title: Performance of noninvasive ventilation algorithms on ICU ventilators during pressure support: a clinical study.
abstract: OBJECTIVE
  To evaluate the impact of noninvasive ventilation (NIV) algorithms available on intensive care unit ventilators on the incidence of patient-ventilator asynchrony in patients receiving NIV for acute respiratory failure.
  
  
  METHODS
  Prospective multicenter randomized cross-over study.
  
  
  METHODS
  Intensive care units in three university hospitals.
  
  
  METHODS
  Patients consecutively admitted to the ICU and treated by NIV with an ICU ventilator were included. Airway pressure, flow and surface diaphragmatic electromyography were recorded continuously during two 30-min periods, with the NIV (NIV+) or without the NIV algorithm (NIV0). Asynchrony events, the asynchrony index (AI) and a specific asynchrony index influenced by leaks (AIleaks) were determined from tracing analysis.
  
  
  RESULTS
  Sixty-five patients were included. With and without the NIV algorithm, respectively, auto-triggering was present in 14 (22%) and 10 (15%) patients, ineffective breaths in 15 (23%) and 5 (8%) (p = 0.004), late cycling in 11 (17%) and 5 (8%) (p = 0.003), premature cycling in 22 (34%) and 21 (32%), and double triggering in 3 (5%) and 6 (9%). The mean number of asynchronies influenced by leaks was significantly reduced by the NIV algorithm (p < 0.05). A significant correlation was found between the magnitude of leaks and AIleaks when the NIV algorithm was not activated (p = 0.03). The global AI remained unchanged, mainly because on some ventilators with the NIV algorithm premature cycling occurs.
  
  
  CONCLUSIONS
  In acute respiratory failure, NIV algorithms provided by ICU ventilators can reduce the incidence of asynchronies because of leaks, thus confirming bench test results, but some of these algorithms can generate premature cycling.
authors.affiliation: Service des Soins Intensifs, Hôpitaux universitaires de Genève, Geneva, Switzerland. Laurence.vignaux@hcuge.ch
authors.forename: Laurence
authors.initials: L
authors.lastname: Vignaux
authors.forename: Didier
authors.initials: D
authors.lastname: Tassaux
authors.forename: Guillaume
authors.initials: G
authors.lastname: Carteaux
authors.forename: Jean
authors.initials: J
authors.lastname: Roeseler
authors.forename: Lise
authors.initials: L
authors.lastname: Piquilloud
authors.forename: Laurent
authors.initials: L
authors.lastname: Brochard
authors.forename: Philippe
authors.initials: P
authors.lastname: Jolliet
mesh_terms: D000208:Acute Disease; D000368:Aged; D000465:Algorithms; D018592:Cross-Over Studies; D005260:Female; D006801:Humans; D007362:Intensive Care Units; D008297:Male; D011175:Positive-Pressure Respiration / Q000009:adverse effects; D011446:Prospective Studies; D012131:Respiratory Insufficiency / Q000503:physiopathology* / Q000628:therapy*