title: B-type natriuretic peptide in the assessment of acute lung injury and cardiogenic pulmonary edema.
abstract: OBJECTIVE
  The role of plasma B-type natriuretic peptide (BNP) in critically ill patients with acute pulmonary edema is controversial. We postulated that a low BNP level would exclude cardiac dysfunction as the principal cause of pulmonary edema and therefore help in the diagnosis of acute lung injury.
  
  
  METHODS
  A retrospective derivation cohort was followed by a prospective validation cohort of consecutive patients with acute pulmonary edema admitted to three intensive care units. BNP was measured within 24 hrs from onset. Critical care experts blinded to BNP results integrated clinical data with the course of disease and response to therapy and served as the reference standard.
  
  
  METHODS
  Three intensive care units at the tertiary center.
  
  
  METHODS
  Consecutive critically ill patients with acute pulmonary edema.
  
  
  METHODS
  None.
  
  
  RESULTS
  In a derivation cohort of 84 patients, a BNP threshold of <or=250 pg/mL had a specificity of 87% and sensitivity of 48% for the diagnosis of acute lung injury. High specificity of BNP (90%, likelihood ratio of 3.9) was confirmed in a validation cohort of 120 consecutive patients, 52 (43%) of whom had acute lung injury. Notably, 32% of patients with acute lung injury had concomitant cardiac dysfunction. The median time from the onset of pulmonary edema to BNP testing was 3 hrs. The accuracy of BNP (area under receiver operator curve, 0.71) was comparable with pulmonary artery occlusion pressure (area under receiver operator curve, 0.66) and superior to ejection fraction (area under receiver operator curve, 0.60) in subgroups of patients in whom these tests were performed. The accuracy of BNP improved when patients with renal insufficiency were excluded (area under receiver operator curve, 0.82).
  
  
  CONCLUSIONS
  When measured early after the onset of acute pulmonary edema, a BNP level of <250 pg/mL supports the diagnosis of acute lung injury. The high rate of cardiac and renal dysfunction in critically ill patients limits the discriminative role of BNP. No level of BNP could completely exclude cardiac dysfunction.
authors.affiliation: Department of Internal Medicine, Division of Pulmonary and Critical Care Medicine, Mayo Clinic College of Medicine, Rochester, MN, USA.
authors.forename: Rimki
authors.initials: R
authors.lastname: Rana
authors.forename: Nicholas E
authors.initials: NE
authors.lastname: Vlahakis
authors.forename: Craig E
authors.initials: CE
authors.lastname: Daniels
authors.forename: Allan S
authors.initials: AS
authors.lastname: Jaffe
authors.forename: George G
authors.initials: GG
authors.lastname: Klee
authors.forename: Rolf D
authors.initials: RD
authors.lastname: Hubmayr
authors.forename: Ognjen
authors.initials: O
authors.lastname: Gajic
mesh_terms: D000208:Acute Disease; D000368:Aged; D000369:Aged, 80 and over; D015415:Biomarkers / Q000097:blood; D016638:Critical Illness; D003937:Diagnosis, Differential; D005260:Female; D006331:Heart Diseases / Q000150:complications* / Q000175:diagnosis*; D006801:Humans; D008171:Lung Diseases / Q000175:diagnosis*; D008297:Male; D020097:Natriuretic Peptide, Brain / Q000097:blood*; D011446:Prospective Studies; D011654:Pulmonary Edema / Q000175:diagnosis / Q000209:etiology*; D012189:Retrospective Studies; D012680:Sensitivity and Specificity
chemical_list: D015415:Biomarkers; D020097:Natriuretic Peptide, Brain