Effects of external diaphragmatic pacing with neurally adjusted ventilatory assist on diaphragm function in AECOPD patients

Diaphragm dysfunction, a prevalent complication in mechanically ventilated patients, is strongly associated with prolonged weaning periods and increased mortality rates. Neurally adjusted ventilatory assist (NAVA), which synchronizes ventilator support with neural respiratory drive through diaphragmatic electromyography monitoring, has demonstrated efficacy in preserving diaphragm contractility. Complementary to this, the external diaphragmatic pacing (EDP) mitigates ventilation-induced diaphragmatic atrophy through targeted phrenic nerve stimulation. However, the synergistic potential of the NAVA + EDP combination therapy in acute exacerbations of chronic obstructive pulmonary disease (AECOPD) remains unexplored. This prospective randomized trial enrolled 60 mechanically ventilated patients with AECOPD, who were equally allocated into three groups (n = 20 per group): conventional pressure support ventilation (PSV), neurally adjusted ventilatory assist (NAVA), and NAVA combined with external diaphragm pacing (NAVA + EDP). The primary outcome was diaphragmatic function, assessed using two ultrasonographic parameters: diaphragmatic excursion (DE) and diaphragm thickness fraction (DTF). Secondary outcomes included the following: (a) respiratory mechanics parameters, including electrical activity of the diaphragm (EAdi), plateau pressure (Pplat), static lung compliance (Cst), and airway resistance (Raw); (b) gas exchange indices, such as partial pressure of arterial carbon dioxide (PaCO₂) and PaO₂/FiO₂ ratio; and (c) clinical outcomes, namely duration of mechanical ventilation (DMV) and intensive care unit length of stay (ILOS). Compared to the PSV group, the NAVA group exhibited significantly higher DE and DTF values at 72 h and 96 h (all P < 0.05). Furthermore, the NAVA + EDP group demonstrated increased DE levels at 48 h, 72 h, and 96 h, along with elevated DTF values at 72 h and 96 h (all P < 0.05). Additionally, the NAVA group showed significantly shorter durations of DMV and ILOS compared to the PSV group, while the NAVA + EDP group further reduced both DMV and ILOS durations relative to the NAVA group (all P < 0.05). NAVA + EDP treatment exhibited effectively in reducing DMV and improving clinical outcomes for mechanically ventilated patients with AECOPD.