title: Potential effects of corticosteroids on physiological dead-space fraction in acute respiratory distress syndrome.
abstract: BACKGROUND
  Increased dead-space fraction is common in patients with persistent acute respiratory distress syndrome (ARDS). We evaluated the changes in the oxygenation and dead-space fraction in patients with persistent ARDS after corticosteroid therapy.
  
  
  METHODS
  This was a non-randomized  non-placebo, controlled observational study including 19 patients with persistent ARDS treated with corticosteroids. We measured P(aO(2))/F(IO(2)) and dead-space fraction at days 0, 4, and 7 after corticosteroids treatment (methylprednisolone) initiation.  Patients were classified in intermediate group when corticosteroids were initiated between days 8-14 after ARDS onset, and in late group when initiated after 14 days.
  
  
  RESULTS
  Mean time from the diagnosis of the ARDS to methylprednisolone treatment was 11 ± 2 days in the intermediate  group (10 patients) and 21 ± 8 days in the late group (9 patients). When comparing days 0, 4, and 7 after methylprednisolone treatment, we found an increase in the P(aO(2))/F(IO(2)) (145 ± 64 mm Hg, 190 ± 68 mm Hg, and 226 ± 84  mm Hg, respectively, P < .001) and a decrease in the physiological dead-space fraction (0.66 ± 0.10, 0.58 ± 0.12, and 0.53 ± 0.11, respectively, P < .001). No differences were found between the intermediate and late groups.
  
  
  CONCLUSIONS
  In patients  with persistent ARDS, the increase in oxygenation was accompanied by a decrease in the dead-space fraction after a few days of corticosteroid treatment. To confirm potential benefit of corticosteroids on physiological parameters and mortality will require a powered randomized placebo controlled  trial.
authors: Hospital Universitari Son Espases, Palma de Mallorca, Illes Balears, Spain. joan.raurich@ssib.es
authors: Joan M
authors: JM
authors: Raurich
authors: Mireia
authors: M
authors: Ferreruela
authors: Juan A
authors: JA
authors: Llompart-Pou
authors: Margalida
authors: M
authors: Vilar
authors: Asunción
authors: A
authors: Colomar
authors: Ignacio
authors: I
authors: Ayestarán
authors: Jon
authors: J
authors: Pérez-Bárcena
authors: Jordi
authors: J
authors: Ibáñez
mesh_terms: D000328:Adult; D005260:Female; D005938:Glucocorticoids / Q000494:pharmacology* / Q000627:therapeutic use; D006801:Humans; D008297:Male; D008775:Methylprednisolone / Q000494:pharmacology* / Q000627:therapeutic use; D008875:Middle Aged; D012121:Respiration, Artificial; D012126:Respiratory Dead Space / Q000187:drug effects* / Q000502:physiology*; D012128:Respiratory Distress Syndrome / Q000188:drug therapy* / Q000503:physiopathology*; D012129:Respiratory Function Tests; D013990:Tidal Volume / Q000502:physiology; D013997:Time Factors
chemical_list: D005938:Glucocorticoids; D008775:Methylprednisolone