Patients might be able to make some competent decisions. A pregnant woman gave consent for caesarean section but not for anaesthetic injection prior to the procedure as she was needle phobic. The court decided that the needle phobia has rendered her temporarily incompetent . Capacity is almost certainly task-specific; many people are competent to make certain decisions but not others .
A surgeon faces many challenges as all surgical disciplines continue to advance and a significant part of the society constitute elderly people. Those people require continuous medical care and can be seriously ill . With artificial nutrition and ventilation it is becoming possible to prolong a person's life despite the failure of essential bodily functions. It is always a dilemma when it comes to providing or withholding life prolonging treatment. A decision to prolong life, not euthanasia which is unlawful, of a terminally diseased patient might not be in his/her best interest. The BMA has suggested that extra safeguards should be followed if the person is unable to take a decision for himself or herself and it is believed that continuing to provide ANH (artificial nutrition and hydration), which is considered a medical treatment, is not in his or her best interests .
In any event, when a patient refuses life-saving surgery it would be expected that the English Courts will resolve that doubt in favour of preservation of life . Advanced directives or "living wills" will be binding the surgical practitioners involved in the patient's care if it was proved that the patient was competent when he/she executed the advanced refusal, fits his/her current predicament and the patient had not subsequently changed his mind. Advance directives setting out the kind of care the person would like to receive are not legally binding, but should be influential when deciding what treatment is in the person's best interests. Sections 24 and 25 of the Mental Capacity Act 2005 specifically deal with this issue.
In W Healthcare NHS Trust v H , KH suffered acutely from multiple sclerosis. Although she retained consciousness, she was disorientated and no longer recognized her closest family members. She was fed by a PEG tube through the stomach, could not swallow and was incontinent, which required her to have 24-hour-care. There was evidence by family and friends that she had said if the time came and she could no longer recognize her daughters, she did not want to be kept alive. The feeding tube was dislodged and the argument was whether to reinsert or let her die. The Court found that there was no advanced directive to suggest that she wanted to die by starvation. In contrast, AK a 19-year-old man suffering from motor neuron disease requested that the doctors should remove him from artificial ventilator two weeks after he finally lost the ability to communicate . The Judge was satisfied that they genuinely represent AK considered wishes and should be treated as such.
Another example is Jehovah's Witnesses who specify that they would not consent to receive blood transfusion. In Re E, a child needed urgent blood transusion, for his leukemia, to save his life. Being a devout Jehovah's Witness, he refused to consent for the treatment as well as the parents. Ward J said "In my Judgment, A has by the stand he has taken thus far already been and become a martyr for his faith. One has to admire...he is, he says, prepared to die for his faith...But I regret that I find it essential for his well-being to protect him from himself and his parents, and so I override his and his parents' decision" .
Cases involving anorexic patients are particularly good examples of the rather blurred line between the protection of the competent patient's right to take 'irrational decisions', and the questioning of capacity on the ground of the patient's irrational decision-making. The courts have found anorexics incompetent in a number of cases and have authorized force-feeding without their consent  this is because the disease creates inability to understand, believe and weight treatment information in order to arrive at a choice and thus anorexic patients will commonly fail the Re C test.
DNAR (do not attempt resuscitate) is a widely accepted term in hospitals. Cardiopulmonary resuscitation can in theory be carried out on any person in whom cardiac or respiratory function ceases. A competent patient may choose not to go through this procedure and prefer to die peacefully. The BMA have published detailed guidance on what procedures should be followed when decisions about resuscitation need to be made . NHS Trusts are required to have local policies on resuscitation, along with information about them for patients.
Treatment for most conditions remains imperfect, and research is often carried out to develop new treatments, or compare the effectiveness of existing treatments. It may occasionally be in the best interests of a person who lacks capacity to consent to be entered into a clinical trial of a new treatment, for example if a standard treatment is non-existent, or of very limited effectiveness. Bodies such as the Medical Research Council and the Royal College of Surgeons have suggested that it can be lawful to carry out research on incapacitated adults which will not benefit the individual, as long as this is not against the interests of the individual. Such research might include, for example, carrying a new form of surgery and carrying invasive investigations for the purposes of research into the condition from which the person is suffering. The application of 'Virtue ethics' suggests that only those patients who choose to participate in research after having fully informed consent should be included. Lessons from the past include several worldwide examples especially from North America, the Early 1940's Germany and South America where patients were deemed to have incapacity (due mainly to imprisonment, race or disability) and research was carried out for the "greater good" It is presently deemed unethical and appears to have a distinct eugenic undertone that even today leaves a bitter aftertaste, however well it is disguised as progress.