title: Automatic control of pressure support for ventilator weaning in surgical intensive care patients.
abstract: BACKGROUND
  Despite its ability to reduce overall ventilation time, protocol-guided weaning from mechanical ventilation is not routinely used in daily clinical practice. Clinical implementation of weaning protocols could be facilitated by integration of knowledge-based, closed-loop controlled protocols into respirators.
  
  
  OBJECTIVE
  To determine whether automated weaning decreases overall ventilation time compared with weaning based on a standardized written protocol in an unselected surgical patient population.
  
  
  METHODS
  In this prospective controlled trial patients ventilated for longer than 9 hours were randomly allocated to receive either weaning with automatic control of pressure support ventilation (automated-weaning group) or weaning based on a standardized written protocol (control group) using the same ventilation mode. The primary end point of the study was overall ventilation time.
  
  
  RESULTS
  Overall ventilation time (median [25th and 75th percentile]) did not significantly differ between the automated-weaning (31 [19-101] h; n = 150) and control groups (39 [20-118] h; n = 150; P = 0.178). Patients who underwent cardiac surgery (n = 132) exhibited significantly shorter overall ventilation times in the automated-weaning (24 [18-57] h) than in the control group (35 [20-93] h; P = 0.035). The automated-weaning group exhibited shorter ventilation times until the first spontaneous breathing trial (1 [0-15] vs. 9 [1-51] h; P = 0.001) and a trend toward fewer tracheostomies (17 vs. 28; P = 0.075).
  
  
  CONCLUSIONS
  Overall ventilation times did not significantly differ between weaning using automatic control of pressure support ventilation and weaning based on a standardized written protocol. Patients after cardiac surgery may benefit from automated weaning. Implementation of additional control variables besides the level of pressure support may further improve automated-weaning systems. Clinical trial registered with www.clinicaltrials.gov (NCT 00445289).
authors.affiliation: Department of Anesthesiology and Intensive Care Medicine, University Medical Center Schleswig-Holstein, Campus Kiel, Kiel, Germany. schaedler@anaesthesie.uni-kiel.de
authors.forename: Dirk
authors.initials: D
authors.lastname: Schädler
authors.forename: Christoph
authors.initials: C
authors.lastname: Engel
authors.forename: Gunnar
authors.initials: G
authors.lastname: Elke
authors.forename: Sven
authors.initials: S
authors.lastname: Pulletz
authors.forename: Nils
authors.initials: N
authors.lastname: Haake
authors.forename: Inéz
authors.initials: I
authors.lastname: Frerichs
authors.forename: Günther
authors.initials: G
authors.lastname: Zick
authors.forename: Jens
authors.initials: J
authors.lastname: Scholz
authors.forename: Norbert
authors.initials: N
authors.lastname: Weiler
mesh_terms: D000368:Aged; D001331:Automation / Q000379:methods*; D006348:Cardiac Surgical Procedures; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007362:Intensive Care Units; D008297:Male; D008875:Middle Aged; D011312:Pressure; D011446:Prospective Studies; D012121:Respiration, Artificial; D015300:Ventilator Weaning / Q000379:methods*