title: Comparison of 3 modes of automated weaning from mechanical ventilation: a bench study.
abstract: OBJECTIVE
  Automated weaning modes are available in some mechanical ventilators, but no studies compared them hitherto. We compared the performance of 3 automated modes under standard and challenging situations.
  
  
  METHODS
  We used a lung simulator to compare 3 automated modes, adaptive support ventilation (ASV), mandatory rate ventilation (MRV), and Smartcare, in 6 situations, weaning success, weaning failure, weaning success with extreme anxiety, weaning success with Cheyne-Stokes, weaning success with irregular breathing, and weaning failure with ineffective efforts.
  
  
  RESULTS
  The 3 modes correctly recognized the situations of weaning success and failure, even when anxiety or irregular breathing were present but incorrectly recognized weaning success with Cheyne-Stokes. MRV incorrectly recognized weaning failure with ineffective efforts. Time to pressure support (PS) stabilization was shorter for ASV (1-2 minutes for all situations) and MRV (1-7 minutes) than for Smartcare (8-78 minutes). ASV had higher rates of PS oscillations per 5 minutes (4-15), compared with Smartcare (0-1) and MRV (0-12), except when extreme anxiety was present.
  
  
  CONCLUSIONS
  Smartcare, ASV, and MRV were equally able to recognize weaning success and failure, despite the presence of anxiety or irregular breathing but performed incorrectly in the presence of Cheyne-Stokes. PS behavior over the time differs among modes, with ASV showing larger and more frequent PS oscillations over the time. Clinical studies are needed to confirm our results.
authors.affiliation: Respiratory ICU, Pulmonary Department, Heart Institute, Incor, University of São Paulo Medical School, São Paulo, Brazil.
authors.forename: José B
authors.initials: JB
authors.lastname: Morato
authors.forename: Mayara T A
authors.initials: MT
authors.lastname: Sakuma
authors.forename: Juliana C
authors.initials: JC
authors.lastname: Ferreira
authors.forename: Pedro
authors.initials: P
authors.lastname: Caruso
mesh_terms: D006801:Humans; D008954:Models, Biological; D011175:Positive-Pressure Respiration / Q000379:methods; D015300:Ventilator Weaning / Q000295:instrumentation*; D012122:Ventilators, Mechanical