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



After 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 CO2levels and in pH that may affect the results.



Six 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).



This 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.



ClinicalTrials.gov Identifier: NCT01490710 . Date of registration: December 7, 2011.
Pediatric Intensive Care Unit, Hôpital Femme-Enfant-Adolescent, the University Hospital Center of Nantes (CHU), 38 bd Jean-Monnet, 44093, Nantes, France. jeanmichel.liet@chu-nantes.fr.
Jean-Michel
0000-0002-4104-673X
JM
Liet
Pediatric Intensive Care Unit, Hôpital Femme-Enfant-Adolescent, the University Hospital Center of Nantes (CHU), 38 bd Jean-Monnet, 44093, Nantes, France.
François
F
Barrière
Pediatric Intensive Care Unit, Hôpital Femme-Enfant-Adolescent, the University Hospital Center of Nantes (CHU), 38 bd Jean-Monnet, 44093, Nantes, France.
Bénédicte
B
Gaillard-Le Roux
Pediatric Intensive Care Unit, Hôpital Femme-Enfant-Adolescent, the University Hospital Center of Nantes (CHU), 38 bd Jean-Monnet, 44093, Nantes, France.
Pierre
P
Bourgoin
Pediatric Intensive Care Unit, Hôpital Femme-Enfant-Adolescent, the University Hospital Center of Nantes (CHU), 38 bd Jean-Monnet, 44093, Nantes, France.|CIC-INSERM 1413, University of Nantes, Nantes, France.
Arnaud
A
Legrand
Pediatric Intensive Care Unit, Hôpital Femme-Enfant-Adolescent, the University Hospital Center of Nantes (CHU), 38 bd Jean-Monnet, 44093, Nantes, France.
Nicolas
N
Joram
D006348:Cardiac Surgical Procedures; D018592:Cross-Over Studies; D005260:Female; D006439:Hemodynamics; D006801:Humans; D007223:Infant; D059725:Interactive Ventilatory Support; D008168:Lung / Q000502:physiology*; D008297:Male; D017063:Outcome Assessment, Health Care; D010865:Pilot Projects; D011182:Postoperative Care / Q000379:methods*; D011446:Prospective Studies; D012121:Respiration, Artificial / Q000379:methods; D012129:Respiratory Function Tests
Cardiac index; Cardiac surgery; Children; Doppler ultrasonography; Electrical activity of diaphragm; Infants; Intensive care; Interactive ventilatory support; Mechanical ventilation; Neurally adjusted ventilatory assist