title: Effect of inspired oxygen fraction on alveolar derecruitment in acute respiratory distress syndrome.
abstract: OBJECTIVE
  High fractions of inspired oxygen (FIO(2)) used in acute lung injury (ALI) may promote resorption atelectasis. The impact of derecruitment related to high FIO(2) in ALI is debated. We evaluated derecruitment with 100% vs. 60% FIO(2) at two levels of positive end-expiratory pressure (PEEP).
  
  
  METHODS
  Fourteen consecutive patients with ALI were studied.
  
  
  METHODS
  Recruited volume at two PEEP levels was computed from two pressure-volume curves, recorded from PEEP and from zero end-expiratory pressure, using the sinusoidal flow modulation method. PEEP-induced recruitment was measured during prolonged expiration as the difference between the two curves at a given pressure. PaO(2)/FIO(2) was also measured. PEEP was 5 +/- 1 or 14 +/- 3 cmH(2)O and FIO(2) was 60% or 100%, yielding four combinations. We looked for differences between the beginning and end of a 30-min period with each combination.
  
  
  RESULTS
  With low PEEP and 100% FIO(2), recruited volume decreased significantly from 68 +/- 53 to 39 +/- 43 ml and PaO(2)/FIO(2) from 196 +/- 104 to 153 +/- 83 mmHg. With the three other combinations (low PEEP and 60% FIO(2) or high PEEP and 60% or 100% FIO(2)) none of the parameters decreased significantly.
  
  
  CONCLUSIONS
  In mechanically ventilated patients with ALI the breathing of pure oxygen leads to derecruitment, which is prevented by high PEEP.
authors.affiliation: Service de Réanimation Médicale de L'hôpital Henri Mondor, AP-HP, 51, av du Maréchal de Lattre de Tassigny, Créteil, France.
authors.forename: Jérôme
authors.initials: J
authors.lastname: Aboab
authors.forename: Bjorn
authors.initials: B
authors.lastname: Jonson
authors.forename: Achille
authors.initials: A
authors.lastname: Kouatchet
authors.forename: Solenne
authors.initials: S
authors.lastname: Taille
authors.forename: Lisbet
authors.initials: L
authors.lastname: Niklason
authors.forename: Laurent
authors.initials: L
authors.lastname: Brochard
mesh_terms: D000328:Adult; D000368:Aged; D006801:Humans; D008875:Middle Aged; D010100:Oxygen / Q000008:administration & dosage / Q000009:adverse effects*; D011175:Positive-Pressure Respiration / Q000009:adverse effects* / Q000379:methods; D001261:Pulmonary Atelectasis / Q000139:chemically induced*; D011659:Pulmonary Gas Exchange; D012128:Respiratory Distress Syndrome / Q000628:therapy*; D013990:Tidal Volume
chemical_list: D010100:Oxygen