Barbara Bush’s decision to stop further medical treatment and choose instead to be at home surrounded by loved ones is focusing attention on “comfort care.”

A family spokesman did not mention a specific illness when referring to her failing health on Sunday, but the former first lady, who is 92, suffers from congestive heart failure and chronic obstructive pulmonary disease (COPD).

In basic terms, comfort care helps or soothes a person who is dying, with doctors preventing or relieving the patient’s suffering as much as possible while respecting his or her wishes, according to the National Institute on Aging.

The emphasis is on treating symptoms rather than focusing on life-prolonging measures, said Dr. Sucharita Kher, a pulmonologist and director of the Outpatient Pulmonary Clinic at Tufts Medical Center in Boston.

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“Comfort care doesn’t mean hastening death or prolonging death, but really allowing a natural death — as natural as possible — and making the patient pain-free and anxiety-free along the way,” Kher told TODAY. She is not treating Mrs. Bush, but commented in general.

For COPD patients, the biggest problem is usually shortness of breath, Kher noted. COPD, which includes chronic bronchitis and emphysema, is a chronic lung disease that makes it hard to breathe and is the third leading cause of death in the U.S., according to the American Lung Association.

As part of comfort care, doctors can alleviate patients’ shortness of breath with oxygen or give medications such as opioids to allow them to breathe more comfortably, Kher said. Opioids can also be used to manage pain.

The decision to move from standard care to comfort care usually starts with a conversation between the patient and the physician, and then ultimately involves the family, Kher noted. Indeed, Mrs. Bush made her decision after consulting with doctors and family members, her spokesman said. The discussion usually includes “do not resuscitate” instructions so that patients do not receive CPR or other life-saving measures if their heart stops, for instance, Kher said.

The patient receiving comfort care can be at home, at a hospital or in a hospice house, depending on what he or she prefers. How much longer they'll live depends on each person and how sick they are, Kher noted.

In Kher’s experience as a pulmonologist, opting for comfort care is not uncommon among patients with COPD, particularly in the last stages of the disease, when it severely impacts a person’s quality of life. Patients often have trouble doing basic everyday things, like getting out of bed, showering or making a meal.

Still, COPD patients opt for comfort care less frequently than patients with a terminal cancer diagnosis, Kher said.

“It’s hard to put a timeline on how much time you have left to live with COPD,” she said. “(But) once you start getting to the point where, even when you’re at home, you can’t breathe very well and you’re required to come in and out of the hospital a lot, that’s the time when a doctor should start to think about, ‘Is this what the patient wants?’ — assuming that medically, treatments have been exhausted.”

Mrs. Bush made the decision to focus on comfort care after a series of recent hospitalizations, her spokesman said Sunday. “She is surrounded by a family she adores and appreciates the many kind messages and especially the prayers she is receiving,” the statement noted.

TODAY correspondent Jenna Bush Hager said she spoke to her grandmother on Sunday night and described Mrs. Bush as being in "great spirits."

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