title: Mechanical ventilation guided by esophageal pressure in acute lung injury.
abstract: BACKGROUND
  Survival of patients with acute lung injury or the acute respiratory distress syndrome (ARDS) has been improved by ventilation with small tidal volumes and the use of positive end-expiratory pressure (PEEP); however, the optimal level of PEEP has been difficult to determine. In this pilot study, we estimated transpulmonary pressure with the use of esophageal balloon catheters. We reasoned that the use of pleural-pressure measurements, despite the technical limitations to the accuracy of such measurements, would enable us to find a PEEP value that could maintain oxygenation while preventing lung injury due to repeated alveolar collapse or overdistention.
  
  
  METHODS
  We randomly assigned patients with acute lung injury or ARDS to undergo mechanical ventilation with PEEP adjusted according to measurements of esophageal pressure (the esophageal-pressure-guided group) or according to the Acute Respiratory Distress Syndrome Network standard-of-care recommendations (the control group). The primary end point was improvement in oxygenation. The secondary end points included respiratory-system compliance and patient outcomes.
  
  
  RESULTS
  The study reached its stopping criterion and was terminated after 61 patients had been enrolled. The ratio of the partial pressure of arterial oxygen to the fraction of inspired oxygen at 72 hours was 88 mm Hg higher in the esophageal-pressure-guided group than in the control group (95% confidence interval, 78.1 to 98.3; P=0.002). This effect was persistent over the entire follow-up time (at 24, 48, and 72 hours; P=0.001 by repeated-measures analysis of variance). Respiratory-system compliance was also significantly better at 24, 48, and 72 hours in the esophageal-pressure-guided group (P=0.01 by repeated-measures analysis of variance).
  
  
  CONCLUSIONS
  As compared with the current standard of care, a ventilator strategy using esophageal pressures to estimate the transpulmonary pressure significantly improves oxygenation and compliance. Multicenter clinical trials are needed to determine whether this approach should be widely adopted. (ClinicalTrials.gov number, NCT00127491.)
authors.affiliation: Department of Anesthesia, Critical Care, and Pain Medicine, Beth Israel Deaconess Medical Center, Boston 02215, USA. dtalmor@bidmc.harvard.edu
authors.forename: Daniel
authors.initials: D
authors.lastname: Talmor
authors.forename: Todd
authors.initials: T
authors.lastname: Sarge
authors.forename: Atul
authors.initials: A
authors.lastname: Malhotra
authors.forename: Carl R
authors.initials: CR
authors.lastname: O'Donnell
authors.forename: Ray
authors.initials: R
authors.lastname: Ritz
authors.forename: Alan
authors.initials: A
authors.lastname: Lisbon
authors.forename: Victor
authors.initials: V
authors.lastname: Novack
authors.forename: Stephen H
authors.initials: SH
authors.lastname: Loring
mesh_terms: D055371:Acute Lung Injury / Q000097:blood / Q000401:mortality / Q000503:physiopathology / Q000628:therapy*; D004947:Esophagus / Q000502:physiology; D005260:Female; D006801:Humans; D007362:Intensive Care Units; D007902:Length of Stay; D008168:Lung / Q000502:physiology; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D010100:Oxygen / Q000097:blood; D010865:Pilot Projects; D011175:Positive-Pressure Respiration / Q000379:methods*; D011312:Pressure; D012128:Respiratory Distress Syndrome / Q000097:blood / Q000401:mortality / Q000503:physiopathology / Q000628:therapy*; D013990:Tidal Volume
chemical_list: D010100:Oxygen