Ideally, an individual at the end of life should be comfortable and free of any distressing symptoms. But the transition to death, just like life's start, is hard work. Just as a woman's body knows how to give birth, the human body knows instinctively how to die, but it doesn't always do so without pain or discomfort.
There are common symptoms that often occur at the end of life, and if they are recognized and managed early on, the individual will be better able to do the important work of dying.
Pain is probably the most feared symptom at the end of life. Not every illness that leads to death causes pain, but other underlying conditions may still exist -- an individual dying of heart failure who also has arthritis, for example. Other diseases, like cancer, usually do cause pain. Whatever the illness is, the ability to recognize and help manage pain is essential.
Anxiety is perfectly normal and quite common at the end of life. We would expect an individual to feel some level of anxiety while experiencing pain or shortness of breath, but anxiety can occur anytime, even without another distressing symptom.
Unfortunately, there isn't much you can do about a decreased appetite at the end of life. As the body naturally shuts down and prepares for death, it no longer needs the calories and nutrition that food provides. If you are concerned about hunger or thirst, you can read more about decreased appetite, increasing food intake, and artificial feedings.
Illnesses, medications, and other treatments can often lead to nausea with or without vomiting. This can be a really troubling symptom for the individual experiencing it, and for caregivers who may have to clean it up.
If you've ever been constipated, you know how horribly uncomfortable it can be. It's definitely not something anyone wants to experience in their final weeks or days. Medications used to treat pain and shortness of breath can cause constipation, as can lack of activity, decreased fiber and fluid intake, and disease processes. Constipation is a symptom you have to stay on top of to prevent it from becoming severe.
Confusion, agitation, and sleeplessness can occur in some individuals at the end of life. Delirium can be caused by disease process, medications, or a number of other things.
As much as I detest calling this symptom the "death rattle," it does create a pretty accurate visual of the symptom. End-stage wet respirations is the medical term for secretions that build up in the airway when an individual becomes too weak to clear those secreations out. The accumulation of mucous and fluids causes a rattling sound with breathing and is probably more distressing to the individual's loved ones.