title: Non-invasive negative and positive pressure ventilation in the treatment of acute on chronic respiratory failure.
abstract: OBJECTIVE
  To investigate in clinical practice the role of non-invasive mechanical ventilation in the treatment of acute respiratory failure on chronic respiratory disorders.
  
  
  METHODS
  An 18 months prospective cohort study.
  
  
  METHODS
  A specialised respiratory intensive care unit in a university-affiliated hospital.
  
  
  METHODS
  A total of 258 consecutive patients with acute respiratory failure on chronic respiratory disorders.
  
  
  METHODS
  Criteria for starting non-invasive mechanical ventilation and for endotracheal intubation were predefined. Non-invasive mechanical ventilation was provided by positive pressure (NPPV) ventilators or iron lung (NPV).
  
  
  RESULTS
  The main characteristics of patients (70% with chronic obstructive pulmonary disease) on admission were (mean, SD or median, 25th-75th centiles): pH 7.29 (0.07), PaCO(2) 83 mm Hg (19), PaO(2)/FiO(2) 198 (77), APACHE II score 19 (15-24). Among the 258 patients, 200 (77%) were treated exclusively with non-invasive mechanical ventilation (40% with NPV, 23% with NPPV, and 14% with the sequential use of both), and 35 (14%) with invasive mechanical ventilation. In patients in whom NPV or NPPV failed, the sequential use of the alternative non-invasive ventilatory technique allowed a significant reduction in the failure of non-invasive mechanical ventilation (from 23.4 to 8.8%, p=0.002, and from 25.3 to 5%, p=0.0001, respectively). In patients as a whole, the hospital mortality (21%) was lower than that estimated by APACHE II score (28%).
  
  
  CONCLUSIONS
  Using NPV and NPPV it was possible in clinical practice to avoid endotracheal intubation in the large majority of unselected patients with acute respiratory failure on chronic respiratory disorders needing ventilatory support. The sequential use of both modalities may increase further the effectiveness of non-invasive mechanical ventilation.
authors.affiliation: Respiratory Intensive Care Unit, Careggi Hospital CTO, Largo Palagi 1, 50134 Florence, Italy. massimogorini@libero.it
authors.forename: Massimo
authors.initials: M
authors.lastname: Gorini
authors.forename: Roberta
authors.initials: R
authors.lastname: Ginanni
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Villella
authors.forename: Donatella
authors.initials: D
authors.lastname: Tozzi
authors.forename: Annike
authors.initials: A
authors.lastname: Augustynen
authors.forename: Antonio
authors.initials: A
authors.lastname: Corrado
mesh_terms: D018806:APACHE; D000368:Aged; D001784:Blood Gas Analysis; D017052:Hospital Mortality; D006801:Humans; D007362:Intensive Care Units; D007902:Length of Stay; D011175:Positive-Pressure Respiration / Q000379:methods*; D011446:Prospective Studies; D029424:Pulmonary Disease, Chronic Obstructive / Q000145:classification / Q000628:therapy*; D012128:Respiratory Distress Syndrome / Q000145:classification / Q000628:therapy*; D015919:Ventilators, Negative-Pressure