title: Pulmonary acute respiratory distress syndrome: positive end-expiratory pressure titration needs stress index.
abstract: BACKGROUND
  The heterogeneity of lung injury in pulmonary acute respiratory distress syndrome (ARDS) may have contributed to the greater response of hyperinflated area with positive end-expiratory pressure (PEEP). PEEP titrated by stress index can reduce the risk of alveolar hyperinflation in patients with pulmonary ARDS. The authors sought to investigate the effects of PEEP titrated by stress index on lung recruitment and protection after recruitment maneuver (RM) in pulmonary ARDS patients.
  
  
  METHODS
  Thirty patients with pulmonary ARDS were enrolled. After RM, PEEP was randomly set according to stress index, oxygenation, static pulmonary compliance (Cst), or lower inflection point (LIP) + 2 cmH2O strategies. Recruitment volume, gas exchange, respiratory mechanics, and hemodynamic parameters were collected.
  
  
  RESULTS
  PEEP titrated by stress index (15.1 ± 1.8 cmH2O) was similar to the levels titrated by oxygenation (14.5 ± 2.9 cmH2O), higher than that titrated by Cst (11.3 ± 2.5 cmH2O) and LIP (12.9 ± 1.6 cmH2O) (P < 0.05). Compared with baseline, PaO2/FiO2 and recruitment volume were significantly improved after PEEP titration with the four strategies (P < 0.05). PaO2/FiO2 and recruitment volume were similar when using PEEP titrated by stress index and oxygenation but higher than that titrated by Cst and LIP. Compared with baseline, lung compliance increased significantly when PEEP determined by Cst, but there was no difference of Cst in these four strategies. There was no influence of PEEP titration with the four strategies on hemodynamic parameters.
  
  
  CONCLUSIONS
  PEEP titration by stress index might be more beneficial for pulmonary ARDS patients after RM.
authors.affiliation: Department of Critical Care Medicine, Nanjing Zhong-Da Hospital, Southeast University School of Medicine, Nanjing, People's Republic of China.
authors.forename: Yingzi
authors.initials: Y
authors.lastname: Huang
authors.forename: Yi
authors.initials: Y
authors.lastname: Yang
authors.forename: Qiuhua
authors.initials: Q
authors.lastname: Chen
authors.forename: Songqiao
authors.initials: S
authors.lastname: Liu
authors.forename: Ling
authors.initials: L
authors.lastname: Liu
authors.forename: Chun
authors.initials: C
authors.lastname: Pan
authors.forename: Congshan
authors.initials: C
authors.lastname: Yang
authors.forename: Haibo
authors.initials: H
authors.lastname: Qiu
mesh_terms: D000328:Adult; D000368:Aged; D005260:Female; D006439:Hemodynamics / Q000502:physiology; D006801:Humans; D008170:Lung Compliance / Q000502:physiology; D008176:Lung Volume Measurements; D008297:Male; D008875:Middle Aged; D011175:Positive-Pressure Respiration / Q000379:methods*; D011659:Pulmonary Gas Exchange / Q000502:physiology; D012128:Respiratory Distress Syndrome / Q000503:physiopathology* / Q000628:therapy*; D015656:Respiratory Mechanics / Q000502:physiology; D013312:Stress, Physiological / Q000502:physiology; D016896:Treatment Outcome; D055397:Ventilator-Induced Lung Injury / Q000503:physiopathology* / Q000517:prevention & control*
keywords: Acute respiratory distress syndrome; Lower inflection point; Mechanical ventilation; Positive end-expiratory pressure; Recruitment maneuver; Stress index