Chest
Volume 127, Issue 5, May 2005, Pages 1690-1695
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Clinical Investigations
“Ultrasound Comet-Tail Images”: A Marker Of Pulmonary Edema: A Comparative Study With Wedge Pressure And Extravascular Lung Water

https://doi.org/10.1378/chest.127.5.1690Get rights and content

Background

Echographic examination of the lung surface may reveal multiple “comet-tail images” originating from water-thickened interlobular septa. These images could be useful for noninvasive assessment of interstitial pulmonary edema.

Study objective

The purpose of this study was to assess the diagnostic accuracy of lung comet-tail images compared with chest radiography, wedge pressure, and extravascular lung water (EVLW) quantified by the indicator dilution method (PiCCO System, version 4.1; Pulsion Medical Systems; Munich, Germany).

Methods and patients

We enrolled 20 patients (mean age, 62.6 ± 11.5 years [± SD]). Patients were studied before, immediately after, and 24 h following cardiac surgery with chest ultrasound, chest radiography, pulmonary artery catheterization, and the PiCCO system. Performing echo scanning (right and left hemithorax, from second to fourth intercostal space, from parasternal to midaxillary line), an individual patient comet score was obtained by summing the number of comets in each scanned space.

Results

A total of 60 comparisons were obtained. Significant positive linear correlations were found between comet score and EVLW determined by the PiCCO System (r = 0.42, p = 0.001), between comet score and wedge pressure (r = 0.48, p = 0.01), and between comet score and radiologic lung water score (r = 0.60, p = 0.0001).

Conclusions

The presence and the number of comet-tail images provide reliable information on interstitial pulmonary edema. Therefore, ultrasonography represent an attractive, easy-to-use, bedside diagnostic tool for assessing cardiac function and pulmonary congestion.

Section snippets

Patients

We enrolled 20 patients (16 men and 4 women; mean age, 62.6 ± 11.5 years) who underwent cardiac surgery with cardiopulmonary bypass (Table 1). Patients with lung diseases were excluded. The patients were assessed with chest ultrasonography, chest radiography, pulmonary artery catheterization, and the PiCCO System at baseline, immediately after surgical operation, and after 24 h. All examinations were performed within a few minutes and were read by independent operators unaware of the results of

Results

The determinations with the different methods were obtained in all patients. No data were rejected. A total of 60 comparative measurements were performed between the methods.

Discussion

The present study shows that the lung comet-tail images are correlated with wedge pressure and EVLW. Thus, their presence and number permit quantification of the excess of EVLW, providing an indirect measurement of wedge pressure. Moreover, it is sufficiently sensitive and accurate to detect pulmonary interstitial edema even before it becomes apparent clinically.

The comet-tail images appear when there is a marked difference in acoustic impedance between an object and its surroundings.4 The

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