Wednesday, August 11, 2010

Autoregulation of ventilation with neurally adjusted ventilatory assist on extracorporeal lung support

Abstract
Purpose  
Extracorporeal membrane oxygenation (ECMO) can support oxygenation and carbon dioxide elimination in severe lung failure.
Usually it is accompanied by controlled mechanical ventilation. Neurally adjusted ventilatory assist (NAVA) is a new mode
of ventilation triggered by the diaphragmatic electrical activity and controlled by the patient's respiratory centre, which
may allow a close interaction between ventilation and extracorporeal perfusion. This pilot study intended to measure the physiologic
ventilatory response in patients with severe lung failure treated with ECMO and NAVA. We hypothesized that the combination
of both methods could automatically provide a protective ventilation with optimized blood gases.

Methods  
We report a case series of six patients treated with ECMO for severe lung failure. In the recovery phase of the disease, patients
were ventilated with NAVA and ventilatory response and gas exchange parameters were measured under different sweep gas flows
and temporarily inactivated ECMO.

Results  
Tidal volumes on ECMO ranged between 2 and 5 ml/kg predicted body weight and increased up to 8 ml/kg with inactivated ECMO.
Peak inspiratory pressure reached 19–29 cmH2O with active, and 21–45 cmH2O with inactivated ECMO. Ventilatory response to decreased sweep gas flow was rapid, and patients immediately regulated PaCO2 tightly towards a physiological pH value. Increase in minute ventilation was a result of increased breathing frequency and
tidal volumes, and protective ventilation was only abandoned if pH control was not achieved.

Conclusions  
With NAVA ventilatory response to decreased ECMO sweep gas flow was rapid, and patients immediately regulated PaCO2 tightly towards a physiological pH value. Therefore, combination of NAVA and ECMO may permit a closed-loop ventilation with
automated protective ventilation.

  • Content Type Journal Article
  • DOI 10.1007/s00134-010-1982-6
  • Authors
    • Christian Karagiannidis, Department of Internal Medicine II, University Hospital of Regensburg, Franz-Josef-Strauss-Allee 11, 93053 Regensburg, Germany
    • Matthias Lubnow, Department of Internal Medicine II, University Hospital of Regensburg, Franz-Josef-Strauss-Allee 11, 93053 Regensburg, Germany
    • Alois Philipp, Department of Cardiothoracic Surgery, University Hospital of Regensburg, Regensburg, Germany
    • Guenter A. J. Riegger, Department of Internal Medicine II, University Hospital of Regensburg, Franz-Josef-Strauss-Allee 11, 93053 Regensburg, Germany
    • Christof Schmid, Department of Cardiothoracic Surgery, University Hospital of Regensburg, Regensburg, Germany
    • Michael Pfeifer, Department of Internal Medicine II, University Hospital of Regensburg, Franz-Josef-Strauss-Allee 11, 93053 Regensburg, Germany
    • Thomas Mueller, Department of Internal Medicine II, University Hospital of Regensburg, Franz-Josef-Strauss-Allee 11, 93053 Regensburg, Germany
    • Journal Intensive Care Medicine
    • Online ISSN 1432-1238
    • Print ISSN 0342-4642

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