There is an important document we should be aware of in that case. 

The document we are talking about is something called POLST.

"POLST stands for physician order for life sustaining treatment.  It's a medical order indicating what kind of treatments you would like or not like in case you become unable to make decisions for yourself,” said Dr. Emese Somogyi of Castle Medical Center.

Just when should patients consider using a POLST?

"Generally, POLST  is something for people to think about if they have some serious advanced illness such as advanced cancer that's spreading or end stage heart or lung disease,” she said.

Generally speaking, a POLST differs somewhat from another document that many people have created - the advanced health care directive.

"Advanced health care directives serve two purposes.  One is to make a statement about our wishes for treatment and the other is to designate a power of attorney for health care,” she said.

Another question - does the doctor signing off on the POLST form have to be your primary care physician?

"It doesn't have to be a particular physician.  What's really important is that the person had a detailed discussion of his preferences about treatment and that it got documented,” she said.

And the document?

"It's a bright green form and there's a reason for that.  It's so that it's easily noticeable because sick people live in different places.  Some people live at home, some spend time in hospital or nursing home and this form is valid in all those settings,” she said.