AT ATS 2017

WASHINGTON (FRONTLINE MEDICAL NEWS) – A new way to semiquantitatively score chest x-rays that takes into account lung density and consolidation may be a useful adjunct to current methods for assessing severity of acute respiratory distress syndrome.

The score, know as the Radiographic Assessment of Lung Edema (RALE) score, showed good correlations with lung edema, the severity of acute respiratory distress syndrome (ARDS), and response to fluid management resulting in reduced pulmonary edema, Melissa A. Warren, MD , said at an international conference of the American Thoracic Society.

“The chest x-ray may be an untapped resource for detecting ARDS severity and prognosis,” said Dr. Warren, a pulmonologist at Vanderbilt University, Nashville, Tenn. “Currently, no noninvasive and accurate measurement exists to quantify pulmonary edema.”

The RALE score that Dr. Warren and her associates devised rates a patient’s chest x-ray for two parameters: consolidation, which is based on the extent of alveolar opacity in each of the four lung quadrants (left upper, left lower, right upper, and right lower), and a density score that is based on the density of alveolar opacity in each quadrant.

The consolidation score for each quadrant is rated on a 0-4 scale with 0 corresponding to no opacity, 1 for 1%-24% opacity, 2 for 25%-49% opacity, 3 for 50%-75% opacity, and 4 for more than 75%. The density score is rated on a scale of 1-3 with 1 for hazy opacity, 2 for moderate opacity, and 3 for dense opacity. The score for each quadrant is obtained by multiplying the extent score by the density score. A patient’s total RALE score sums the scores from all four quadrants.

The researchers ran three tests of the clinical relevance of this scoring system. First, they used it to score chest x-rays of 72 preprocurement lungs donated for transplant but unable to be used for that purpose, and compared the scores with the extent of lung edema measured by the actual weight of each explanted lung. This showed high correlation between the scores and the amount of edema, Dr. Warren reported .

Next they assessed the RALE score as a marker of ARDS by retrospectively calculating the scores of 174 patients with baseline chest x-rays enrolled in the Fluids and Catheters Treatment Trial ( FACTT ) ( N Engl J Med. 2006;354[24]:2564-75 ). This analysis showed that patients with the highest RALE scores had significantly worse survival during 90-day follow-up, compared with the patients with the lowest scores.

Finally, the researchers assessed how the RALE score changed in response to either the liberal or conservative fluid management approaches tested in FACTT. This showed that at baseline the average RALE scores were similar among 92 patients randomized to the liberal fluid management treatment arm and 82 patients assigned to the conservative fluid management arm. But after 3 days of treatment, patients in the conservative arm showed a roughly one third reduction in their average RALE score, while patients in the liberal fluid arm showed virtually no change in their score.

“A conservative fluid management strategy favorably impacted the RALE score, reflecting a decrease in pulmonary edema,” Dr. Warren concluded.

mzoler@frontlinemedcom.com

On Twitter @mitchelzoler

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