title: The oxygenation variations related to prone positioning during mechanical ventilation: a clinical comparison between ARDS and non-ARDS hypoxemic patients.
abstract: OBJECTIVE
  To compare, in clinical practice, the oxygenation variations related to prone positioning (PP) during mechanical ventilation in ARDS and non-ARDS hypoxemic patients.
  
  
  METHODS
  Prospective observational study of data on consecutive patients treated with the same protocol in the intensive care unit (ICU) of a university hospital.
  
  
  METHODS
  From May 1996 to December 1998, 226 PP periods without adjunction of nitric oxide (NO) inhalation and/or almitrine bismesylate infusion, performed in 59 mechanically ventilated hypoxemic patients (arterial oxygen tension/fractional inspired oxygen (PaO2/FIO2) ratio <300 mmHg) with no evidence of left ventricular failure, were included in this study.
  
  
  METHODS
  Arterial blood gas was measured before the PP, at 1 h from the beginning of the PP, at the end of the PP and 1 h after returning to the supine position.
  
  
  RESULTS
  We analyzed 136 PP periods in 34 non-ARDS patients (60.2%) and 90 in 25 ARDS patients. The PP was repeated and the duration of the PP periods was: 10.6+/-0.22 h. The PP during the mechanical ventilation appeared to be safe and well tolerated. A PaO2/FIO2 ratio improvement at the end of the PP period, occurred for 196 periods (86.7%) with a mean PaO2/FIO2 ratio increase of +46.4+/-0.03% at the end of the PP periods compared to the baseline supine value. The PaO2/FIO2 ratio variations at 1 h after the start of the PP, at the end of the PP period and at 1 h after the return to supine were not different in ARDS or non-ARDS hypoxemic patients. The PaO2/FIO2 ratio improvement appeared to be more intense and more rapid in ARDS patients.
  
  
  CONCLUSIONS
  In about 90% of periods, PP improved the PaO2/FIO2 ratio in patients with ARDS as well as in hypoxemic patients with non-ARDS. Studies are necessary to determine the impact of PP on survival and the mechanical ventilation duration in ARDS or non-ARDS hypoxemic patients.
authors.affiliation: Service de Réanimation Polyvalente, CHRU Saint Etienne, Hopital Bellevue, 42055 Saint Etienne Cedex 2, France.
authors.forename: C
authors.initials: C
authors.lastname: Venet
authors.forename: S
authors.initials: S
authors.lastname: Guyomarc'h
authors.forename: C
authors.initials: C
authors.lastname: Migeot
authors.forename: M
authors.initials: M
authors.lastname: Bertrand
authors.forename: P
authors.initials: P
authors.lastname: Gery
authors.forename: D
authors.initials: D
authors.lastname: Page
authors.forename: R
authors.initials: R
authors.lastname: Vermesch
authors.forename: J C
authors.initials: JC
authors.lastname: Bertrand
authors.forename: F
authors.initials: F
authors.lastname: Zeni
mesh_terms: D000704:Analysis of Variance; D006801:Humans; D000860:Hypoxia / Q000628:therapy*; D010100:Oxygen / Q000378:metabolism; D011175:Positive-Pressure Respiration / Q000379:methods*; D016684:Prone Position; D011446:Prospective Studies; D012128:Respiratory Distress Syndrome / Q000628:therapy*; D018709:Statistics, Nonparametric; D016683:Supine Position
chemical_list: D010100:Oxygen