title: Automatic adjustment of pressure support by a computer-driven knowledge-based system during noninvasive ventilation: a feasibility study.
abstract: OBJECTIVE
  To evaluate the feasibility of using a knowledge-based system designed to automatically titrate pressure support (PS) to maintain the patient in a "respiratory comfort zone" during noninvasive ventilation (NIV) in patients with acute respiratory failure.
  
  
  METHODS
  Prospective crossover interventional study in an intensive care unit of a university hospital.
  
  
  METHODS
  Twenty patients.
  
  
  METHODS
  After initial NIV setting and startup in conventional PS by the chest physiotherapist NIV was continued for 45 min with the automated PS activated.
  
  
  RESULTS
  During automated PS minute-volume was maintained constant while respiratory rate decreased significantly from its pre-NIV value (20+/-3 vs. 25+/-3 bpm). There was a trend towards a progressive lowering of dyspnea. In hypercapnic patients PaCO(2) decreased significantly from 61+/-9 to 51+/-2 mmHg, and pH increased significantly from 7.31+/-0.05 to 7.35+/-0.03. Automated PS was well tolerated. Two system malfunctions occurred prompting physiotherapist intervention.
  
  
  CONCLUSIONS
  The results of this feasibility study suggest that the system can be used during NIV in patients with acute respiratory failure. Further studies should now determine whether it can improve patient-ventilator interaction and reduce caregiver workload.
authors.affiliation: University Hospital, Intensive Care, 1211 Geneva 14, Switzerland.
authors.forename: Anne
authors.initials: A
authors.lastname: Battisti
authors.forename: Jean
authors.initials: J
authors.lastname: Roeseler
authors.forename: Didier
authors.initials: D
authors.lastname: Tassaux
authors.forename: Philippe
authors.initials: P
authors.lastname: Jolliet
mesh_terms: D000368:Aged; D000704:Analysis of Variance; D018592:Cross-Over Studies; D005240:Feasibility Studies; D005260:Female; D006801:Humans; D008297:Male; D011312:Pressure; D011446:Prospective Studies; D012121:Respiration, Artificial / Q000379:methods*; D012131:Respiratory Insufficiency / Q000503:physiopathology / Q000628:therapy*; D015656:Respiratory Mechanics; D013813:Therapy, Computer-Assisted