Robin Pouyau

To determine the prevalence of main inspiratory asynchrony events during non-invasive intermittent positive-pressure ventilation (NIV) for severe bronchiolitis. Ventilator response time and asynchrony were compared in neurally adjusted ventilator assist (NAVA) and in pressure assist/control (PAC) modes. This prospective physiological study was performed in a university hospital's paediatric intensive care unit and included 11 children (aged 35.2 ± 23 days) with respiratory syncytial virus bronchiolitis with failure of nCPAP. Patients received NIV for 2 hr in PAC mode followed by 2 hr in NAVA mode. Electrical activity of the diaphragm and pressure curves were recorded for 10 min. Trigger delay, main asynchronies (auto-triggering, double triggering, or non-triggered breaths) were analyzed, and the asynchrony index was calculated for each period. The asynchrony index was lower during NAVA than during PAC (3 ± 3% vs. 38 ± 21%, P < 0.0001), and the trigger delay was shorter (43.9 ± 7.2 vs. 116.0 ± 38.9 ms, P < 0.0001). Ineffective efforts were significantly less frequent in NAVA mode (0.54 ± 1.5 vs. 21.8 ± 16.5 events/min, P = 0.01). Patient respiratory rates were similar, but the ventilator rate was higher in NAVA than in PAC mode (59.5 ± 17.9 vs. 49.8 ± 8.5/min, P = 0.03). The TcPCO2 baselines values (64 ± 12 mmHg vs. 62 ± 9 mmHg during NAVA, P = 0.30) were the same and their evolution over the 2 hr study period (-6 ± 10 mmHg vs. -12 ± 17 mmHg during NAVA, P = 0.36) did not differ. Patient-ventilator inspiratory asynchronies and trigger delay were dramatically lower in NAVA mode than in PAC mode during NIV in infants with severe bronchiolitis.

Acute bronchiolitis is the most common lower respiratory tract infection (LRTI) during the first year of life. Respiratory syncytial virus (RSV) infection is the most prevalent virus found in these children, accounting for 60–80 % of cases. The rate of hospitalization is less than 2 %. Up to 8 % of those hospitalized require ventilatory support [1, 2].