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