Most ethical issues faced by doctors arise at the end of a patient's life. This particularly applies to respiratory physicians, where difficult decisions about the appropriateness of treatment and the prolongation of life in patients ＿＿（31）＿＿ chronic underlying lung diseases may need to be made. In some situations artificial ventilation may prolong the dying process, but life has a natural end and the potential to prolong life in the intensive care unit can sometimes ＿＿（32）＿＿ dilemmas. The General Medical Council in the UK states that doctors have an obligation to respect human life, protect the health of their patients, and put their patients' best interests first. This means ＿＿（33）＿＿ treatment where the benefits outweigh any risks, and avoiding treatments that carry no net gain to the patient. If a patient wishes to have a treatment that in the doctor's view is not indicated, the doctor and medical team are under no ethical or legal ＿＿（34）＿＿ to provide it (though the patient's right to a second opinion must be respected). When it is determined that the treatment is not in the best interests of the patient, there is no ethical distinction between withholding and withdrawing treatment. This principle may be used to ＿＿（35）＿＿ the decision not to initiate the treatment. In such cases, the focus should shift to providing comfort and supportive care.