Remifentanil effects on respiratory drive and timing during pressure support ventilation and neurally adjusted ventilatory assist

Increasing doses of remifentanil did not modify EAdi, regardless the ventilatory mode. In comparison to baseline, remifentanil infusion >0.05μg/Kg−1/min−1 produced a significant reduction of Ti/Ttotneu and Ti/Ttotmec, by prolonging the expiratory time. Delaytrinsp and Delaytrexp were significantly shorter in NAVA, respect to PSV. AI was not influenced by the different doses of remifentanil, but it was significantly lower during NAVA, compared to PSV. In conclusion remifentanil did not affect the respiratory drive, but only respiratory timing, without differences between modes.