Neurally adjusted ventilatory assist.

PURPOSE OF REVIEW: Compared with the conventional forms of partial support, neurally adjusted ventilatory assist was repeatedly shown to improve patient-ventilator synchrony and reduce the risk of overassistance, while guaranteeing adequate inspiratory effort and gas exchange. A few animal studies also suggested the potential of neurally adjusted ventilatory assist in averting the risk of ventilator-induced lung injury. Recent work adds new information on the physiological effects of neurally adjusted ventilatory assist.

RECENT FINDINGS: Compared with pressure support, neurally adjusted ventilatory assist has been shown to improve patient-ventilator interaction and synchrony in patients with the most challenging respiratory system mechanics, such as very low compliance consequent to severe acute respiratory distress syndrome and high resistance and air trapping due to chronic airflow obstruction; enhance redistribution of the ventilation in the dependent lung regions; avert the risk of patient-ventilator asynchrony due to sedation; avoid central apneas; limit the risk of high (injurious) tidal volumes in patients with acute respiratory distress syndrome of varied severity; and improve patient-ventilator interaction and synchrony during noninvasive ventilation, irrespective of the interface utilized.

SUMMARY: Several studies nowadays prove the physiological benefits of neurally adjusted ventilatory assist, as opposed to the conventional modes of partial support. Whether these advantages translate into improvement of clinical outcomes remains to be determined.