title: Initial synchronized intermittent mandatory ventilation versus assist/control ventilation in treatment of moderate acute respiratory distress syndrome: a prospective randomized controlled trial.
abstract: BACKGROUND
  Assist/control (A/C) ventilation may induce delirium in patients with acute respiratory distress syndrome (ARDS). We conducted a trial to determine whether initial synchronized intermittent mandatory ventilation with pressure support (SIMV + PS) could improve clinical outcomes in these patients.
  
  
  METHODS
  Intubated patients with moderate ARDS were enrolled and we compared SIMV + PS with A/C. Identical sedation, analgesia and ventilation strategies were performed. The co-primary outcomes were early (≤72 h) partial pressure of arterial oxygen to fraction of inspired oxygen (PaO2/FiO2) and incidence of delirium. The secondary outcomes were all-cause in-hospital mortality, dosages of analgesics and sedatives, incidence of patient-ventilator asynchrony, and duration of mechanical ventilation and hospital stay.
  
  
  RESULTS
  We screened 2,684 patients and 40 patients were enrolled in our study. In SIMV + PS, early (≤72 h) PaO2/FiO2 was greater improved than that at baseline and that in A/C (P<0.05) with lower positive end-expiratory pressure (PEEP) (8.7±3.0 vs. 10.3±3.2, P<0.001) and FiO2 (58%±18% vs. 67%±19%, P<0.001). We found more SIMV + PS success (defined as SIMV + PS successfully applied without switching to A/C) (100.0% vs. 16.7%, P<0.001), less male (46.3% vs. 85.7%, P=0.015) and pulmonary etiology of ARDS (53.8% vs. 92.9%, P=0.015), and lower PEEP (9.1±3.1 vs. 10.3±3.3, P=0.004) and FiO2 (58%±19% vs. 71%±19%, P<0.001) in survival patients. However, there were no significant differences in incidence of delirium and mortality, dosages of analgesics and sedatives, incidence of patient-ventilator asynchrony, duration of mechanical ventilation and hospital stay (P>0.05).
  
  
  CONCLUSIONS
  In patients with moderate ARDS, SIMV + PS can safely and effectively improve oxygenation, but does not decrease mortality, incidence of delirium and patient-ventilator asynchrony, dosages of analgesics and sedatives, and duration of mechanical ventilation and hospital stay.
authors.affiliation: 1 Department of Respiratory Medicine, 2 Department of Critical Care Medicine, West China School of Medicine and West China Hospital, Sichuan University, Chengdu 610041, China.
authors.forename: Jian
authors.initials: J
authors.lastname: Luo
authors.affiliation: 1 Department of Respiratory Medicine, 2 Department of Critical Care Medicine, West China School of Medicine and West China Hospital, Sichuan University, Chengdu 610041, China.
authors.forename: Mao-Yun
authors.initials: MY
authors.lastname: Wang
authors.affiliation: 1 Department of Respiratory Medicine, 2 Department of Critical Care Medicine, West China School of Medicine and West China Hospital, Sichuan University, Chengdu 610041, China.
authors.forename: Bin-Miao
authors.initials: BM
authors.lastname: Liang
authors.affiliation: 1 Department of Respiratory Medicine, 2 Department of Critical Care Medicine, West China School of Medicine and West China Hospital, Sichuan University, Chengdu 610041, China.
authors.forename: He
authors.initials: H
authors.lastname: Yu
authors.affiliation: 1 Department of Respiratory Medicine, 2 Department of Critical Care Medicine, West China School of Medicine and West China Hospital, Sichuan University, Chengdu 610041, China.
authors.forename: Fa-Ming
authors.initials: FM
authors.lastname: Jiang
authors.affiliation: 1 Department of Respiratory Medicine, 2 Department of Critical Care Medicine, West China School of Medicine and West China Hospital, Sichuan University, Chengdu 610041, China.
authors.forename: Ting
authors.initials: T
authors.lastname: Wang
authors.affiliation: 1 Department of Respiratory Medicine, 2 Department of Critical Care Medicine, West China School of Medicine and West China Hospital, Sichuan University, Chengdu 610041, China.
authors.forename: Chao-Li
authors.initials: CL
authors.lastname: Shi
authors.affiliation: 1 Department of Respiratory Medicine, 2 Department of Critical Care Medicine, West China School of Medicine and West China Hospital, Sichuan University, Chengdu 610041, China.
authors.forename: Pei-Jun
authors.initials: PJ
authors.lastname: Li
authors.affiliation: 1 Department of Respiratory Medicine, 2 Department of Critical Care Medicine, West China School of Medicine and West China Hospital, Sichuan University, Chengdu 610041, China.
authors.forename: Dan
authors.initials: D
authors.lastname: Liu
authors.affiliation: 1 Department of Respiratory Medicine, 2 Department of Critical Care Medicine, West China School of Medicine and West China Hospital, Sichuan University, Chengdu 610041, China.
authors.forename: Xiao-Ling
authors.initials: XL
authors.lastname: Wu
authors.affiliation: 1 Department of Respiratory Medicine, 2 Department of Critical Care Medicine, West China School of Medicine and West China Hospital, Sichuan University, Chengdu 610041, China.
authors.forename: Zong-An
authors.initials: ZA
authors.lastname: Liang
keywords: Respiratory distress syndrome; adult; artificial; delirium; mortality; respiration