Neurally Adjusted Ventilatory Assist in Acute Respiratory Failure—A Narrative Review

Abstract

Maintaining spontaneous breathing has both potentially beneficial and deleterious consequences in patients with acute respiratory failure, depending on the balance that can be obtained between the protecting and damaging effects on the lungs and the diaphragm. Neurally adjusted ventilatory assist (NAVA) is an assist mode, which supplies the respiratory system with a pressure proportional to the integral of the electrical activity of the diaphragm. This proportional mode of ventilation has the theoretical potential to deliver lung- and respiratory-muscle-protective ventilation by preserving the physiologic defense mechanisms against both lung overdistention and ventilator overassistance, as well as reducing the incidence of diaphragm disuse atrophy while maintaining patient–ventilator synchrony. This narrative review presents an overview of NAVA technology, its basic principles, the different methods to set the assist level and the findings of experimental and clinical studies which focused on lung and diaphragm protection, machine–patient interaction and preservation of breathing pattern variability. A summary of the findings of the available clinical trials which investigate the use of NAVA in acute respiratory failure will also be presented and discussed.

Spinal cord perfusion pressure correlates with breathing function in patients with acute, cervical traumatic spinal cord injuries: an observational study

“…Diaphragmatic function was further assessed using the EDI nasogastric tube, initially designed for NAVA ventilation [ 12 , 13 ]. During quiet breathing, normal EDI-peak is 5–10 μV, and normal EDI-min is up to 1 μV.…”

“…We used ultrasound scanning (USS) to monitor non-invasively changes in diaphragmatic and intercostal muscle thickness and diaphragmatic excursion during breathing. We also recorded the electrical activity of the diaphragm (EDI) with NAVA (neurally adjusted ventilatory assist) nasogastric tubes [ 12 , 13 ].…”

A High Respiratory Drive Is Associated with Weaning Failure in Patients with COVID-19-Associated Acute Respiratory Distress Syndrome: The Role of the Electrical Activity of the Diaphragm

“…The electrical activity of the diaphragm (EAdi) is the spatial and temporal sum of the electrical activities of all the motor units of the diaphragm [14]. EAdi is measured via transesophageal diaphragmatic electromyography by the EAdi tube, a peculiar nasogastric tube with the traditional lumen for enteral feeding and eight pairs of bipolar electrodes placed at the distal end [15,16]. EAdi is considered the best proxy for the activity of neural respiratory centers (i.e., the respiratory drive) currently available in clinical practice [17].…”