Whatever you may think about Terri Schiavo’s saga it provides a useful lesson: By acting ahead of time, you can control what will happen to you when the end approaches even if an accident or illness renders you unable to make health care decisions for yourself.

But that’s not quite as easy as some news reports have suggested.

It requires, for instance, two key documents. The first is an advance health care directive, sometimes called a living will. The second is a durable power of attorney for health care. The living will tells what you want done and don’t want done to you. The durable power of attorney identifies the person whom you select as your agent, to make health care decisions if the time comes when you are unable to do so.

A 1995 Maine law, the Uniform Health Care Decisions Act, provides a model form, which may be altered, expanded or discarded altogether. Other forms are available from hospitals, doctors’ offices and commercial suppliers of legal forms.

The Maine state form provides basic wording for the most important decision of all: whether to direct health care providers and others involved in your care to “provide, withhold or withdraw treatment” in accordance with a marked choice whether or

not to prolong life. Here is the state’s model wording:

“Choice Not to Prolong Life: I do not want my life to be prolonged if (i) I have an incurable and irreversible condition that will result in my death within a relatively short time, (ii) I become unconscious and, to a reasonable degree of medical certainty, I will not regain consciousness, or (iii) the likely risks and burdens of treatment would outweigh the expected benefits. OR

“Choice to Prolong Life: I want my life to be prolonged as long as possible within the limits of generally accepted health-care standards.” The form goes on to require that artificial nutrition and hydration be provided, withheld or withdrawn in accordance with the basic choice above, unless the signer specifies such steps regardless of his or her condition and regardless of the basic choice.

The durable power of attorney designates an agent (and often an alternate) to make health care decisions if the signer is incapacitated. The word “durable” is essential, since an ordi-nary power of attorney expires when the principal loses the ability to make important decisions.

Both documents should be properly signed, dated and witnessed. But they can’t be honored unless they are known to the people concerned with your health care. So copies should be distributed not only to members of your family and your lawyer but also to your

doctor and your hospital. Finally, they should be reviewed from time to time. Right now is a good time to do so.