FORT SILL, Okla. -- Jessica Zeppa, five months pregnant and the wife of a soldier, showed up four times at Reynolds Army Community Hospital in pain, weak, barely able to swallow and fighting a fever.
The last time, she declared that she was not leaving until she could get warm.
Without reviewing her file, nurses sent her home anyway in a wheelchair, with an appointment to see an oral surgeon to extract her wisdom teeth.
Zeppa returned the next day in an ambulance. She was airlifted to a civilian hospital, where despite relentless efforts to save her and her baby, she suffered a miscarriage and died Oct. 22, 2010, of complications from severe sepsis, a bodywide infection.
Medical experts hired by her family said later that because she was young and otherwise healthy, she most likely would have survived had the medical staff at Reynolds properly diagnosed and treated her.
"She was 21 years old," her mother, Shelley Amonett, said. "They let this happen. This is what I want to know: Why did they let it slip? Why?"
The hospital doesn't know, either.
Since 2001, the Defense Department has required military hospitals to conduct safety investigations when patients unexpectedly die or suffer severe injury. The object is to expose and fix systemic errors, often in the most routine procedures, that can have disastrous consequences for the quality of care. Yet there is no evidence of such an inquiry into Zeppa's death.
The Zeppa case is emblematic of persistent lapses in protecting patients that emerged from an examination of the nation's military hospitals, the hub of a sprawling medical network -- entirely separate from the scandal-plagued veterans system -- that cares for the 1.6 million active-duty service members and their families.
Internal documents depict a system in which scrutiny is sporadic and avoidable errors are chronic.
As in the Zeppa case, records indicate that the mandated safety investigations often go undone: From 2011 to 2013, medical workers reported 239 unexpected deaths, but only 100 inquiries were forwarded to the Pentagon's patient-safety center, where analysts recommend how to improve care. Cases involving permanent harm often remained unexamined as well.
At the same time, by several measures considered crucial barometers of patient safety, the military system has had higher than expected rates of harm and complications in two central parts of its business -- maternity care and surgery.
More than 50,000 babies are born at military hospitals each year, and they are twice as likely to be injured during delivery as newborns nationwide, the most recent statistics show. And their mothers were more likely to hemorrhage after childbirth than mothers at civilian hospitals, according to a 2012 analysis conducted for the Pentagon.
In surgery, half of the system's 16 largest hospitals had higher than expected rates of complications over a recent 12-month period, the American College of Surgeons found last year. Four of the busiest hospitals have performed poorly on that metric year after year.
Little known beyond the confines of the military community, the Pentagon's medical system has recently been pushed into the spotlight. In late May, Defense Secretary Chuck Hagel ordered a review of all military hospitals, saying he wanted to determine whether they had the same problems that have shaken the veterans system.
Hagel said the review would study not just access to treatment, the focus of investigations at the veterans hospitals, but also quality of care and patient safety.
Defense Department health officials say their hospitals deliver treatment that is as good as or better than civilian care, while giving military doctors and nurses the experience they may one day need on the battlefield. In interviews, they described their patient-safety system as evolving but robust, even if regulations are not always followed to the letter.
"We strive to be a perfect system, but we are not a perfect system, and we know it," said Dr. Jonathan Woodson, assistant secretary of defense for health affairs. "We must learn from our mistakes and take corrective actions to prevent them from reoccurring."
The examination -- based on Pentagon studies, court records, analyses of thousands of pages of data, and interviews with current and former military health officials and workers -- indicates that the military lags behind many civilian hospital systems in protecting patients from harm.
The reasons, military doctors and nurses said, are rooted in a compartmentalized system of leadership, a culture of interservice secrecy and an overall failure to make patient safety a top priority.
The investigations of unforeseen deaths or permanent harm are regarded as a centerpiece of efforts to make care safer.
Asked about the military's missing inquiries, Dr. James Bagian, director of the University of Michigan's Center for Healthcare Engineering and Patient Safety, said: "If in fact unexpected deaths were reported and ignored, there would appear to be no good answer for that except that someone is sleeping at the switch."
Avoidable errors can and do occur at the best of hospitals, but the military's reports show a steady stream of the sort of mistakes that patient-safety programs are designed to prevent.
The most common errors are strikingly prosaic -- the unread file, the unheeded distress call, the doctor on one floor not talking to the doctor on another. But there are also these, sprinkled through the Pentagon's 2011 and 2012 patient-safety reports:
• A viable fetus died after a surgeon operated on the wrong part of the mother's body.
• A 41-year-old woman's healthy thyroid gland was removed because someone else's biopsy result had been recorded on her chart.
• A 54-year-old retired officer suffered acute kidney failure and permanent hearing loss after an incorrect dose of chemotherapy.
Such treatment failures are known as "never events" because they are so grave and preventable. They do not happen frequently, but a persistent rate of such mistakes can indicate broader patterns of slipshod care.
Malpractice suits also can be a rough indicator of risk. From 2006-10, the government paid an annual average of more than $100 million in malpractice claims from surgical, maternity and neonatal care, records show.
It would be paying far more if not for one salient reality of military health care: Active-duty service members are required to use military hospitals and clinics, but unlike the other patients, they cannot sue. If they could, the Congressional Budget Office estimated in 2010, the military's paid claims would triple.
Experience in civilian hospitals and in the veterans system has shown that stricter procedures and more sophisticated surveillance can limit errors, sometimes markedly. Among some in the military network, concerns about patient safety are long-standing, if rarely acknowledged in public.
But calls for change have consistently foundered in bureaucracy.
The military heath system is split into three major branches, with the Army, Navy and Air Force each controlling its own hospitals and clinics. The Pentagon's Defense Health Agency also runs the Walter Reed National Military Medical Center and Fort Belvoir Community Hospital, both outside Washington.
Any systemwide change involves a carefully calibrated consensus of three equally ranked surgeons general, as well as the Defense Health Agency. Woodson, who oversees the system, cannot order the surgeons general to act. He can only recommend.
Progress can be glacial. In 2007, for example, the military started rewriting regulations for handling events that harmed or endangered patients. It finished in October.
Several former Pentagon officials said embarrassing statistics were often filtered out, glossed over or buried in larger data sets before they reached senior health leaders. Two measures used in major civilian hospitals to monitor quality of care -- rates of death and readmission, adjusted for seriousness of illness -- are simply not tracked.
"The patient-safety system is broken," Dr. Mary Lopez, a former staff officer for health policy and services under the Army surgeon general, said in an interview. "It has no teeth. Reports are submitted, but patient-safety offices have no authority. People rarely talk to each other."
Medical experts hired by the family's lawyers said that had the Fort Sill doctors recognized that Jessica Zeppa was suffering from septic shock and immediately hospitalized and aggressively treated her, she and the baby probably would have survived. The government's experts disagreed, noting that civilian doctors had been unable to save Zeppa during five weeks of treatment.
Justice Department lawyers called Zeppa's death a "unique and tragic case but not a case of bad and actionable medicine."
Beyond the risk-management assessment, they said, they knew of no other inquiry. That left any missteps that contributed to her death unexplained.
"She was really pretty, and she had a really big heart," James Zeppa, Zeppa's husband, said.
Now, he said, he no longer trusts military medicine.
Jessica Zeppa's father, Mike Amonett, had one thing to say about the Fort Sill hospital: "I just want that place shut down."
Information for this article was contributed by Kitty Bennett of The New York Times.
A Section on 06/29/2014