In many ways, it was much easier when people simply expired naturally.

But today, thanks to steady advances in medicine and technology, the dying are kept alive longer, often relatively comfortably, in the sterile confines of a hospital setting.

The majority of Americans die in their community hospital, says Sharon Kaufman, a medical anthropologist at UCSF. She spent two years immersed in that universe — where individuals, families and medical professionals deal with end-of-life decisions day in and out — observing the course of care for about 100 critically ill patients at three Bay Area hospitals.

The result is “…And a Time to Die: How American Hospitals Shape the End of Life,” a 400-page, unblinking look at the realities of modern death. And no matter how carefully we plan, Kaufman notes, the scenario may play out in a completely different fashion.

“I learned how deeply and insidiously the bureaucratic structure of the hospital shapes things,” she says.

Death is “malleable,” she explains in her book; “medicine can manipulate” when death occurs.

“Struggling to find ways to either stave off death or arrange for ‘good’ deaths, hospital staff, together with the powerful technologies that are part of hospitals” can keep patients alive. This “prolonged hovering at the threshold between life and death” is where the patient remains “until it is decided when it is time for them to die.”

This is happening across the country, Kaufman asserts. “It’s really difficult drawing that line” between the “desire to prolong life and yet not suffer an agonizingly prolonged death,” says the San Anselmo resident.

“And it’s getting more difficult,” she adds, as people are living longer. “There isn’t an expectation that, at 85, you need to be old and dying anymore.”

Kaufman, who has studied aging, geriatric healthcare and the ethics of medical practice for some 20 years, is on the joint faculty of medical anthropology at U.C. Berkeley and UCSF. She says her book, published in 2005, is intended for a dual audience.

“For anybody who is going to have a relative who is going to the hospital for the end of life, I wanted it to be a map of what happens in this terrifying … strange period of time.

“I also wanted it to be for medical professionals,” she says, “to enable them to see what they are doing … within this large context.

She writes: “I learned that each patient’s hospital stay is seen by medical personnel through the lens of the passage of time, through the institutional demand to move through time with economic and clinical efficiency.

“Time is the marker for things health professionals think should happen and for things that must get done, and it weighs heavily on everyone who works in a hospital.”

Though religion was not an overriding factor in Kaufman’s book, it did come into play. Some of the patients and their families had religious convictions, and some turned to clergy for help with decision-making and solace.

“I would say that in most hospitals, medical staff encourage this,” she says. “They want families to feel comfortable and to feel free to bring in whatever social or religious support they want. … There is an awareness that people need spiritual support.”

Some families have clergy come to the terminally ill patient’s bedside for “sort of a prefuneral,” she adds, hoping for peace and closure.

Social workers can assist as well, often serving as facilitators between families and physicians.

And nondenominational chaplaincy programs “that draw from all traditions” are becoming more commonplace, she says.

“Even in a historically Jewish hospital where I was born, my kids were born, my father practiced, Mt. Zion [in San Francisco] always served the local African American community and ethnically diverse areas.”

Diversity became an important factor in her work. “I think I can say that, as a Jew, I was very aware of two things: First, the desire to protect life and prolong life is extremely important, and I wanted to see how that would play out.” Also, “I wanted to see ethnic and religious diversity.

“I’m aware that even within Judaism there’s a range of opinion about prolonging life. I knew that there would be an incredible diversity within and among other groups as well.”

Kaufman can certainly relate to the issues in her book. Her parents are aging — her father, Bernard Kaufman, a retired physician, lives in San Francisco, and her mother lives in Jerusalem. (“I go back and forth a lot,” she says before a recent trip.)

And professionally, end-of-life issues comprise “a huge field of work,” she says. “It’s a big concern, because of the way we are prolonging death so routinely with technology people proclaim they do not want.”

Kaufman learned that “you can’t make these [end-of-life] decisions hypothetically.

“When you can’t breathe and you’re 87 and they say, ‘Do you want us to help you breathe?’ you say yes.”

Which leads to new problems. “People go against their own [advance medical] directives, or their relatives do. Physicians in hospitals say they will honor written directives, but when a family member is there, they always defer to what the family members prefer.”

Her advice? “I think it’s very useful and very important for families to talk to one another, as specifically as possible, about what they think they want — knowing that will change,” Kaufman says. “I think the more open the discussion, the better.”

“…And a Time to Die” by Sharon R. Kaufman (400 pages, Scribner, $28).