NAVA, or neurally adjusted ventilatory assist, is a mode of mechanical ventilation that uses electrical signals from your diaphragm to control when and how much breathing support a ventilator delivers. Unlike conventional ventilation modes where a machine follows preset pressure or volume targets, NAVA lets the patient’s own brain and nervous system drive each breath. The ventilator essentially becomes a real-time amplifier of the patient’s natural breathing effort.
How NAVA Works
Every breath you take starts as an electrical signal. Your brain sends impulses down the phrenic nerve to the diaphragm, the dome-shaped muscle beneath your lungs. When the diaphragm contracts, it creates negative pressure that pulls air in. NAVA captures this electrical activity, called the Edi signal (electrical activity of the diaphragm), and uses it to control the ventilator.
The Edi signal does two things simultaneously. First, it tells the ventilator exactly when the patient wants to start and stop each breath, so the machine’s timing matches the patient’s timing. Second, the strength of the signal determines how much pressure the ventilator delivers. A strong Edi signal means the patient is working harder to breathe, so the machine provides more support. A weaker signal means less effort is needed, so support drops proportionally. This creates a feedback loop where the patient genuinely controls both the timing and the intensity of every assisted breath.
The Edi Catheter
NAVA requires a specialized feeding tube with tiny electrodes built into it. This tube looks and functions much like a standard nasogastric tube (the kind passed through the nose into the stomach), but the embedded sensors pick up electrical activity from the diaphragm as the tube passes through the lower esophagus, which sits right behind the diaphragm.
Placing the catheter follows a straightforward process. A clinician measures from the bridge of the nose to the earlobe and then down to the bottom of the breastbone to estimate the correct insertion depth. The tube is lubricated, passed through the nose or mouth, and connected to the ventilator. Once in place, the ventilator screen displays electrical waveforms that confirm the electrodes are sitting at the right level. Clinicians look for specific patterns in the heart’s electrical trace picked up by the catheter: the signals should be strongest in the upper electrodes and fade in the lower ones, while diaphragm activity should appear primarily in the middle electrodes. The diaphragm needs to generate a minimum signal (at least 2 to 3 microvolts) for NAVA mode to engage.
Better Synchrony With Breathing
One of the biggest challenges in mechanical ventilation is getting the machine to match the patient’s breathing pattern. With conventional modes, the ventilator relies on detecting airflow or pressure changes at the airway to figure out when a patient is trying to breathe. This indirect approach introduces delays and mismatches. The machine might deliver a breath when the patient is trying to exhale, or fail to detect a breathing effort altogether. These mismatches are called asynchrony, and they’re surprisingly common.
Because NAVA reads the diaphragm’s electrical signal directly, it bypasses the delays inherent in detecting airflow changes. A meta-analysis of pediatric ICU studies found that NAVA reduced the asynchrony index by roughly 12 percentage points compared to pressure support ventilation, a commonly used conventional mode. That’s a meaningful improvement. Poor synchrony increases discomfort, can prolong time on the ventilator, and may contribute to diaphragm weakening over time.
Benefits for Premature Infants
NAVA has found a particularly important role in neonatal intensive care. Premature babies have small, irregular breathing patterns that make conventional ventilator synchronization extremely difficult. Their breathing efforts are often too weak or too fast for standard ventilator triggers to detect reliably.
Studies in preterm infants show that NAVA reduces peak pressures delivered to the lungs, lowers oxygen requirements, and decreases episodes of apnea (pauses in breathing) compared to traditional synchronized ventilation modes. When used non-invasively (delivered through nasal prongs rather than a breathing tube), NAVA may reduce the need for intubation, support earlier removal of breathing tubes, and lower the rate of failed extubation attempts compared to standard continuous positive airway pressure (CPAP). For premature infants who experience frequent clinically significant events like drops in heart rate or oxygen levels, non-invasive NAVA has been shown to reduce the number of these episodes. This matters because it can help babies avoid the escalation to more invasive forms of respiratory support.
When NAVA Cannot Be Used
NAVA depends entirely on the diaphragm generating a readable electrical signal, which means several conditions rule it out. Phrenic nerve injury, where the nerve controlling the diaphragm is damaged, eliminates the signal NAVA needs. Congenital myopathy and other conditions that severely weaken the diaphragm have the same effect. Patients receiving neuromuscular blocking drugs (which paralyze muscles, including the diaphragm) or those under deep sedation won’t produce a usable Edi signal either.
Anatomical issues also matter. Esophageal atresia (where the esophagus doesn’t connect properly) or severe diaphragmatic hernia can prevent proper catheter placement or signal detection. Patients with conditions that make inserting a nasogastric tube dangerous, such as esophageal trauma, recent surgery in the area, or bleeding disorders, cannot receive the Edi catheter. The catheter must also be removed before MRI scanning, since the electrodes are not MRI-compatible. Frequent episodes of central apnea, where the brain temporarily stops sending breathing signals altogether, also make NAVA impractical because the ventilator would have no signal to follow during those pauses.
How NAVA Differs From Conventional Modes
In pressure support ventilation, the most common comparator, a clinician sets a fixed level of pressure that the ventilator delivers each time it detects a breath. Every breath gets the same amount of help regardless of how much effort the patient puts in. NAVA, by contrast, scales its support breath by breath. If you take a shallow, easy breath, you get less assist. If you take a deep, effortful breath, you get more. This proportional response more closely mimics how healthy breathing muscles naturally work.
This proportionality also creates a built-in safety feature during weaning, the process of gradually reducing ventilator support. As a patient’s respiratory muscles recover and the diaphragm generates stronger contractions, the Edi signal changes in ways that naturally communicate the patient’s readiness for less support. Clinicians can monitor the Edi trend over hours or days to gauge recovery, making weaning decisions based on objective data about the patient’s neural respiratory drive rather than relying solely on blood gas tests or clinical impression.
Invasive and Non-Invasive Use
NAVA can be delivered through a standard endotracheal tube (a breathing tube placed into the windpipe) for patients who need invasive ventilation. It can also be delivered non-invasively through a face mask or nasal interface, a version sometimes called NIV-NAVA. In both cases, the Edi catheter is the same. The difference is simply how air reaches the patient’s lungs.
Non-invasive NAVA has become especially valuable in neonatal care and in patients transitioning off invasive ventilation. Because the ventilator can detect breathing effort even when there are air leaks around a mask or nasal prongs (since it reads the diaphragm signal, not airflow), it maintains synchronization in situations where conventional non-invasive modes often struggle. Large leaks are one of the main reasons conventional non-invasive ventilation loses its ability to synchronize with the patient, so this is a practical advantage in real-world use.