title: A prospective cohort study of ALI/ARDS in the Tohoku district of Japan (second report).
abstract: OBJECTIVE
  We previously reported a study of systemic inflammatory response syndrome (SIRS) cases in the Tohoku district of Japan in which the patients showed a 30-day mortality from acute lung injury/acute respiratory distress syndrome (ALI/ARDS) of about 20%. Cases in which chest X-ray findings did not meet ALI/ARDS criteria were diagnosed as acute hypoxemic respiratory failure (AHRF), but about 50% of these patients progressed to ALI/ARDS. The objective of this study was to verify the findings obtained in the earlier study and to gain further insights into the pathognomonic symptoms of AHRF associated with SIRS.
  
  
  METHODS
  A prospective cohort study was performed in SIRS patients admitted to the intensive care unit (ICU) with PaO(2)/fractional inspired oxygen (FIO(2)) < or = 300 mmHg. Patients were assigned to ALI or ARDS groups based on symptoms at ICU entry. Cases in which chest X-ray showed no infiltration shadows in bilateral lung fields were classified as AHRF.
  
  
  RESULTS
  A total of 240 patients were enrolled in the study. The 30-day mortalities were 21.6% and 20.0% in the ALI and ARDS groups, respectively. Of the 88 AHRF patients, 49 progressed to ALI/ARDS, with progression occurring within 3 days after ICU entry in most cases; 39 patients recovered with no progression. Chest X-ray and computed tomography (CT) showed no findings indicating ALI/ARDS in 20 AHRF patients at ICU entry, but 7 of these patients progressed to ALI/ARDS.
  
  
  CONCLUSIONS
  The mortality rates of ALI and ARDS were 21.6% and 20.5%, respectively. More than half of the AHRF patients progressed to ALI or ARDS. Some AHRF patients had normal findings on chest CT, but subsequently showed a bilateral shadow on a chest X-ray. This indicates that mild pathologic lesions may not show imaging abnormalities.
authors.affiliation: Department of Critical Care Medicine, Iwate Medical University, 19-1 Uchimaru, Morioka, 020-8505, Japan. sendo@iwate-med.ac.jp
authors.forename: Shigeatsu
authors.initials: S
authors.lastname: Endo
authors.forename: Shigehiro
authors.initials: S
authors.lastname: Shibata
authors.forename: Nobuhiro
authors.initials: N
authors.lastname: Sato
authors.forename: Eiji
authors.initials: E
authors.lastname: Hashiba
authors.forename: Kimitaka
authors.initials: K
authors.lastname: Tajimi
authors.forename: Koji
authors.initials: K
authors.lastname: Saito
authors.forename: Kaneyuki
authors.initials: K
authors.lastname: Kawamae
authors.forename: Masaki
authors.initials: M
authors.lastname: Nakane
authors.forename: Masahiro
authors.initials: M
authors.lastname: Murakawa
mesh_terms: D018806:APACHE; D055371:Acute Lung Injury / Q000175:diagnosis / Q000453:epidemiology / Q000401:mortality*; D000368:Aged; D015331:Cohort Studies; D003422:Critical Care; D018450:Disease Progression; D005260:Female; D006801:Humans; D000860:Hypoxia / Q000401:mortality; D007564:Japan / Q000453:epidemiology; D008168:Lung / Q000378:metabolism; D008297:Male; D008875:Middle Aged; D010101:Oxygen Consumption; D011446:Prospective Studies; D013902:Radiography, Thoracic; D012128:Respiratory Distress Syndrome / Q000175:diagnosis / Q000453:epidemiology / Q000401:mortality*; D012129:Respiratory Function Tests; D018746:Systemic Inflammatory Response Syndrome / Q000175:diagnosis / Q000453:epidemiology / Q000401:mortality*