title: Prolonged moderate pressure recruitment manoeuvre results in lower optimal positive end-expiratory pressure and plateau pressure.
abstract: BACKGROUND
  In acute lung injury (ALI)/acute respiratory distress syndrome (ARDS), recruitment manoeuvres (RMs) are used frequently. In pigs with induced ALI, superior effects have been found using a slow moderate-pressure recruitment manoeuvre (SLRM) compared with a vital capacity recruitment manoeuvre (VICM). We hypothesized that the positive recruitment effects of SLRM could also be achieved in ALI/ARDS patients. Our primary research question was whether the same compliance could be obtained using lower RM pressure and subsequent positive end-expiratory pressure (PEEP). Secondly, optimal PEEP levels following the RMs were compared, and the use of volume-dependent compliance (VDC) to identify successful lung recruitment and optimal PEEP was evaluated.
  
  
  METHODS
  We performed a prospective randomised cross-over study where 16 ventilated patients with early ALI/ARDS each were subjected to the two RMs, followed by decremental PEEP titration. Volume-dependent initial, middle and final compliance (C(ini) , C(mid) and C(fin) ) were determined. Electric impedance tomography and end-expiratory lung volume measurements were used to follow lung volume changes.
  
  
  RESULTS
  The maximum response in compliance, PaO₂/FIO₂, venous admixture and C(ini) /C(fin) after recruitment, during decremental PEEP, was at significantly lower PEEP and plateau pressure after SLRM than VICM. Fewer patients responded in gas exchange after the SLRM, which was not the case for lung mechanics. The response in C(ini) was more pronounced than in conventional compliance.
  
  
  CONCLUSIONS
  The same compliance increase is achieved with SLRM as with VICM, and lower PEEP can be used, with correspondingly lower plateau pressures. VDC seems promising to identify successful recruitment and optimal PEEP.
authors.affiliation: Department of Anaesthesia and Intensive Care Medicine, Sahlgrenska University Hospital, Gothenburg, Sweden. karin.lowhagen@vgregion.se
authors.forename: K
authors.initials: K
authors.lastname: Lowhagen
authors.forename: S
authors.initials: S
authors.lastname: Lindgren
authors.forename: H
authors.initials: H
authors.lastname: Odenstedt
authors.forename: O
authors.initials: O
authors.lastname: Stenqvist
authors.forename: S
authors.initials: S
authors.lastname: Lundin
mesh_terms: D055371:Acute Lung Injury / Q000503:physiopathology / Q000628:therapy*; D000368:Aged; D018686:Anesthetics, Intravenous / Q000494:pharmacology; D002302:Cardiac Output / Q000502:physiology; D018592:Cross-Over Studies; D017097:Electric Impedance; D005260:Female; D005283:Fentanyl / Q000494:pharmacology; D006801:Humans; D006993:Hypnotics and Sedatives / Q000494:pharmacology; D008170:Lung Compliance / Q000502:physiology; D008176:Lung Volume Measurements; D008297:Male; D008875:Middle Aged; D011175:Positive-Pressure Respiration / Q000379:methods*; D015742:Propofol / Q000494:pharmacology; D011446:Prospective Studies; D011659:Pulmonary Gas Exchange / Q000502:physiology; D012121:Respiration, Artificial; D012128:Respiratory Distress Syndrome / Q000503:physiopathology / Q000628:therapy*; D015656:Respiratory Mechanics / Q000502:physiology; D014797:Vital Capacity
chemical_list: D018686:Anesthetics, Intravenous; D006993:Hypnotics and Sedatives; D005283:Fentanyl; D015742:Propofol