Neurally Adjusted Ventilatory Assist Mode of Mechanical Ventilation in Neonates with Hypoxic-Ischemic Encephalopathy

Abstract

Ventilator support is considered to be one of the key components of intensive care in term neonates with mod-erate to severe hypoxic-ischemic encephalopathy (HIE). Most authors recommend mechanical ventilation during the peri-od of therapeutical hypothermia and after rewarming. Traditionally, pressure control ventilation has been used for ventilator support in neonates, but its disadvantage could be significant fluctuations in the pCO2 level which affects cerebral perfusion. An alternative may be the new neurally adjusted ventilatory assist (NAVA) mode of ventilation. There is a number of studies on using NAVA mode in newborns, both term and preterm, but its impact on cerebral perfusion compared to conventional modes is unknown. The aim. To compare the impact of NAVA and conventional modes of mechanical ventilation on cerebral perfusion dur-ing the acute period of HIE in term neonates. Materials and methods. Data on 205 term infants with Sarnat stage II–III HIE were collected during ≤ 72 hours of life. All the neonates were distributed by simple open randomization in NAVA group (n = 18) and control group (n = 187), which was stratified on subgroups of pressure control (РС) mode (n = 152), synchronized intermittent mandatory ventilation/ pressure support ventilation (SIMV/PSV) (n = 16) and pressure regulated volume control (PRVC) (n = 19). Comparative analysis of the influence of NAVA and other modes on cerebral perfusion during the acute period of neonatal HIE has been performed. Results and discussion. Compared to conventional modes of ventilation – PC, SIMV/PSV and PRVC, – NAVA group demonstrated significantly better Doppler indices of cerebral blood flow RI (0.66 [0.58–0.72] vs. 0.70 [0.67–0.74], р = 0.021) and РІ (1.2 [1.0–1.40] vs. 1.3 [1.2–1.5], р = 0.032) on the 3rd day of treatment, at the end of therapeutic hypother-mia period and at the start of rewarming. Subsequent analysis of variance (ANOVA) confirmed the positive impact of NAVA mode on cerebral perfusion (p = 0.009), but didn’t found significant correlations between Doppler indices of cerebral blood flow and PC (р = 0.140), SIMV/PSV (р = 0.446) and PRVC (р = 0.601) ventilation modes. Conclusion. Compared to conventional modes of ventilation (PC, SIMV/PSV and PRVC), NAVA demonstrated better profile of influence on cerebral perfusion indices in term neonates during the acute period of HIE.

Keywords

• hypoxia
• ischemia
• encephalopathy
• mechanical ventilation
• resistance index
• nava