Bedside Echo Could Facilitate ER Diagnosis of Pulmonary Embolism

October 22, 2013

By Will Boggs, MD

NEW YORK (Reuters Health) Oct 22 - Identification of right ventricular dilatation on bedside echocardiography by emergency physicians may aid in the diagnosis of pulmonary embolism (PE), according to a prospective observational study.

"A bedside echo in a patient that you suspect has a PE may expedite both the diagnosis and treatment," said senior author Dr. Kristin Carmody from New York University School of Medicine.

"Right ventricular dilatation or dysfunction that is visualized on a bedside echo in patients who have high suspicion of PE or moderate suspicion with delays to obtain definitive imaging may better guide physicians in beginning early anticoagulation," she told Reuters Health by email.

Around 1.35 million Americans a year have a pulmonary embolism, resulting in at least 25,000 PE-related deaths annually. Early treatment is critical to better outcomes.

Dr. Carmody and colleagues investigated whether bedside echocardiography in 146 patients with moderate to high risk (or confirmed) PE could reliably identify those who have right ventricular dysfunction, possibly leading to earlier diagnosis and treatment.

Four trained physicians performed all of the bedside ultrasounds (one had formal emergency ultrasound fellowship training; three had a one-month ultrasound rotation during residency and had completed a minimum 25 cardiac ultrasounds and an additional 20 hours of cardiac ultrasound training before their participation in the study).

The prevalence of PE in these 146 patients was 21% (30/146), according to the report, online September 30 in Annals of Emergency Medicine.

Fifteen of the 30 patients with PE had right ventricular dilatation on bedside echocardiography, whereas two of 116 patients without a PE had right ventricular dilatation, giving this finding a sensitivity of 50%, specificity of 98%, and positive and negative predictive values of 88% for the diagnosis of PE.

Most of the 15 patients with confirmed PE and right ventricular dilatation had proximal clots, whereas most of the 15 patients with confirmed PE and a normal right ventricular:left ventricular ratio had more distal clots.

Among the five patients who presented with a confirmed PE prior to enrollment in the study, one had signs of right ventricular dilatation and four had a normal right ventricular:left ventricular ratio on the bedside echocardiography.

Additional echocardiographic findings included right ventricular hypokinesis (11 patients, 10 of whom had PE), McConnell's sign (six patients, all with PE), and paradoxical septal motion (eight patients, all with PE).

Sensitivities for these additional findings were 33% and lower, whereas specificities were 99% or 100%.

"These results may not be easily reproduced by other emergency physicians who do not have ultrasound requirements in residency, are further removed from their ultrasound training, or who do not specifically receive training in cardiac sonography," the researchers say.

"The trend is to expand POCUS (point of care ultrasound) training into not just academic, but community settings as well," Dr. Carmody said. "EM and other physicians should have at least basic training in echo these days and other ultrasound applications. I regularly teach my residents to evaluate for signs of RV strain on echo and believe it is a useful skill to master."

"The bedside echo is not meant to delay other diagnostic testing," she added. "In reality, a definitive test to diagnose a PE does not get done immediately when a patient arrives to the emergency department. There are delays due to radiology wait times and other factors, such as waiting for a creatinine level to come back. If the bedside echo provides useful information, such as signs of RV strain, the physician can act quicker and expedite treatment."

Dr. Erol �nl�er, who was not involved in the new work, said bedside echocardiography (BECH) can be helpful in patients with dyspnea.

"In patients with suspected PE, we have three options in our hands, one is massive PE with central location (patients with shock), the other is submassive PE with central location (patients with stabile vital signs), and segmental or peripheral emboli (patients with stabile vital signs)," Dr. �nl�er, from Izmir Katip �elebi University Atat�rk Research and Training Hospital in Turkey, told Reuters Health by email. "You can pick up two of the three groups of patients (massive and submassive ones) with the BECH."

"But the absence of any finding in BECH does not exclude the diagnosis of peripheral PE," he added. "By performing BECH in patients with suspected PE, you can easily exclude or include the other causes of dyspnea."

Dr. Natale Daniele Brunetti from the University of Foggia, Italy, also praised the technique in an email to Reuters Health.

"Bedside echocardiography for the prompt diagnosis of acute pulmonary embolism is a cheap, surely feasible approach, which requires a very short training," said Dr. Brunetti, who was not part of the new study. "Inter-observer variability is very low and the method is reliable. Bedside echocardiography is the cheap and fast alternative to CT-scan, which is much more expensive and time-consuming."

"Bedside echocardiography should immediately follow the patient's examination and history," Dr. Brunetti said. "Guidelines released by the European Society of Cardiology already prescribe bedside echocardiography as first-line step in diagnostic work-up of subjects with a suspected high risk of acute pulmonary embolism. This confirmatory study provides interesting data on diagnostic accuracy of this method."


Ann Emerg Med 2013.


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