title: Influence of direct and indirect etiology on acute outcome and 6-month functional recovery in acute respiratory distress syndrome.
abstract: OBJECTIVE
  To assess the possibility that acute respiratory distress syndrome (ARDS) of pulmonary and nonpulmonary origins represent two distinct syndromes.
  
  
  METHODS
  Analysis of data collected prospectively from an inception cohort of 117 patients with ARDS.
  
  
  METHODS
  Adult intensive care unit (ICU), university/postgraduate hospital.
  
  
  RESULTS
  Differences were sought in mortality and 6-month functional outcome between patients developing ARDS due to pulmonary (group 1) and nonpulmonary (group 2) pathology. Group 1 patients displayed a trend toward increased ICU and in-hospital mortality (42.1% vs. 23.2%, p = .10, and 47.4% vs. 27.9%, p = .11, respectively). No difference was found in ICU length of stay (46.3 +/- 4.9 vs. 39.0 +/- 4.8 days for groups 1 and 2, respectively) nor in duration of positive-pressure ventilation (26.2 +/- 4.3 vs. 20.6 +/- 3.2 days). However, the need for pressure-controlled inverse ratio ventilation was significantly greater in group 1 (16.9 +/- 3.2 vs. 9.1 +/- 1.3 days; p = .033). In survivors, reductions in total lung capacity at 6 months (68.1 +/- 4.6 vs. 61.8 +/- 4.6% predicted for groups 1 and 2, respectively; p = .4), accessible lung volume (74.4 +/- 4.4 vs. 68.9 +/- 4.9% predicted; p = .56), and forced expiratory volume (77.8 +/- 2.9 vs. 80.3 +/- 2.4% predicted; p = .57) did not differ between groups. Gas transfer coefficient was well preserved (84.5 +/- 4.6 vs. 86.6 +/- 4.7% predicted; p = .80).
  
  
  CONCLUSIONS
  These data suggest a trend toward higher mortality and ventilatory requirements in ARDS of direct etiology, generating a hypothesis worthy of further exploration.
authors.affiliation: Unit of Critical Care, Imperial College School of Medicine, Royal Brompton Hospital, London, United Kingdom.
authors.forename: G
authors.initials: G
authors.lastname: Suntharalingam
authors.forename: K
authors.initials: K
authors.lastname: Regan
authors.forename: B F
authors.initials: BF
authors.lastname: Keogh
authors.forename: C J
authors.initials: CJ
authors.lastname: Morgan
authors.forename: T W
authors.initials: TW
authors.lastname: Evans
mesh_terms: D018806:APACHE; D000328:Adult; D003422:Critical Care; D005260:Female; D017052:Hospital Mortality; D006801:Humans; D007902:Length of Stay / Q000706:statistics & numerical data; D008176:Lung Volume Measurements; D008297:Male; D008875:Middle Aged; D011175:Positive-Pressure Respiration / Q000379:methods; D011237:Predictive Value of Tests; D011379:Prognosis; D011446:Prospective Studies; D020127:Recovery of Function; D012128:Respiratory Distress Syndrome / Q000209:etiology* / Q000401:mortality / Q000503:physiopathology* / Q000628:therapy; D018709:Statistics, Nonparametric; D016019:Survival Analysis; D013997:Time Factors; D016896:Treatment Outcome