples sent to the laboratory to grow any bacteria), a lactate level and hourly urine output. All six are to be completed within one hour of recognising sepsis.
In a patient who is hypoxaemic (low blood oxygen), oxygen is listed first because it treats the problem that is already present. In sepsis, vasodilation (widening of the blood vessels) makes the blood pressure fall, so the organs get less blood and therefore less oxygen. A patient who is already hypoxaemic risks tissue damage unless oxygen delivery is restored quickly.
Oxygen is the only element among the six that directly corrects hypoxaemia. Intravenous fluid can support the circulation, but it does not raise a low saturation (how much of the haemoglobin in the blood is carrying oxygen). A lactate level measures severity rather than treating anything. Oxygen can be started at once at the bedside, with no sample or result needed.
Oxygen is given to a target saturation of 94% to 98% in most adults, or 88% to 92% in people at risk of hypercapnic respiratory failure (a failure to clear carbon dioxide, which too much oxygen can worsen). One sequencing rule matters: blood cultures are taken before the first antibiotic dose, but they should not delay treatment.
Key facts
- Sepsis Six in adults
- three treatments (oxygen, intravenous antibiotics and intravenous fluids) and three checks (blood cultures, a lactate level and hourly urine output).
- One hour
- all six are to be completed within one hour of recognising sepsis.
- First element
- oxygen, which corrects hypoxaemia when vasodilation is already cutting blood flow and oxygen delivery to the organs.
- Target saturation
- 94% to 98% in most adults, or 88% to 92% in people at risk of hypercapnic respiratory failure.
- Sequencing
- blood cultures are taken before the first antibiotic dose, but they should not delay treatment.
- Lactate level
- a blood test whose rise suggests the tissues are short of blood flow; it shows how sick the patient is but does not raise the oxygen level.
Exam traps
- Intravenous fluid can support the circulation, but it does not correct a low saturation and it is not the element listed first in the Sepsis Six.
- Measuring a lactate level does not come before correcting a low oxygen saturation, because it measures severity rather than treating anything.
- Oxygen is given for hypoxaemia, so giving it to a patient whose saturation is normal, such as 98 per cent, can cause harm without benefit.
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