I have a patient, Mrs. Jones, in her 70s or 80s. She has heart failure and pulmonary oedema (fluid sits in the lungs due to impaired heart pumping function). We loaded her with diuretics (water medication) to offload the fluid. Her oxygen saturations are 78% on air (in a normal person it's >95%). I see her and she's flinging her nasal prongs and oxygen mask off her bed, heaving away, resp rates are high, using accessory muscles of breathing -- she is in respiratory distress.

I talk to her to convince her to take the mask. It's claustrophobic and stinks (literally. The plastic scent is horrible), I know, but she will die within the next few hours if she does not take the mask. She refuses. I offer the nasal prongs -- the next best option -- she refuses. I assess her capacity to make that decision -- she knows without them, she will die. She is unable to tell me why she is so short of breath despite me explaining it's due to the extra fluid (pulmonary oedema). She knows the consequences of her actions, but she is unable to retain information I give her -- she does not have capacity. Is it because she's confused from hypoxia (low oxygen sats) or she's brewing a new infection?

However, I can't physically pin her down and force that mask on her even if she lacks capacity. I'm also aware hypoxia will exacerbate her distress and make her feel worse, so if I can treat that, she might be more amenable to oxygen and become more 'herself' again.

I speak to my consultant on call. He has no alternative suggestion and suggests we, therefore, palliate her if we cannot convince her to take the oxygen. We cannot intubate her just to give her oxygen. She is so frail she will never come off a machine; she is not for resuscitation. She will die that night if this continues.

Luckily the nurses (I love them) are able to convince her an hour or so later to take the oxygen mask. She falls asleep. Oxygen levels maintain at 90%. She lives for another day.

In her case, I can force treatment if I can justify it will save her life because she does not have the ability to make decisions for herself -- I can forcibly treat her under the Adults with Incapacity Act. However, we also have to respect people's wishes if they are strong enough, and certainly flinging pieces of equipment off every time we offer it is a strong enough wish. Short of pinning her arms by her side and keeping that mask on, there were no other options at that particular point in time. It sucks to be so helpless in a situation where the solution is (apparently) so obvious.  And this is a great moment to appreciate my nurses all the more.