Diaphragmatic electromyography analysis during two different mechanical ventilation techniques in patients with neuromuscular diseases

The aim of the present study is to analyse changes in the diaphragmatic electromyography integral, as a direct expression of the patients inspiratory effort and index of neural respiratory drive, and parameters associated with ventilatory function in patients with prolonged weaning under Pressure Support Ventilation (PSV) and Neurally Adjusted Ventilatoy Assist (NAVA). Five patients affected by neuromuscular diseases were recruited. Each patient underwent a sequence of decreasing inspiratory support levels under NAVA and PSV, randomly assigned, from a baseline to a final level. At baseline, the value of diaphragmatic electromyography integral was higher under NAVA compared to PSV and increased in both ventilation modes progressing to final level. Higher values of inspiratory time and neural inspiratory time were observed in PSV at final level compared to baseline level. Conversely, a significant decrease of neural inspiratory time from baseline level to final level was observed in NAVA. Tidal volume at final level was significantly lower than at baseline level in both ventilation modes. These preliminary results show that in prolonged weaning patients affected by neuromuscular disease NAVA ventilation is associated to a higher diaphragmatic electromyography activity compared to PSV with same level of ventilation and subjective comfort.