Evaluation of the Relationship Between Electrical Activity of the Diaphragm and Respiratory Mechanics During Neurally Adjusted Ventilatory Assist in Lung Transplant Patients and in Patients Affected by Acute Respiratory Failure.

Lung transplantation (LTx) is an important treatment option for select patients with end-stage pulmonary disease, while acute respiratory failure is a common disease among ICU patients. In the early period, following LTx or at the beginning of acute respiratory failure, a protective ventilatory strategy should be applied to reduce ventilator-induced lung injury (VILI). Neurally Adjusted Ventilatory Assist (NAVA) is an assisted ventilation mode in which neural inspiratory activity is monitored through the continuous recording of electrical activity of the diaphragm (EAdi) and then used to coordinate the respiratory support delivered by the ventilator.

NAVA, because of its intrinsic properties (proportionality between respiratory drive and level of assist, prevention of diaphragm atrophy), could allow the aforementioned ventilatory strategy, however it may require the integrity of the pulmonary vagal afferent feedback in order to avoid volutrauma. So, the aim of the study is the evaluation of the physiological relationship between EAdi and tidal volume, driving pressure and mechanical power, at different levels of ventilatory assist, in the absence of pulmonary vagal afferent feedback during early post-operative period after LTx and among critically ill patients affected by acute respiratory failure. Finally, additional parameters will be collected: Pmus, Pocc, transpulmonary pressure etc.