The Effect of Prone vs Supine Position on Edi Signal in Neonates Receiving NAVA Ventilation

Abstract

Background:

Neurally-adjusted ventilatory assist (NAVA) is commonly used in neonates requiring mechanical ventilation. In NAVA, the electrical activity of the diaphragm (Edi) is used to trigger ventilator-delivered breaths. The amplitude of the Edi signal reflects the magnitude of diaphragmatic activation. Peak Edi reflects the neural inspiratory effort, while minimum Edi reflects the spontaneous tonic activity of the diaphragm. The set NAVA level dictates the proportional assist provided for a given Edi. Prone and side-lying positions offer benefits over supine position, including reduced V/Q mismatch, improved oxygenation, and reduced atelectasis. However, there is limited data on the effect of positioning on Edi amplitude in neonates receiving NAVA. Therefore, we aimed to determine the relationship between position and Edi signal during NAVA ventilation.

Methods:

With IRB approval, a retrospective chart review was conducted on patients in the NICU who received invasive and noninvasive NAVA between January 1 and May 15, 2023, at two different level III NICUs. The authors of this study employed computer data validation to ensure the accuracy and reliability of the collected data. Edi values, including peaks and minimums, were documented in prone and supine positions with the NAVA level held constant. The difference in Edi amplitude between positions was evaluated using a paired, two-tailed t-test.

Results:

The charts of twelve patients were reviewed. Nine patients had adequate data for analysis. Three patients were excluded due to minimal position change and insufficient time on NAVA. Mean Edi peak (7.5 ± 2.7 µV) and Edi min (1.8 ± 0.7 µV) in the prone position were significantly lower than in the supine position (12.1 ± 5.0 and 2.9 ± 1.2 µV for Edi peak and Edi min, respectively) (P < 0.01 for all comparisons).

Conclusions:

In neonates receiving NAVA ventilation, neural respiratory effort and resting diaphragm tone, as measured by peak and minimum Edi values, are lower in the prone position as compared to supine. Therefore, future prospective studies including larger sample sizes and a comparison of diverse ventilator settings, would be beneficial for optimization of NAVA in neonates and to better understand the impact of those differences.