Brenda Nelson hurried though the doors of Martin Luther King Jr./Drew Medical Center in October, toting a container of gumbo soup for her son, Mario. She expected him home soon.

To her surprise, she was told that Mario, 28, was in intensive care. There, a security guard repeatedly refused to let her in. When she finally was allowed through an hour later, nobody told her what she would find.

Mario was dead, his eyes and mouth open.

"I screamed and hollered," she said recently, her hands trembling. "I tried to pull my baby out of the bed."

Then she closed his eyes.

A nurse told Nelson that Mario — the family's chief party planner and cook, and a onetime church choir director — had suffered from AIDS, something she hadn't known. The immediate cause of death was respiratory failure brought on by pneumonia.

What Nelson was not told, until The Times reported it five days later, was that the nurse assigned to keep constant watch over Mario had not. She had silenced the alarm on his vital-signs monitor, then failed to notice his heartbeat fading, according to the nurse's suspension letter filed in her Civil Service records.

Nor was Nelson told that the nurse had allegedly falsified her son's medical chart. According to Los Angeles County health officials, the nurse indicated that she found Mario stable at 6 p.m. — more than an hour after he had died.

"She took it in her hands to play God," said Nelson, who has sued the county, which owns King/Drew.

Mario's death was no isolated incident. Three King/Drew patients, all hooked up to monitors, died last year after nurses failed to notice their declining vital signs, state and federal inspectors found.

The nursing department is often considered the heart of a hospital; its failings alone can incapacitate the entire institution. The frequency of lapses in King/Drew's nursing department suggests a systemic problem, one that goes beyond mere individual shortcomings.

In fact, a Times investigation found that such deep failings extend well beyond nursing, to at least three other areas.

Mistakes and neglect at times have debilitated King/Drew's pharmacy and doctor-training programs, which affect nearly every patient admitted. And the newspaper found the small but essential department of orthopedic surgery to be crippled by employee misbehavior — absenteeism, profiteering, even the commission of felonies in off hours.

The fault, hospital experts say, lies with the institution's overall leadership.

Unless leaders can identify and fix what is broken, a hospital cannot operate safely, said Dr. Donald Berwick, president of the Boston-based Institute for Healthcare Improvement. Otherwise, he said, it's like insisting, "My car is fine except for the brakes."

Until recently, the Los Angeles County Board of Supervisors, King/Drew's governing body, has balked at wholesale repairs. Over the years, as the evidence has piled up in audits, malpractice cases, internal memos and reports from regulators, the board has largely stood by, seemingly paralyzed.

"Fundamentally, someone has to step up to the plate and lead the people out of the morass that they're in," said Dr. Kenneth W. Kizer, president of the National Quality Forum, a nonprofit group seeking to improve healthcare.

Orthopedic surgery

Orthopedic surgeons are the carpenters of medicine, called in to repair limbs shattered by bullets or snapped in car wrecks. They tend to the aching joints of the elderly and the torn ligaments of the weekend warriors.