The article offers an analysis based on a clarification of several fundamental concepts that offer a frame of reference: health as a balance or harmony between what is physical, mental, social and spiritual and the environment where a person lives and develops; illness as disintegration or a rupture of the unity of the person; and nursing care. The effects of illness on the patient and the nursing professional are examined, as are the factors that cause stress in a critical-care unit. The bioethical principles of charity, no malice, autonomy and justice are compared to some of the values found in professional nursing, such as discretion and respect for privacy, the ability to listen, confidentiality, truthfulness and the principle of non-abandonment The concept of futility is examined in light of those principles, taking into account factors such as physiological utility, prognosis of the illness and assessment of the benefit. Because death is a daily possibility and occurs in intensive care units, the subject of dying with dignity cannot be ignored. Death has been displaced from the home to the hospital, and has ceased to be a natural process. The professional nurse is obliged to take the lead in ensuring respect for the rights of terminally ill patients, which contribute to a dignified death that is understood properly. This analysis can help to extol the human condition of those who work in health areas, which is put to the test during the daily care of patients who are critically or terminally ill.