Bedside Imaging Can Gauge Dysfunction in Pulmonary Embolism

Kate Johnson

October 31, 2016

CORRECTED November 8, 2016 // LOS ANGELES — When treating patients with acute pulmonary embolism, pulmonary and critical care fellows and intensivists can use rapid point-of-care ultrasound as a triage device, according to results from a single-center study.

"In all honesty, with minimal training, fellows can do a pretty good job," said lead investigator Jason Filopei, MD, from Mount Sinai Beth Israel Hospital in New York City.

"Normally, the exam is done by cardiologists, who are not routinely available. So how can you do it safely and quickly and have it available all the time? That's where having trainees who are adept at doing the procedure comes in," said senior investigator Samuel Acquah, MD, also from Mount Sinai Beth Israel Hospital.

"With some basic training, fellows are able to perform the test appropriately," he reported.

But not everyone agrees. "I would definitely downgrade these conclusions," said Alessandro Squizzato, MD, PhD, from the Research Center on Thromboembolic Disorders and Antithrombotic Therapies at the University of Insubria in Varese, Italy.

"The accuracy of well-trained pulmonary and critical care fellows in this study is still suboptimal," he told Medscape Medical News.

The findings were presented as a poster here at CHEST 2016.

In the study, bedside ultrasound was performed by pulmonary and critical care fellows who had attended a 3-day introductory course on point-of-care ultrasound.

The fellows evaluated right ventricular size and function at the bedsides of 60 patients, explained Dr Filopei.

For acute pulmonary embolism patients, risk of death is greatest in the first 24 hours. On average, point-of-care ultrasound was performed 1 day earlier than transthoracic echocardiogram.

For comparison, all patients also underwent a transthoracic echocardiogram performed by an expert sonographer, which was analyzed by a board-certified cardiologist.

In addition, 44 of the bedside ultrasound examinations were available for over-read by a pulmonary and critical care attending physician who had more than 5 years of ultrasound experience.

Compared with the accuracy of transthoracic echocardiography performed by an expert sonographer, "the diagnostic accuracy of pulmonary and critical care fellows was acceptable," Dr Filopei reported. "They're hitting diagnostic accuracies of about 80% overall, when you combine sensitivity and specificity."

"And intensivists did much better," he added, with accuracies of "greater than 90% in many cases."

But according to Dr Squizzato — who was involved in a recent study of point-of-care ultrasound for the diagnosis of pulmonary embolism (Crit Ultrasound J. 2015;7:7) — "a sensitivity of 93% means a 7% false-negative rate, and a specificity of 86% means a 14% false-positive rate."

That is "too many false positives and false negatives," he said. "For pulmonary embolism, a potentially fatal disease, this is not acceptable from my point of view."

But timing is an important consideration in the equation, Dr Filopei pointed out.

"For acute pulmonary embolism patients, risk of death is greatest in the first 24 hours. On average, point-of-care ultrasound was performed 1 day earlier than transthoracic echocardiogram, with an average time difference of 25 hours and 31 minutes," he explained.

This is a viable option "when you don't have a sonographer accessible to appropriately risk-stratify but you do have boots on the ground that are capable of doing it with some level of training," Dr Filopei said. "Intensivists and pulmonary fellows can do it safely with a high degree of accuracy."

Dr Filopei, Dr Acquah, and Dr Squizzato have disclosed no relevant financial relationships.

CHEST 2016: American College of Chest Physicians Annual Meeting. Presented October 26, 2016.

Editor's note : The original version of this story incorrectly stated that point-of-care ultrasound was used for diagnosis. In fact, it is used for the triage of patients with acute pulmonary embolism.


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