Intensive Care Medicine

, Volume 39, Issue 3, pp 463–471

Evaluation of fully automated ventilation: a randomized controlled study in post-cardiac surgery patients

  • François Lellouche
  • Pierre-Alexandre Bouchard
  • Serge Simard
  • Erwan L’Her
  • Marc Wysocki

DOI: 10.1007/s00134-012-2799-2

Cite this article as:
Lellouche, F., Bouchard, PA., Simard, S. et al. Intensive Care Med (2013) 39: 463. doi:10.1007/s00134-012-2799-2



Discrepancies between the demand and availability of clinicians to care for mechanically ventilated patients can be anticipated due to an aging population and to increasing severity of illness. The use of closed-loop ventilation provides a potential solution. The aim of the study was to evaluate the safety of a fully automated ventilator.


We conducted a randomized controlled trial comparing automated ventilation (AV) and protocolized ventilation (PV) in 60 ICU patients after cardiac surgery. In the PV group, tidal volume, respiratory rate, FiO2 and positive end-expiratory pressure (PEEP) were set according to the local hospital protocol based on currently available guidelines. In the AV group, only sex, patient height and a maximum PEEP level of 10 cmH2O were set. The primary endpoint was the duration of ventilation within a “not acceptable” range of tidal volume. Zones of optimal, acceptable and not acceptable ventilation were based on several respiratory parameters and defined a priori.


The patients were assigned equally to each group, 30 to PV and 30 to AV. The percentage of time within the predefined zones of optimal, acceptable and not acceptable ventilation were 12 %, 81 %, and 7 % respectively with PV, and 89.5 %, 10 % and 0.5 % with AV (P < 0.001). There were 148 interventions required during PV compared to only 5 interventions with AV (P < 0.001).


Fully AV was safe in hemodynamically stable patients immediately following cardiac surgery. In addition to a reduction in the number of interventions, the AV system maintained patients within a predefined target range of optimal ventilation.


Positive-pressure respiration Randomized trial Closed-loop Thoracic surgery Cardiac surgery Mechanical ventilation 

Supplementary material

134_2012_2799_MOESM1_ESM.docx (136 kb)
Supplementary material 1 (DOCX 135 kb)

Copyright information

© Springer-Verlag Berlin Heidelberg and ESICM 2013

Authors and Affiliations

  • François Lellouche
    • 1
  • Pierre-Alexandre Bouchard
    • 1
  • Serge Simard
    • 1
  • Erwan L’Her
    • 2
    • 3
  • Marc Wysocki
    • 4
  1. 1.Centre de recherche de l’Institut Universitaire de Cardiologie et de Pneumologie de QuébecUniversité LavalQuebec CityCanada
  2. 2.Hôtel Dieu de LévisQuebec CityCanada
  3. 3.Centre Hospitalier Universitaire La Cavale BlancheBrestFrance
  4. 4.GE Healthcare, Life Care Solution EuropeBucFrance