Emergency physicians have historically lacked validated tools for determining which patients with shortness of breath associated with acute heart failure should be admitted and which could be safely discharged. Now, a clinical decision tool may provide a map of the best course to take.
Arising from the distinguished Ottawa Hospital Research Institute, the Ottawa Heart Failure Risk Scale was validated in a study recently reported in Academic Emergency Medicine. (2017;24:316.) Starting with 40 different criteria, Ian Stiell, MD, MSc, a senior scientist in clinical epidemiology at the Ottawa Hospital Research Institute, and his colleagues ended up with a scale of 10 items. They applied the risk scale to 1,100 patients (average age, 77.7) seen in the emergency departments of six tertiary hospitals to validate it.
Emergency physicians evaluated the symptoms of the heart failure patients against the 10 criteria, measured quantitative NT-proBNP when possible, and then followed them for 30 days for severe adverse events. These included death within 30 days, admission to a monitored unit, intubation, noninvasive ventilation, myocardial infarction, and relapse resulting in hospital admission within 14 days.
“It was quite accurate in predicting who will have a bad outcome,” said Dr. Stiell, also a distinguished professor and the clinical research chair in emergency medicine at the University of Ottawa. “Emergency physicians can use that information when making their decision about sending a patient with acute heart failure home.”
Dr. Stiell and his colleagues said physicians should not rely solely on the risk scale in making their decisions. (See table for the criteria included and the values assigned to them.)
Severe Adverse Events
Patients who could not be evaluated by the criteria were excluded from the study as were those who did not have the symptoms associated with acute failure or were too ill to be considered for discharge after two to 12 hours of management in the emergency department. These criteria and others described in the report found that 3,130 of 4,999 patients presenting with shortness of breath were not eligible for the study. A total of 769 of the 1,869 who met eligibility criteria were not enrolled because they presented when the research staff was not on duty or staff were busy with patient care.
Fifty-seven percent of remaining patients were admitted to the hospital, and nearly 43 percent were discharged home. The severe adverse event rate was 15.5 percent overall — 19.4 percent of admitted patients and 10.2 percent for discharged ones. That rate was 17.4 percent for those who had NT-proBNP values. Forty-one patients died during the study, and 16 (39%) had been discharged home from the ED or after hospital admission.
“I am advocating putting this into clinical practice,” said Dr. Stiell. “Something is better than nothing. We are not telling anyone who to admit and who not to admit, but we are telling them which patients are at higher risk.”
The total score on the risk scale gives physicians a handle on which patients face low risks and which face high ones. Patients with a total score of 0 had a risk of 2.8 percent of serious adverse events in 14 days and were placed in the low-risk category. Patients with scores of 1 and 2 had risk scores of 5.1 percent and 9.2 percent, respectively, and were considered medium risk. Those with scores of 3 and 4 were considered high risk with risk scores of 15.9 percent and 26.1 percent, respectively. Those with total scores of 5 to 9, whose risk scores ranged from 39.8 percent to 89 percent, were considered at very high risk of serious adverse events within 14 days.
“It is up to the doctor to decide who to admit and who to send home,” Dr. Stiell said. “This is the most sophisticated scale we've ever developed. I hope it will prove to be useful.”
Impact on Care
This study validates the scale, he said, but it will take time to see what impact it has on practice and patient care, Dr. Stiell said, noting that the rate of hospitalization is lower in Canadian patients than in those in the United States.
The proposed scale has generated considerable interest across the blogosphere. An evaluation in Medscape by Bryan H. Lassner, MD, and Andrea S. Kreiger, MD, calls the scale “an important first step” in helping to risk-stratify acute heart failure patients, but they said they doubt it justifies changing current emergency department practices. “What this study cannot tell us is whether the likelihood of these [serious adverse events] would be altered by an inpatient admission,” the reviewers wrote. (http://wb.md/2p3NWlJ.)
They also noted that the study may not apply to U.S. emergency departments. Canadian hospitals have disposition times as long as 12 hours and often lack an observation unit, and they also admit only 38 percent of acute heart failure patients compared with 80 percent at U.S. hospitals.
Dr. Stiell agreed that the scale may not have widespread use in the United States, where he said he sees resistance to the notion that you can identify the people who can go home. “It's a more complicated health care system,” he said, noting that pressures in the United States are often different from those that affect Canadian medicine.
Justin Morgenstern, MD, who wrote a guest blog post on the study for The Skeptics' Guide to EM, concluded that the Ottawa Heart Failure Risk Scale can probably help make disposition decisions by accurately predicting the 30-day rate of serious adverse events in patients with acute heart failure. (http://bit.ly/2pZAXhY.) “However, we would love to see this scale validated in a [randomized controlled trial] so that we can see patient-oriented outcomes before it is used widely,” wrote Dr. Morgenstern, an emergency physician who is the director of simulation education at Markham Stouffville Hospital in Ontario and the author of the blog, First10EM.com.
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