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Press Release

November 12, 2018

By Janet Byron, Senior Communications Consultant

Many patients with acute pulmonary embolism — a blood clot that blocks blood flow to the lungs — can be safely discharged to their homes from emergency rooms without harmful effects, a new Kaiser Permanente study shows.

The study, “Increasing outpatient management of emergency department patients with pulmonary embolism: a controlled pragmatic trial,” was published today in Annals of Internal Medicine.

While U.S. and European guidelines recommend the outpatient management of certain pulmonary embolism cases, admission to the hospital has been standard practice in the United States and around the world.

David Vinson, MD, lead author of study in Annals of Internal Medicine

Researchers in Kaiser Permanente’s Clinical Research on Emergency Services and Treatments (CREST) Network evaluated the implementation of a web-based decision support tool called RISTRA (RIsk STRAtification), which incorporates a validated severity index for pulmonary embolism that is completed automatically from the patient’s electronic health record, with a list of risk factors for possible adverse outcomes.

“Our online tool helps emergency room doctors to quickly and easily identify which patients with pulmonary embolism can be safely treated at home, thus avoiding costly and inconvenient hospitalization,” said lead author David R. Vinson, MD, a Kaiser Permanente emergency department doctor and adjunct researcher with the Kaiser Permanente Northern California Division of Research.

Was that a heart attack, or not?

Vinson said that the symptoms of pulmonary embolism can overlap with those of heart attacks, making it more difficult to diagnose. “The most common symptoms of pulmonary embolism are shortness of breath, and chest pain,” he said. “Because of the clot, the lungs have to work extra hard.”

However, tests done in the emergency department, including electrocardiograms and blood tests, can definitively rule out heart attacks, Vinson said. The diagnosis of pulmonary embolism, on the other hand, is usually made with a CT (computed tomography) scan.

The RISTRA tool in the  electronic medical record helps emergency department doctors to make informed decisions about care.

“Then the doctor must decide whether a patient with pulmonary embolism is a good candidate for home care, can be sent to a short-term observation unit, or is best-served by hospitalization.”

Onsite “champions”

The study was conducted in 21 emergency departments in Kaiser Permanente Northern California from January 2014 to April 2015, with 10 intervention and 11 control sites. The RISTRA decision support tool for pulmonary embolism was available to doctors in the 10 intervention sites.

At the intervention sites, doctors were educated about the tool; got positive feedback by email after using the tool; and received a small incentive for each of their first three uses of RISTRA. In addition, a physician “champion” promoted use of the tool at intervention sites.

Left to right: Dustin Mark, MD, David Vinson, MD, and Dustin Ballard, MD, members of the Kaiser Permanente CREST Network of emergency department researchers

“We weren’t directing our physicians’ site-of-care decisions,” said Dustin W. Ballard, MD, MBE, Kaiser Permanente emergency department doctor, adjunct researcher with the Kaiser Permanente Division of Research, and co-author of the study. “We were informing them. We wanted the physicians in conversation with their patients to decide what was the best site of care.”

The study enrolled 881 patients with pulmonary embolism at intervention sites and 822 patients at control sites. In emergency departments with the intervention:

  • 70 percent of doctors with patients with acute pulmonary embolism consulted the RISTRA tool before making their decision on whether to admit the patient.
  • The rate of home discharge for patients with acute pulmonary embolism increased 60 percent, from 17 percent before the intervention to 28 percent afterward.
  • The intervention sites did not have any increase in people with acute pulmonary embolism returning to the emergency department within 5 days or adverse outcomes within 30 days.

$1 billion in possible costs savings

Vinson and co-authors estimate that for every 100 emergency department patients with acute pulmonary embolism, the intervention averted 11 unnecessary hospitalizations.

“With an average hospital stay of three days, costing about $2,300 per day, that would add up to about $80,000 in cost savings per 100 patients,” Vinson said.

In an accompanying editorial, Paul D. Stein, MD, and Mary J. Hughes, DO, of Michigan State University College of Osteopathic Medicine, wrote that despite some challenges in implementing the tool, the benefits of broad implementation in emergency departments would include a significant reduction in health care costs.

“The investigators are to be congratulated for showing the effectiveness of this computer tool that, when intensively promoted, enabled physicians to knowledgeably select a larger proportion of patients for home treatment,” they wrote.

Stein and Hughes pointed out that if all eligible patients with pulmonary embolism seen in U.S. emergency departments were treated at home rather than in the hospital, health care costs would decrease by $1 billion per year.

“The clinical decision support tool for pulmonary embolism benefits all players,” Vinson said. “Physicians receive evidence-based guidance on how to provide optimal care, patients receive the intensity of care that best matches their needs, and the health care system at large is enabled to better manage its resources.”

The study was funded by the Garfield Memorial National Research Fund, The Permanente Medical Group Delivery Science and Physician Researcher programs, Kaiser Permanente Northern California Community Benefit Program, and the Kaiser Permanente Innovation Fund for Technology.

In addition to Vinson and Ballard, co-authors of the study were Dustin G. Mark, MD, Uli Chettipally, MD, MPH, Jie Huang, PhD, Adina S. Rauchwerger, MPH, Mary E. Reed, DrPH, James S. Lin, MD, Mamata V. Kene, MD, MPH, Dana R. Sax, MD, MPH, , Ian D. McLachlan, MD, MPH, , and Andrew R. Elms, MD, all affiliated with Kaiser Permanente’s CREST Network; David H. Wang, MD, Scripps Health, Tamara S. Pleshakov, DO, Kaiser Permanente Los Angeles Medical Center, Cyrus K. Yamin, MD, Kaiser Permanente Oakland Medical Center, Hilary R. Iskin, BA, University of Michigan Medical School, and Ridhima Vemula, BA, University of Cincinnati College of Medicine, all formerly affiliated with the CREST Network; and Donald M. Yealy, MD, University of Pittsburgh School of Medicine.