title: A randomized controlled trial of adaptive support ventilation mode to wean patients after fast-track cardiac valvular surgery.
abstract: BACKGROUND
  Adaptive support ventilation can speed weaning after coronary artery surgery compared with protocolized weaning using other modes. There are no data to support this mode of weaning after cardiac valvular surgery. Furthermore, control group weaning times have been long, suggesting that the results may reflect control group protocols that delay weaning rather than a real advantage of adaptive support ventilation.
  
  
  METHODS
  Randomized (computer-generated sequence and sealed opaque envelopes), parallel-arm, unblinded trial of adaptive support ventilation versus physician-directed weaning after adult fast-track cardiac valvular surgery. The primary outcome was duration of mechanical ventilation. Patients aged 18 to 80 yr without significant renal, liver, or lung disease or severe impairment of left ventricular function undergoing uncomplicated elective valve surgery were eligible. Care was standardized, except postoperative ventilation. In the adaptive support ventilation group, target minute ventilation and inspired oxygen concentration were adjusted according to blood gases. A spontaneous breathing trial was carried out when the total inspiratory pressure of 15 cm H2O or less with positive end-expiratory pressure of 5 cm H2O. In the control group, the duty physician made all ventilatory decisions.
  
  
  RESULTS
  Median duration of ventilation was statistically significantly shorter (P = 0.013) in the adaptive support ventilation group (205 [141 to 295] min, n = 30) than that in controls (342 [214 to 491] min, n = 31). Manual ventilator changes and alarms were less common in the adaptive support ventilation group, and arterial blood gas estimations were more common.
  
  
  CONCLUSIONS
  Adaptive support ventilation reduces ventilation time by more than 2 h in patients who have undergone fast-track cardiac valvular surgery while reducing the number of manual ventilator changes and alarms.
authors.affiliation: From the Department of Anaesthesia and Intensive Care, The Chinese University of Hong Kong, Hong Kong, China (F.Z., C.D.G., S.K.N., A.L.); and Division of Cardiothoracic Surgery, Department of Surgery, The Chinese University of Hong Kong, Hong Kong, China (M.J.U.).
authors.forename: Fang
authors.initials: F
authors.lastname: Zhu
authors.forename: Charles D
authors.initials: CD
authors.lastname: Gomersall
authors.forename: Siu Keung
authors.initials: SK
authors.lastname: Ng
authors.forename: Malcolm J
authors.initials: MJ
authors.lastname: Underwood
authors.forename: Anna
authors.initials: A
authors.lastname: Lee
mesh_terms: D000328:Adult; D006348:Cardiac Surgical Procedures / Q000379:methods; D005260:Female; D006349:Heart Valve Diseases / Q000503:physiopathology / Q000601:surgery*; D019918:Heart Valve Prosthesis Implantation / Q000009:adverse effects / Q000379:methods*; D006801:Humans; D008297:Male; D008875:Middle Aged; D011182:Postoperative Care / Q000379:methods*; D012121:Respiration, Artificial / Q000009:adverse effects / Q000379:methods*; D013997:Time Factors; D015300:Ventilator Weaning / Q000379:methods*