title: Factors associated with adherence to low-tidal volume strategy for acute lung injury and acute respiratory distress syndrome and their impacts on outcomes: an observational study and propensity analysis.
abstract: BACKGROUND
  The purpose of this study was to investigate the factors affecting adherence to the low-tidal volume (LTV) strategy in acute lung injury (ALI) and acute respiratory distress syndrome (ARDS) and their impacts on outcomes.
  
  
  METHODS
  This prospective observational study included 111 patients with ALI/ARDS admitted to six intensive care units between March 2010 and February 2011. The patients were divided into the LTV group, which received a TV ≤7.5 mL/kg predicted body weight (PBW), and the non-LTV group, which received a TV >7.5 mL/kg PBW. We studied the association of selected clinical factors and adherence to the LTV strategy, and evaluated their impacts on 28-day mortality and 1-year mortality by the propensity-match process.
  
  
  RESULTS
  Adherence to the LTV strategy was only 44%, which was related to lung injury severity (odds ratio [OR]: 3.15, P=0.038), muscle relaxant use (OR: 3.28, P=0.031), and depth of sedation (OR: 0.65, P=0.008). Propensity score-based analysis showed that the LTV group had modestly better 28-day survival (P=0.081) and 1-year survival (P=0.067) than the non-LTV group. Moreover, muscle relaxant use was strongly associated with reducing the risk of death at both 28 days (hazard ratio [HR]: 0.122, 95% confidence interval [CI]: 0.027-0.542, P=0.006) and 1 year ([HR]: 0.111, 95% [CI]: 0.030-0.408, P=0.001).
  
  
  CONCLUSIONS
  Adherence to the LTV strategy was strongly associated with the lung injury score, muscle relaxant use, and depth of sedation. Propensity score-based analysis showed that the use of LTV ventilation and muscle relaxants reduced 28-day and 1-year mortality in ALI/ARDS patients.
authors.affiliation: Department of Internal Medicine, National Taiwan University Hospital Yun-Lin Branch, Douliou City, Yunlin County, Taiwan - jsjerng@ntu.edu.tw.
authors.forename: Y F
authors.initials: YF
authors.lastname: Chen
authors.forename: C K
authors.initials: CK
authors.lastname: Lim
authors.forename: S Y
authors.initials: SY
authors.lastname: Ruan
authors.forename: J S
authors.initials: JS
authors.lastname: Jerng
authors.forename: J W
authors.initials: JW
authors.lastname: Lin
authors.forename: P H
authors.initials: PH
authors.lastname: Kuo
authors.forename: H D
authors.initials: HD
authors.lastname: Wu
authors.forename: C J
authors.initials: CJ
authors.lastname: Yu
mesh_terms: D055371:Acute Lung Injury / Q000401:mortality / Q000628:therapy*; D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009125:Muscle Relaxants, Central / Q000627:therapeutic use; D057216:Propensity Score; D011446:Prospective Studies; D012121:Respiration, Artificial / Q000379:methods* / Q000592:standards; D012128:Respiratory Distress Syndrome / Q000401:mortality / Q000628:therapy*; D013990:Tidal Volume; D016896:Treatment Outcome; D055815:Young Adult
chemical_list: D009125:Muscle Relaxants, Central