 Neurally adjusted ventilatory assist NAVA is a FDA approved mode of mechanical ventilation. This mode of ventilation is currently in routine use in adult, pediatric and neonatal intensive care units. The electrical activity of the diaphragm, the largest muscle used during respiration, is measured. The ventilator applies support in proportion to the measured electrical activity of the diaphragm Edi. This electrical activity is measured through a feeding tube that also has a multiple-array esophageal electrode in it. 