title: Recruitment maneuvers during prone positioning in patients with acute respiratory distress syndrome.
abstract: OBJECTIVE
  To evaluate the interaction of recruitment maneuvers and prone positioning on gas exchange and venous admixture in patients with early extrapulmonary acute respiratory distress syndrome ventilated with high levels of positive end-expiratory pressure. We hypothesized that a sustained inflation performed after 6 hrs of prone positioning would induce sustained improvement in oxygenation (Pao2/Fio2) and venous admixture.
  
  
  METHODS
  Prospective, interventional study.
  
  
  METHODS
  Tertiary care, postoperative intensive care unit.
  
  
  METHODS
  Fifteen patients with early extrapulmonary acute respiratory distress syndrome.
  
  
  METHODS
  After 6 hrs of prone positioning, a sustained inflation was performed with 50 cm H2O maintained for 30 secs. Data were recorded in supine position, after 6 hrs of prone positioning, at 3, 30, and 180 mins following the sustained inflation.
  
  
  RESULTS
  A response to prone positioning was observed in nine of 15 patients leading to an improvement of Pao2/Fio2 (147 +/- 37 torr vs. 225 +/- 77 torr, p = .005) and venous admixture (35.4 +/- 8.3% vs. 28.9 +/- 9.8%, p = .001). Six patients did not respond to prone positioning. Following the sustained inflation, the responders to prone positioning showed a further increase of Pao2/Fio2 and decrease of venous admixture at 3 mins (Pao2/Fio2, 225 +/- 77 torr vs. 368 +/- 90 torr, p = .018; venous admixture, 28.9 +/- 9.8% vs. 18.9 +/- 6.7%, p = .05). In all six nonresponders to prone positioning, an improvement of Pao2/Fio2 and venous admixture occurred at 3 mins following the sustained inflation (128 +/- 18 torr vs. 277 +/- 59 torr, p = .03; venous admixture, 34.2 +/- 6.0% vs. 23.8 +/- 6.3%, p = .05). The beneficial effects of the sustained inflation remained significantly elevated over 3 hrs in responders and nonresponders to prone positioning.
  
  
  CONCLUSIONS
  In patients with early extrapulmonary acute respiratory distress syndrome, a sustained inflation performed after 6 hrs of prone positioning induced further and sustained improvement of oxygenation and venous admixture in both responders and nonresponders to prone positioning.
authors.affiliation: Department of Anesthesia and Intensive Care and the Ludwig Boltzmann Institute for Economics of Medicine in Anesthesia and Intensive Care, City of Vienna Hospital-Lainz, Vienna, Austria.
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Oczenski
authors.forename: Christoph
authors.initials: C
authors.lastname: Hörmann
authors.forename: Christian
authors.initials: C
authors.lastname: Keller
authors.forename: Norbert
authors.initials: N
authors.lastname: Lorenzl
authors.forename: Anton
authors.initials: A
authors.lastname: Kepka
authors.forename: Sylvia
authors.initials: S
authors.lastname: Schwarz
authors.forename: Robert D
authors.initials: RD
authors.lastname: Fitzgerald
mesh_terms: D000328:Adult; D000368:Aged; D000403:Airway Resistance / Q000502:physiology; D003422:Critical Care / Q000379:methods*; D005260:Female; D006801:Humans; D006874:Hydrostatic Pressure; D008170:Lung Compliance / Q000502:physiology; D008297:Male; D008875:Middle Aged; D010100:Oxygen / Q000097:blood*; D011175:Positive-Pressure Respiration / Q000379:methods*; D016684:Prone Position / Q000502:physiology*; D011446:Prospective Studies; D011650:Pulmonary Alveoli / Q000503:physiopathology; D011659:Pulmonary Gas Exchange / Q000502:physiology*; D012128:Respiratory Distress Syndrome / Q000503:physiopathology / Q000628:therapy*; D016896:Treatment Outcome
chemical_list: D010100:Oxygen