title: The clinical usefulness of extravascular lung water and pulmonary vascular permeability index to diagnose and characterize pulmonary edema: a prospective multicenter study on the quantitative differential diagnostic definition for acute lung injury/acute respiratory distress syndrome.
abstract: BACKGROUND
  Acute lung injury (ALI)/acute respiratory distress syndrome (ARDS) is characterized by features other than increased pulmonary vascular permeability. Pulmonary vascular permeability combined with increased extravascular lung water content has been considered a quantitative diagnostic criterion of ALI/ARDS. This prospective, multi-institutional, observational study aimed to clarify the clinical pathophysiological features of ALI/ARDS and establish its quantitative diagnostic criteria.
  
  
  METHODS
  The extravascular lung water index (EVLWI) and the pulmonary vascular permeability index (PVPI) were measured using the transpulmonary thermodilution method in 266 patients with PaO2/FiO2 ratio ≤ 300 mmHg and bilateral infiltration on chest radiography, in 23 ICUs of academic tertiary referral hospitals. Pulmonary edema was defined as EVLWI ≥ 10 ml/kg. Three experts retrospectively determined the pathophysiological features of respiratory insufficiency by considering the patients' history, clinical presentation, chest computed tomography and radiography, echocardiography, EVLWI and brain natriuretic peptide level, and the time course of all preceding findings under systemic and respiratory therapy.
  
  
  RESULTS
  Patients were divided into the following three categories on the basis of the pathophysiological diagnostic differentiation of respiratory insufficiency: ALI/ARDS, cardiogenic edema, and pleural effusion with atelectasis, which were noted in 207 patients, 26 patients, and 33 patients, respectively. EVLWI was greater in ALI/ARDS and cardiogenic edema patients than in patients with pleural effusion with atelectasis (18.5 ± 6.8, 14.4 ± 4.0, and 8.3 ± 2.1, respectively; P < 0.01). PVPI was higher in ALI/ARDS patients than in cardiogenic edema or pleural effusion with atelectasis patients (3.2 ± 1.4, 2.0 ± 0.8, and 1.6 ± 0.5; P < 0.01). In ALI/ARDS patients, EVLWI increased with increasing pulmonary vascular permeability (r = 0.729, P < 0.01) and was weakly correlated with intrathoracic blood volume (r = 0.236, P < 0.01). EVLWI was weakly correlated with the PaO2/FiO2 ratio in the ALI/ARDS and cardiogenic edema patients. A PVPI value of 2.6 to 2.85 provided a definitive diagnosis of ALI/ARDS (specificity, 0.90 to 0.95), and a value < 1.7 ruled out an ALI/ARDS diagnosis (specificity, 0.95).
  
  
  CONCLUSIONS
  PVPI may be a useful quantitative diagnostic tool for ARDS in patients with hypoxemic respiratory failure and radiographic infiltrates.
  
  
  BACKGROUND
  UMIN-CTR ID UMIN000003627.
authors.forename: Shigeki
authors.initials: S
authors.lastname: Kushimoto
authors.forename: Yasuhiko
authors.initials: Y
authors.lastname: Taira
authors.forename: Yasuhide
authors.initials: Y
authors.lastname: Kitazawa
authors.forename: Kazuo
authors.initials: K
authors.lastname: Okuchi
authors.forename: Teruo
authors.initials: T
authors.lastname: Sakamoto
authors.forename: Hiroyasu
authors.initials: H
authors.lastname: Ishikura
authors.forename: Tomoyuki
authors.initials: T
authors.lastname: Endo
authors.forename: Satoshi
authors.initials: S
authors.lastname: Yamanouchi
authors.forename: Takashi
authors.initials: T
authors.lastname: Tagami
authors.forename: Junko
authors.initials: J
authors.lastname: Yamaguchi
authors.forename: Kazuhide
authors.initials: K
authors.lastname: Yoshikawa
authors.forename: Manabu
authors.initials: M
authors.lastname: Sugita
authors.forename: Yoichi
authors.initials: Y
authors.lastname: Kase
authors.forename: Takashi
authors.initials: T
authors.lastname: Kanemura
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Takahashi
authors.forename: Yuichi
authors.initials: Y
authors.lastname: Kuroki
authors.forename: Hiroo
authors.initials: H
authors.lastname: Izumino
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Rinka
authors.forename: Ryutarou
authors.initials: R
authors.lastname: Seo
authors.forename: Makoto
authors.initials: M
authors.lastname: Takatori
authors.forename: Tadashi
authors.initials: T
authors.lastname: Kaneko
authors.forename: Toshiaki
authors.initials: T
authors.lastname: Nakamura
authors.forename: Takayuki
authors.initials: T
authors.lastname: Irahara
authors.forename: Nobuyuki
authors.initials: N
authors.lastname: Saito
authors.forename: Akihiro
authors.initials: A
authors.lastname: Watanabe
mesh_terms: D055371:Acute Lung Injury / Q000175:diagnosis*; D000368:Aged; D002199:Capillary Permeability / Q000502:physiology*; D003937:Diagnosis, Differential; D015633:Extravascular Lung Water / Q000502:physiology*; D005260:Female; D006801:Humans; D008168:Lung / Q000098:blood supply / Q000503:physiopathology*; D008297:Male; D011446:Prospective Studies; D011654:Pulmonary Edema / Q000175:diagnosis*; D012128:Respiratory Distress Syndrome / Q000175:diagnosis*; D013815:Thermodilution / Q000379:methods