Neural Breathing Pattern and Patient-Ventilator Interaction During Neurally Adjusted Ventilatory Assist and Conventional Ventilation in Newborns.

OBJECTIVE

To compare neurally adjusted ventilatory assist and conventional ventilation on patient-ventilator interaction and neural breathing patterns, with a focus on central apnea in preterm infants.

DESIGN

Prospective, observational cross-over study of intubated and ventilated newborns. Data were collected while infants were successively ventilated with three different ventilator conditions (30 min each period): 1) synchronized intermittent mandatory ventilation (SIMV) combined with pressure support at the clinically prescribed, SIMV with baseline settings (SIMVBL), 2) neurally adjusted ventilatory assist, 3) same as SIMVBL, but with an adjustment of the inspiratory time of the mandatory breaths (SIMV with adjusted settings [SIMVADJ]) using feedback from the electrical activity of the diaphragm).

SETTING

Regional perinatal center neonatal ICU.

PATIENTS

Neonates admitted in the neonatal ICU requiring invasive mechanical ventilation.

MEASUREMENTS AND MAIN RESULTS

Twenty-three infants were studied, with median (range) gestational age at birth 27 weeks (24-41 wk), birth weight 780 g (490-3,610 g), and 7 days old (1-87 d old). Patient ventilator asynchrony, as quantified by the NeuroSync index, was lower during neurally adjusted ventilatory assist (18.3% ± 6.3%) compared with SIMVBL (46.5% ±11.7%; p < 0.05) and SIMVADJ (45.8% ± 9.4%; p < 0.05). There were no significant differences in neural breathing parameters, or vital signs, except for the end-expiratory electrical activity of the diaphragm, which was lower during neurally adjusted ventilatory assist. Central apnea, defined as a flat electrical activity of the diaphragm more than 5 seconds, was significantly reduced during neurally adjusted ventilatory assist compared with both SIMV periods. These results were comparable for term and preterm infants.

CONCLUSIONS

Patient-ventilator interaction appears to be improved with neurally adjusted ventilatory assist. Analysis of the neural breathing pattern revealed a reduction in central apnea during neurally adjusted ventilatory assist use.