The decision to end someone's life support is not one that can be taken lightly, and determining the most ethical course of action can be extremely difficult.
The case of Archie Battersbee has illustrated just how complex, divisive and heartbreaking it can be.
The 12-year-old was found unconscious at his home in Southend, Essex in April after suffering traumatic brain injuries - which his mum suspects was due to taking part in an online challenge - and he has not regained consciousness since.
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He is being kept alive by a combination of medical interventions, including ventilation and drug treatments, at the Royal London Hospital in Whitechapel, east London, but a High Court judge has ruled that he should be allowed to die.
His parents have continually fought for the decision to be overturned and are currently waiting to hear from the European Court of Human Rights after making a last-ditch bid to postpone the withdrawal of his life support.
Mehrunisha Suleman, director of medical ethics and law education at the Ethox Centre, University of Oxford, has explained that clinical teams, their ethical standards, and the UK legal system all currently include a presumption in favour of prolonging life; but after the initial life-saving medical intervention is made, doctors must assess the outlook for the patient.
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In a piece for The Guardian, she said: "The questions they would be looking to answer include: what is the extent of the patient's illness or injury? How is their underlying health? Do they have physical reserves that will help their recovery? How likely are they to recover? If they can recover, what will be their quality of life? If they are unlikely to recover, then what is their current condition? What are the likely benefit and burdens associated with the medical interventions they are currently receiving?
"Clinical teams also assess what a patient's wishes would be and whether they would have a preference for medical intervention being continued or withdrawn."
Suleman said clinical teams determine life support should be withdrawn when they consider the patient to be dead, or when they consider continued intervention to be unethically harmful.
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"'Best interest' decisions involve delicate deliberations on the patient's condition, and are some of the hardest decisions that clinical teams are required to make," she said.
Establishing the degree of suffering an unconscious patient is going through is not easy, and as such, teams of experts repeatedly monitor scans and tests, sometimes for months.
Suleman concluded: "Such consideration and careful titration reveals medicine more as an art than a science. There is no litmus test or easy read-out of what to do when a patient is unconscious and requires artificial means to stay alive.
"In the case of children, in the UK, 'best interests' decisions are weighted even more heavily towards sustaining life.
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"As such, a decision to withdraw intervention from a child is likely to rely very heavily on a clinical team's judgment of such intervention being harmful and providing no chance of enabling a life through unsupported means."