title: Positive end-expiratory pressure affects the value of intra-abdominal pressure in acute lung injury/acute respiratory distress syndrome patients: a pilot study.
abstract: BACKGROUND
  To examine the effects of positive end-expiratory pressure (PEEP) on intra-abdominal pressure (IAP) in patients with acute lung injury (ALI).
  
  
  METHODS
  Thirty sedated and mechanically ventilated patients with ALI or acute respiratory distress syndrome (ARDS) admitted to a sixteen-bed surgical medical ICU were included. All patients were studied with sequentially increasing PEEP (0, 6 and 12 cmH2O) during a PEEP-trial.
  
  
  RESULTS
  Age was 55 ± 17 years, weight was 70 ± 17 kg, SAPS II was 44 ± 14 and PaO2/FIO2 was 192 ± 53 mmHg. The IAP was 12 ± 5 mmHg at PEEP 0 (zero end-expiratory pressure, ZEEP), 13 ± 5 mmHg at PEEP 6 and 15 ± 6 mmHg at PEEP 12 (P < 0.05 vs ZEEP). In the patients with intra-abdominal hypertension defined as IAP ≥ 12 mmHg (n = 15), IAP significantly increased from 15 ± 3 mmHg at ZEEP to 20 ± 3 mmHg at PEEP 12 (P < 0.01). Whereas in the patients with IAP < 12 mmHg (n = 15), IAP did not significantly change from ZEEP to PEEP 12 (8 ± 2 vs 10 ± 3 mmHg). In the 13 patients in whom cardiac output was measured, increase in PEEP from 0 to 12 cmH2O did not significantly change cardiac output, nor in the 8 out of 15 patients of the high-IAP group. The observed effects were similar in both ALI (n = 17) and ARDS (n = 13) patients.
  
  
  CONCLUSIONS
  PEEP is a contributing factor that impacts IAP values. It seems necessary to take into account the level of PEEP whilst interpreting IAP values in patients under mechanical ventilation.
authors.affiliation: Intensive Care and Transplantation Unit, Department of Anaesthesiology and Critical Care, University Saint Eloi Hospital, 80 avenue Augustin Fliche, University of Montpellier I, F-34295 Montpellier Cedex 5, France. d-verzilli@chu-montpellier.fr
authors.forename: Daniel
authors.initials: D
authors.lastname: Verzilli
authors.forename: Jean-Michel
authors.initials: JM
authors.lastname: Constantin
authors.forename: Mustapha
authors.initials: M
authors.lastname: Sebbane
authors.forename: Gérald
authors.initials: G
authors.lastname: Chanques
authors.forename: Boris
authors.initials: B
authors.lastname: Jung
authors.forename: Pierre-François
authors.initials: PF
authors.lastname: Perrigault
authors.forename: Manu
authors.initials: M
authors.lastname: Malbrain
authors.forename: Samir
authors.initials: S
authors.lastname: Jaber
mesh_terms: D000005:Abdomen / Q000503:physiopathology; D055371:Acute Lung Injury / Q000503:physiopathology / Q000628:therapy*; D002302:Cardiac Output / Q000502:physiology; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010865:Pilot Projects; D011175:Positive-Pressure Respiration / Q000009:adverse effects / Q000379:methods; D011312:Pressure; D012128:Respiratory Distress Syndrome / Q000503:physiopathology / Q000628:therapy*