Physiological effects of invasive ventilation with neurally adjusted ventilatory assist (NAVA) in a crossover study

Abstract

BackgroundNeurally Adjusted Ventilatory Assist (NAVA) is a mode of assisted mechanical ventilation that delivers inspiratory pressure proportionally to the electrical activity of the diaphragm. To date, no pediatric study has focused on the effects of NAVA on hemodynamic parameters. This physiologic study with a randomized cross-over design compared hemodynamic parameters when NAVA or conventional ventilation (CV) was applied.MethodsAfter a baseline period, infants received NAVA and CV in a randomized order during two consecutive 30-min periods. During the last 10 min of each period, respiratory and hemodynamic parameters were collected. No changes in PEEP, FiO2, sedation or inotropic doses were allowed during these two periods. The challenge was to keep minute volumes constant, with no changes in blood CO2 levels and in pH that may affect the results.ResultsSix infants who had undergone cardiac surgery (mean age 7.8 ± 4.1 months) were studied after parental consent. Four of them had low central venous oxygen saturation (ScvO2 < 65 %). The ventilatory settings resulted in similar minute volumes (1.7 ± 0.4 vs. 1.6 ± 0.6 ml/kg, P = 0.67) and in similar tidal volumes respectively with NAVA and with CV. There were no statistically significant differences on blood pH levels between the two modes of ventilation (7.32 ± 0.02 vs. 7.32 ± 0.04, P = 0.34). Ventilation with NAVA delivered lower peak inspiratory pressures than with CV: -32.7 % (95 % CI: -48.2 to –17.1 %, P = 0.04). With regard to hemodynamics, systolic arterial pressures were higher using NAVA: +8.4 % (95 % CI: +3.3 to +13.6 %, P = 0.03). There were no statistically significant differences on cardiac index between the two modes of ventilation. However, all children with a low baseline ScvO2 (<65 %) tended to increase their cardiac index with NAVA compared to CV: 2.03 ± 0.30 vs. 1.91 ± 0.39 L/min.m2 (median ± interquartile, P = 0.07).ConclusionsThis pilot study raises the hypothesis that NAVA could have beneficial effects on hemodynamics in children when compared to a conventional ventilatory mode that delivered identical PEEP and similar minute volumes.Trial registrationClinicalTrials.gov Identifier: NCT01490710. Date of registration: December 7, 2011.

Utilization of Neurally Adjusted Ventilatory Assist (NAVA) Mode in Infants and Children Undergoing Congenital Heart Surgery: A Retrospective Review

“…One of the promising advantages of NAVA is the delivery of lower peak pressures compared to other modes of mechanical ventilation [4,6,8,10,17,18]. These previously reported studies have demonstrated that when changing from conventional ventilation to NAVA, the PIP decreases and there is a tendency towards decreased P aw [8,16,19].…”

Pressure support ventilation, sigh adjunct to pressure support ventilation, and neurally adjusted ventilatory assist in infants after cardiac surgery: A physiologic crossover randomized study

“…Neurally Adjusted Ventilatory Assist (NAVA) and SIGH adjunct to PSV are two new modes of assisted ventilation that have been described in the last years in different pediatric setting, including postcardiosurgical patients . NAVA is a ventilatory mode that uses the electrical activity of the diaphragm (Eadi) to trigger, regulate, and cycle off the inspiratory pressure assistance; it has been shown to improve patient‐ventilator synchrony, to lower peak inspiratory pressure (PIP) and to accelerate the weaning process in one pediatric publication and to improve oxygenation as compared with PSV in one adult study . Conversely, a periodic “artificial recruiting breath” (SIGH) adjunct to PSV has been shown by our group to improve gas exchange and respiratory mechanics in postoperative (including cardiosurgical) ventilated children, without producing relevant complications in the short‐term .…”

Pressure Support Ventilation (PSV) versus Neurally Adjusted Ventilatory Assist (NAVA) in difficult to wean pediatric ARDS patients: a physiologic crossover study

“…In the abovementioned study [39], as in other studies [14,40], NAVA determined a significant reduction of peak inspiratory airway pressure and mean airway pressure when compared to conventional ventilation modes. In our study, peak inspiratory airway pressure was similar in all tested conditions, as we set the NAVA level to achieve similar peak inspiratory pressures to those observed during PSV.…”