Chest Xray - Vascular Pedical Width

5/8/02 (Difrancesco)

Question: What is vascular pedicle width, and how is it used to evaluate a chest xray for intravascular volume status?

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Unique Identifier:11888980

Authors: Ely EW. Haponik EF.

Institution: Department of Medicine the Vanderbilt University School of Medicine, Nashville, TN 37232-8300, USA. wes.ely@mcmail.vanderbilt.edu

Title: Using the chest radiograph to determine intravascular volume status: the role of vascular pedicle width.

Source: Chest. 121(3):942-50, 2002 Mar.

Abstract: Due to concerns about the efficacy and safety of using pulmonary artery catheterization to evaluate hemodynamic status, noninvasive diagnostic testing has gained increased importance. This article focuses on both the supportive evidence and the limitations of applying the vascular pedicle width (VPW), which is the mediastinal silhouette of the great vessels, as an aid in the assessment of patients' intravascular volume status. The objective measurement of the VPW obtained from either upright or supine chest radiographs (CXRs which are often already available though not fully utilized) can increase the accuracy of the clinical and radiographic assessment of intravascular volume status by 15 to 30%, and this value may be even higher when VPW is used serially within the same patient. Regardless of the presence or absence of pulmonary edema, the best VPW cutoff for differentiating a high vs normal to low intravascular volume status is 70 mm. Patients with a VPW of > 70 mm coupled with a cardiothoracic ratio of > 0.55 are more than three times more likely to have a pulmonary artery occlusion pressure > 18 mm Hg than are patients without these radiographic findings. We suggest a management algorithm for utilizing the VPW, and whether or not such an approach will offer superior patient outcomes requires prospective investigation. Reappraisal of the VPW and other roentgenographic signs should be incorporated into newly implemented studies of the Swan-Ganz catheter, ICU echocardiography, portable CT scans, and other costlier technologies. While such investigations may refine the optimum application of the portable CXR, conventional and digital supine radiographs should retain an important role in the diagnosis and management of critically ill patients. Lastly, the measurement of the VPW should be incorporated into the training of chest clinicians and radiologists.

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Unique Identifier:3872571

Authors: Milne EN. Pistolesi M. Miniati M. Giuntini C.

Title: The radiologic distinction of cardiogenic and noncardiogenic edema.

Source: AJR. American Journal of Roentgenology. 144(5):879-94, 1985 May.

Abstract: Improvement in the ability to determine the specific cause of any given case of pulmonary edema would lead to more rapid and definitive treatment. "Wedge" pressures and measurements of cardiac output derived from Swan-Ganz catheterization assist in making this determination, but the procedure is invasive, expensive, associated with complications, and not infrequently inaccurate. A plain chest film is, however, almost invariably available in all patients with pulmonary edema, and as shown in this study, the cause of the edema can be determined with a high degree of accuracy by careful attention to certain radiographic features. An independent two-observer study was performed on 216 chest radiographs of 61 patients with cardiac disease, 30 with renal failure or overhydration, and 28 with capillary permeability edema. Three principal and seven ancillary features have been identified, all of which are statistically significant and permit the cause of the edema to be determined correctly in a high percentage of cases. The three principal features are distribution of pulmonary flow, distribution of pulmonary edema, and the width of the vascular pedicle. The ancillary features are pulmonary blood volume, peribronchial cuffing, septal lines, pleural effusions, air bronchograms, lung volume, and cardiac size. Differing constellations of these features occur, each of which is characteristic of a specific type of edema. Overall accuracy of diagnosis in this study ranged from 86% to 89%. The highest accuracy was obtained in distinguishing capillary permeability edema from all other varieties (91%), and the lowest in distinguishing chronic cardiac failure from renal failure (81%).