Thanks to advancements of medical science, there are many artificial means of prolonging the lives of individuals with terminal medical conditions long past the time that they would ordinarily pass away. However, not everyone wants their lives prolonged indefinitely when the quality is so severely diminished. 

As a patient, you have the right to refuse certain end-of-life treatments. However, you may not be in a condition to express your wishes. A health care directive provides instructions regarding the treatments that you do and do not want to receive. The National Institute on Aging provides some specific examples of such treatments. 

Artificial nutrition and hydration 

Your condition may deteriorate to the point where you are no longer able to eat or drink on your own. Doctors may provide intravenous fluids to keep you hydrated. Alternative feeding methods include surgically inserting a tube directly into your stomach or threading a tube through your nose and into your alimentary tract to deliver nourishment directly into your stomach. Another alternative method of feeding, though not exactly artificial, is feeding by hand, also called assisted oral feeding. However, this may not be practical if you have difficulty swallowing. 

Ventilation 

If you have difficulty breathing on your own, doctors may hook you up to a ventilator, which is a machine that aids with respiration. Artificial respiration requires the insertion of a tube into your windpipe. If required on a long-term basis, a surgical procedure may be necessary to insert the tube permanently. You can include a do-not-intubate order in your health care directive if you do not want to receive this type of treatment. 

Cardiopulmonary resuscitation 

The purpose of CPR is to restore breathing and circulation after it has stopped. If you do not want doctors to attempt to bring you back after a cardiac arrest or breathing cessation, your health care directive should include a do-not-resuscitate order. 

In addition to these life-saving treatments, your health care directive can also include instructions about comfort care, which are treatments to relieve your suffering at the end of your life.