title: Differentiation of cardiac and noncardiac dyspnea using bioelectrical impedance vector analysis (BIVA).
abstract: BACKGROUND
  There is no gold standard for the differential diagnosis of acute dyspnea despite the usefulness of N-terminal pro-B-type natriuretic peptide (NT-proBNP) and lung ultrasound. No study has evaluated the contribution of bioelectrical impedance vector analysis (BIVA) in discriminating between cardiac and noncardiac dyspnea. We sought to determine whether a relationship exists between ultrasound detection of lung congestion, NT-proBNP, and BIVA in patients with acute dyspnea.
  
  
  RESULTS
  Eligible patients were between 50 and 95 years, with an estimated glomerular filtration rate of ≥30 mL min(-1) 1.73 m(-2), who presented to an emergency department with dyspnea. Dyspnea was classified by reviewers blinded to BIVA as cardiac or noncardiac based on physical examination, electrocardiogram, chest X-ray, NT-proBNP, and B-lines of lung congestion on ultrasound. Overall, 315 patients were enrolled (median age 77 years, 48% male). An adjudicated diagnosis of cardiac dyspnea was established in 169 (54%). Using BIVA, vector positions below -1 SD of the Z-score of reactance were associated with peripheral congestion (χ(2) = 115; P < .001). BIVA measures were reasonably accurate in discriminating cardiac and noncardiac dyspnea (69% sensitivity, 79% specificity, 80% area under the receiver operating characteristic curve).
  
  
  CONCLUSIONS
  In patients presenting with acute dyspnea, the combination of BIVA and lung ultrasound may provide a rapid noninvasive method to determine the cause of dyspnea.
authors.affiliation: Department of Medicine, University of Padova, Padova, Italy. apiccoli@unipd.it
authors.forename: Antonio
authors.initials: A
authors.lastname: Piccoli
authors.forename: Marta
authors.initials: M
authors.lastname: Codognotto
authors.forename: Vito
authors.initials: V
authors.lastname: Cianci
authors.forename: Gianna
authors.initials: G
authors.lastname: Vettore
authors.forename: Martina
authors.initials: M
authors.lastname: Zaninotto
authors.forename: Mario
authors.initials: M
authors.lastname: Plebani
authors.forename: Alan
authors.initials: A
authors.lastname: Maisel
authors.forename: W Frank
authors.initials: WF
authors.lastname: Peacock
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D003430:Cross-Sectional Studies; D003937:Diagnosis, Differential; D004417:Dyspnea / Q000097:blood / Q000000981:diagnostic imaging* / Q000503:physiopathology; D017097:Electric Impedance; D005260:Female; D006801:Humans; D008171:Lung Diseases / Q000097:blood / Q000000981:diagnostic imaging* / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D020097:Natriuretic Peptide, Brain / Q000097:blood; D010446:Peptide Fragments / Q000097:blood; D011446:Prospective Studies; D014463:Ultrasonography
chemical_list: D010446:Peptide Fragments; C109794:pro-brain natriuretic peptide (1-76); D020097:Natriuretic Peptide, Brain