Autoregulation of ventilation with neurally adjusted ventilatory assist on extracorporeal lung support.
OBJECTIVE
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 cmH(2)O with active, and 21-45 cmH(2)O with inactivated ECMO. Ventilatory response to decreased sweep gas flow was rapid, and patients immediately regulated PaCO(2) 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 PaCO(2) tightly towards a physiological pH value. Therefore, combination of NAVA and ECMO may permit a closed-loop ventilation with automated protective ventilation.
Karagiannidis
Christian
C
Department of Internal Medicine II, University Hospital of Regensburg, Franz-Josef-Strauss-Allee 11, 93053, Regensburg, Germany. karagiannidis@email.de
Lubnow
Matthias
M
Philipp
Alois
A
Riegger
Guenter A J
GA
Schmid
Christof
C
Pfeifer
Michael
M
Mueller
Thomas
T
D000328:Adult; D003964:Diaphragm / Q000502:physiology; D055724:Electrophysiological Phenomena; D015199:Extracorporeal Membrane Oxygenation; D005260:Female; D006801:Humans; D008297:Male; D010865:Pilot Projects; D011446:Prospective Studies; D012121:Respiration, Artificial / Q000379:methods*; D012131:Respiratory Insufficiency / Q000628:therapy*