'Euthanasia and assisted suicide are different from withholding or withdrawing life-sustaining treatment in accordance with good medical practice by a medical practitioner. When treatment is withheld or withdrawn in these circumstances, and a patient subsequently dies, the law classifies the cause of death as the patient’s underlying condition and not the actions of others'. 
Decision making at the end of life can often involve very difficult and emotional decisions about whether to start or stop a treatment. For example, whether or not to start mechanical ventilation or whether to stop PEG feeding. These decisions need to consider whether something is burdensome for the patient – in other words, quality of life.
Nurses are often involved in the debates surrounding the withholding or withdrawal of treatment and there are often conflicting views in decision making. Ethical, cultural, religious and moral factors are enmeshed in these decisions and there are also sometimes worries about legal implications.  One study in an ICU setting found that central to the theme of withdrawing treatment was working with the family; consistent communication is a key factor.