title: Noninvasive pressure support versus proportional assist ventilation in acute respiratory failure.
abstract: BACKGROUND
  Although conventional pressure ventilation (PSV) decreases the rate of intubation in acute respiratory failure, patient-ventilator dyssynchrony is a frequent cause of failure. In proportional assist ventilation (PAV), pressure is applied by the ventilator in proportion to the patient-generated volume and flow; therefore, there is automatic synchrony between the patient's effort and the ventilatory cycle.
  
  
  OBJECTIVE
  The aim of this study was to compare the effects of PSV and PAV during noninvasive ventilation in the treatment of acute respiratory failure.
  
  
  METHODS
  Prospective randomised study.
  
  
  METHODS
  A multidisciplinary 24-bed intensive care unit of an acute-care teaching hospital in Alicante, Spain. PATIENTS. This study included 117 consecutive adult patients with acute respiratory failure randomised to noninvasive ventilation delivered by PSV ( n = 59) or PAV ( n = 58).
  
  
  RESULTS
  There were no statistically significant differences between patients assigned to each mode of ventilation with regard to baseline parameters and aetiological diagnoses of acute respiratory failure. With regard to outcome data, no significant differences were observed between PSV and PAV in the frequency of intubation (37% vs 34%), mortality rate (29% vs 28%), and mean length of stay. Subjective comfort (0-10 visual analogue scale) was rated higher and intolerance occurred less frequently (3.4% vs 15%, P = 0.03) in the PAV than in the PSV mode.
  
  
  CONCLUSIONS
  Although PAV seems more comfortable and intolerance occurred less frequently, no major differences exist in terms of physiological improvement or in terms of outcomes when comparing PSV and PAV.
authors.affiliation: Intensive Care Unit, Hospital General Universitario de Alicante, Maestro Alonso 109, 03010, Alicante, Spain. mfvivas@ono.com
authors.forename: Miguel
authors.initials: M
authors.lastname: Fernández-Vivas
authors.forename: Juan
authors.initials: J
authors.lastname: Caturla-Such
authors.forename: Javier
authors.initials: J
authors.lastname: González de la Rosa
authors.forename: José
authors.initials: J
authors.lastname: Acosta-Escribano
authors.forename: Bernabé
authors.initials: B
authors.lastname: Alvarez-Sánchez
authors.forename: José
authors.initials: J
authors.lastname: Cánovas-Robles
mesh_terms: D000208:Acute Disease; D000328:Adult; D000368:Aged; D006784:Hospitals, Teaching; D006801:Humans; D008875:Middle Aged; D011446:Prospective Studies; D012121:Respiration, Artificial / Q000379:methods*; D012131:Respiratory Insufficiency / Q000503:physiopathology / Q000628:therapy*; D013030:Spain; D016896:Treatment Outcome